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  • 1.
    Andersson, Erik
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Govus, Andrew
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. La Trobe University, Melbourne, VIC, Australia.
    Shannon, Oliver Michael
    Newcastle University, Newcastle upon Tyne, United Kingdom.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Sex differences in performance and pacing strategies during sprint skiing2019In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, article id 295Article in journal (Refereed)
    Abstract [en]

    Purpose: This study aimed to compare performance and pacing strategies between elite male and female cross-country skiers during a sprint competition on snow using the skating technique.

    Methods: Twenty male and 14 female skiers completed an individual time-trial prolog (TT) and three head-to-head races (quarter, semi, and final) on the same 1,572-m course, which was divided into flat, uphill and downhill sections. Section-specific speeds, choice of sub-technique (i.e., gear), cycle characteristics, heart rate and post-race blood lactate concentration were monitored. Power output was estimated for the different sections during the TT, while metabolic demand was estimated for two uphill camera sections and the final 50-m flat camera section.

    Results: Average speed during the four races was ∼12.5% faster for males than females (P < 0.001), while speeds on the flat, uphill and downhill sections were ∼11, 18, and 9% faster for the males than females (all P< 0.001 for terrain, sex, and interaction). Differences in uphill TT speed between the sexes were associated with different sub-technique preferences, with males using a higher gear more frequently than females (P < 0.05). The estimated metabolic demand relative to maximal oxygen uptake (V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V˙V˙O2max) was similar for both sexes during the two uphill camera sections (∼129% of V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V˙V˙O2max) and for the final 50-m flat section (∼153% of V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V˙V˙O2max). Relative power output during the TT was 18% higher for males compared to females (P < 0.001) and was highly variable along the course for both sexes (coefficient of variation [CV] between sections 4–9 was 53%), while the same variation in heart rate was low (CV was ∼3%). The head-to-head races were ∼2.4% faster than the TT for both sexes and most race winners (61%) were positioned first already after 30 m of the race. No sex differences were observed during any of the races for heart rate or blood lactate concentration.

    Conclusion: The average sex difference in sprint skiing performance was ∼12.5%, with varying differences for terrain-specific speeds. Moreover, females skied relatively slower uphill (at a lower gear) and thereby elicited more variation in their speed profiles compared to the males.

  • 2.
    Andersson, Erik
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    A Comparison between Different Methods of Estimating Anaerobic Energy Production2018In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, no FEB, article id 82Article in journal (Refereed)
    Abstract [en]

    Purpose: The present study aimed to compare four methods of estimating anaerobic energy production during supramaximal exercise.

    Methods: Twenty-one junior cross-country skiers competing at a national and/or international level were tested on a treadmill during uphill (7°) diagonal-stride (DS) roller-skiing. After a 4-minute warm-up, a 4 × 4-min continuous submaximal protocol was performed followed by a 600-m time trial (TT). For the maximal accumulated O2 deficit (MAOD) method the V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2-speed regression relationship was used to estimate the V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2 demand during the TT, either including (4+Y, method 1) or excluding (4-Y, method 2) a fixed Y-intercept for baseline V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2. The gross efficiency (GE) method (method 3) involved calculating metabolic rate during the TT by dividing power output by submaximal GE, which was then converted to a V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2 demand. An alternative method based on submaximal energy cost (EC, method 4) was also used to estimate V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2 demand during the TT.

    Results: The GE/EC remained constant across the submaximal stages and the supramaximal TT was performed in 185 ± 24 s. The GE and EC methods produced identical V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2 demands and O2 deficits. The V." role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative; outline: 0px !important;">V.V.O2 demand was ~3% lower for the 4+Y method compared with the 4-Y and GE/EC methods, with corresponding O2 deficits of 56 ± 10, 62 ± 10, and 63 ± 10 mL·kg−1, respectively (P < 0.05 for 4+Y vs. 4-Y and GE/EC). The mean differences between the estimated O2 deficits were −6 ± 5 mL·kg−1 (4+Y vs. 4-Y, P < 0.05), −7 ± 1 mL·kg−1 (4+Y vs. GE/EC, P < 0.05) and −1 ± 5 mL·kg−1 (4-Y vs. GE/EC), with respective typical errors of 5.3, 1.9, and 6.0%. The mean difference between the O2 deficit estimated with GE/EC based on the average of four submaximal stages compared with the last stage was 1 ± 2 mL·kg−1, with a typical error of 3.2%.

    Conclusions: These findings demonstrate a disagreement in the O2 deficits estimated using current methods. In addition, the findings suggest that a valid estimate of the O2 deficit may be possible using data from only one submaximal stage in combination with the GE/EC method.

  • 3.
    Andersson, Erik
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    A Comparison Between Different Methods Of Estimating Anaerobic Energy Production During Cross-Country Roller-Skiing2016Conference paper (Refereed)
    Abstract [en]

    Introduction

    Two frequently used approaches for estimating anaerobic energy production during supramaximal exercise are the maximal accumulated oxygen (O2) deficit (MAOD) method and the gross efficiency (GE) method (Noordhof et al., 2011). Despite clear computational differences between the two methods, only one direct comparison has been performed (Noordhof et al., 2011). In cross-country roller-skiing, both the MAOD and the GE methods have been employed (Andersson et al., 2016). Therefore, this study aimed to compare the O2 deficits attained with these methods.

    Methods

    Eleven male and ten female cross-country skiers were tested on a treadmill employing uphill (7°) diagonal-stride roller-skiing. After collecting a 1-min baseline VO2, participants performed a 4 × 4-min continuous submaximal protocol (~ 60-90% of VO2max) followed by, a self-paced 600-m time-trial (TT). Speed and VO2 were measured continuously during the TT. For the MAOD method, the linear relationship between treadmill velocity and VO2 during the final 30 seconds of each 4 × 4-min submaximal stage was derived with the baseline VO2 as a Y-intercept included (4+Y) in or excluded (4-Y) from the model. The two regression equations were then used to estimate the VO2 demand during the TT. For the GE method, the metabolic rate during the TT was calculated by taking the average power output divided by the GE (an average of the four submaximal stages) and converted to a VO2 demand. 

    Results

    The VO2 demand was significantly higher for the GE (68.9 ± 8.5 mL/kg/min) and 4-Y (68.4 ± 8.7 mL/kg/min) procedures compared with the 4+Y (64.3 ± 7.6 mL/kg/min) procedure (P < 0.05). The corresponding O2 deficits for the GE, 4-Y and, 4+Y procedures were 63.7 ± 9.7, 62.3 ± 10.4 and, 50.2 ± 9.6 mL/kg, respectively (P < 0.05 for GE and 4-Y vs. 4+Y). The mean difference between the O2 deficits estimated from the 4-Y and GE procedure -1.4 ± 3.9 mL/kg, and between the 4+Y and GE procedures was -13.5 ± 2.5 mL/kg.  Corresponding typical errors for the two comparisons were 2.74% and 1.74% while the intra-class correlation coefficients together with linear equations were r = 0.93 (0.99x – 0.8) for [4-Y vs. GE] and r = 0.97 (0.95x - 10.5) for [4+Y vs. GE].

    Discussion

    The main finding of the current study was the high agreement between the 4-Y and GE procedures which is in contrast to previous findings of Noordhof et al. (2011). Moreover, the inclusion of a Y-intercept for baseline VO2 resulted in a 20% lower O2 deficit compared to the 4-Y and GE procedures.  

    References

    Andersson E, Björklund G, Holmberg HC, Ørtenblad N. (2016). Scand J Med Sci Sports. Noordhof DA, Vink AM, de Koning JJ. Foster C. (2011). Int J Sports Med, 32, 422-8

  • 4.
    Andersson, Erik P.
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Govus, Andrew
    Department of Rehabilitation, Nutrition and Sport, La Trobe University, Australia.
    Shannon, Oliver M.
    Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, United Kingdom.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Sex differences in performance and pacing strategies during a sprint time-trial in cross-country skiing2018Conference paper (Refereed)
    Abstract [en]

    INTRODUCTION: The aim of this study was to compare the pacing strategies, choice of sub-technique (i.e., gear) and overall performance between elite male and female cross-country (XC) skiers during a ski-skating sprint time-trial (TT) on snow.

    METHODS: Thirty-four elite XC skiers (20 males and 14 females: age, 23 ± 4 and 21 ± 3 yr; body mass, 76 ± 8 and 64 ± 5 kg; height, 183 ± 7 and 171 ± 5 cm; sprint FIS points, 86 ± 42 and 90 ± 54) performed a 1.6 km TT, which was 56% flat (or undulating), 21% uphill and 22% downhill. The sprint course was measured with a differential global navigation satellite system and divided into four flat, three uphill and two downhill sections. Race time was measured with the EMIT timing system (Emit AS, Oslo, Norway) and one 25-m uphill (4°) section was filmed continuously with a fixed camcorder (50 Hz). All skiers used a similar stone-grind and all skis were glide-waxed similarly. The air temperature was +1°C (fresh snow at ±0°C), relative humidity was 90% and the friction coefficient between ski and snow was estimated to 0.045 (i.e., very slow).

    RESULTS: Average speed during the TT was 25 ± 1 and 22 ± 1 km/h (TT time: 227 ± 11 and 254 ± 10 s) for males and females, respectively (P < 0.001, Cohen’s d effect size [ES] = 2.6). Average relative power output (PO) was estimated to 3.9 ± 0.3 and 3.3 ± 0.2 W/kg for males and females, respectively (P < 0.001, ES = 2.5). Average heart rate was 95 ± 2% and 96 ± 1% of maximum for males and females (P = 0.51), with a 2-min post-race blood lactate concentration of 10 ± 2 mmol/L for both sexes (P = 0.64). Within-athlete coefficient of variation in speed between sections was 20 ± 2% for males and 24 ± 1% for females (P < 0.001, ES = 2.6). Speeds on the flat, uphill and downhill sections were 26 ± 1, 19 ± 1 and 32 ± 1 km/h for males and 23 ± 1, 16 ± 1 and 30 ± 1 km/h for females (main effects for terrain, sex and interaction, all P < 0.01) corresponding to 9%, 16% and 8% slower speeds on flat, uphill and downhill terrain for females. Speeds relative to the average TT speed were 103 ± 1%, 77 ± 2% and 129 ± 4% for males and 105 ± 1%, 72 ± 2% and 133 ± 2% for females (main effects for terrain, sex and interaction, all P < 0.001). Relative PO on the flat, uphill and downhill sections were estimated to 4.0 ± 0.3, 4.9 ± 0.4 and 1.9 ± 0.2 W/kg for males and 3.5 ± 0.2, 4.0 ± 0.3 and 1.5 ± 0.2 W/kg for females (main effects for terrain, sex and interaction, all P < 0.001). The males were 20% faster than the females on the uphill video section (16 ± 1 versus 13 ± 1 km/h, P < 0.001, ES = 2.6), with 95% of the male skiers and 21% of the female skiers using gear 3 exclusively, and the remaining skiers using gear 2 exclusively or a combination of gears 2 and 3.

    CONCLUSION: The present results indicate an overall sex difference in sprint skiing performance of ~12% and reveal differences in terrain-specific pacing as well as gear choice between sexes with females showing a higher overall variation in speed and considerably slower uphill skiing.

  • 5. Bishop, David
    et al.
    Edge, Johann
    McGawley, Kerry
    Physiological responses during a 9 h sheep shearing world record attempt: A case study2005In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 8, no Supplement, p. 59-Article in journal (Refereed)
  • 6.
    Carr, Amelia
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Deakin University, Burwood, Victoria, Australia.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Govus, Andrew
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Shannon, Oliver M.
    Newcastle University, Newcastle upon Tyne, United Kingdom.
    Mattsson, Stig
    Örebro University, Örebro, Sweden.
    Melin, Anna K.
    University of Copenhagen, Copenhagen, Denmark.
    Nutritional Intake in Elite Cross-Country Skiers During Two Days of Training and Competition2019In: International Journal of Sport Nutrition & Exercise Metabolism, ISSN 1526-484X, E-ISSN 1543-2742, Vol. 29, no 3, p. 273-281Article in journal (Refereed)
    Abstract [en]

    This study investigated the energy, macronutrient and fluid intakes, as well as hydration status (urine specific gravity; USG), in elite cross-country skiers during a typical day of training (day one) and a sprint skiing competition the following day (day two). Thirty-one (18 male and 13 female) national team skiers recorded their food and fluid intakes and USG was measured on days one and two. In addition, the females completed the Low Energy Availability in Females-Questionnaire (LEAF-Q) to assess their risk of long-term energy deficiency. Energy intake for males was 65+/-9 kcal/kg on day one versus 58+/-9 kcal/kg on day two (P=0.002), and for females was 57+/-10 on day one versus 55+/-5 kcal/kg on day two (P=0.445). Carbohydrate intake recommendations of 10-12 g/kg/day were not met by 89% of males and 92% of females. All males and females had a protein intake above the recommended 1.2-2.0 g/kg on both days, and a post-exercise protein intake above the recommended 0.3 g/kg. Of the females, 31% were classified as being at risk of long-term energy deficiency. In the morning of day one, 50% of males and 46% of females were dehydrated; on day two this was the case for 56% of males and 38% of females. In conclusion, these data suggest that elite cross-country skiers ingested more protein and less carbohydrate than recommended, and one third of the females were considered at risk for long-term energy deficiency. Furthermore, many of the athletes were dehydrated prior to training and competition.

  • 7.
    Carr, Amelia
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Deakin University, Australia.
    Melin, Anna
    University of Copenhagen.
    Govus, Andrew
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Shannon, Oliver
    Leeds Beckett University, UK.
    Provis, Holly
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Karlsson, Mathilda
    Mattson, Stig
    Swedish Olympic Committee.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Nutritional intake in elite cross-country skiers during a simulated sprint race2017Conference paper (Refereed)
    Abstract [en]

    Introduction: Habitual nutritional intakes in cross-country skiers have previously been reported (Fogelholm et al., 1992), however in elite cross-country skiers there is limited knowledge about race-specific nutritional practices, or the prevalence of dehydration and persistent low energy availability (EA). This study aimed to investigate, in the context of a simulated sprint race, energy intake, macronutrient intake, hydration status and the risk of persistent low EA in elite cross-country skiers. Methods: Thirty-two male (n = 18) and female (n = 14) elite Swedish cross-country skiers completed weighed food records the day prior to (day 1) and the day of a simulated sprint race (day 2); the food records were analysed for energy (kcal/kg), macronutrient (g/kg) and fluid intake (L). Urine specific gravity (USG) was also measured on day 1 and day 2. The risk for persistent low EA was assessed in the female skiers using the Low Energy Availability in Females Questionnaire (LEAF-Q; Melin et al., 2014). Results were analysed using a three-way mixed ANOVA. Statistical significance was set to a level of p ≤ 0.05. Results: Males had a higher energy intake (65±9 kcal/kg) on day 1, (pre-race) compared with day 2 (simulated sprint race; 58±9kcal/kg; p = 0.002). Females consumed 57±10 kcal/kg on day 1, which was similar to their day 2 energy intake (54±6 kcal on day 2; p > 0.05). Males consumed less carbohydrate (8.2±2.3g/kg) on day 1 compared with day 2 (8.9±2.3g/kg) (p = 0.026), as did females, consuming 7.0±1.5g/kg on day 1, and 8.4±1.7g/kg on day 2 (p = 0.003). There were similar fluid intakes across the two days for males (p > 0.05) and females (p > 0.05). Nine of the 18 males and 6 of the 14 females were dehydrated (USG > 1.020) on day 1, and 9 males and 5 females were dehydrated on day 2. Five of the 14 females were classified as being at risk of persistent low EA. Discussion: This study provides an initial insight into nutritional competition habits in elite cross-country skiers. The findings indicate that elite skiers’ nutritional intakes are consistent with guidelines, particularly those for endurance athletes’ carbohydrate intake for competitive events (Burke et al., 2001). There was however some evidence of persistent low EA and dehydration, suggesting additional considerations that may be relevant to cross-country skiers’ nutritional intakes for sprint races.

  • 8. Dekerle, Jeanne
    et al.
    McGawley, Kerry
    Mucci, Patrick
    Carter, Helen
    Effect of hypoxia on the work-time relationship2007Conference paper (Refereed)
  • 9. Dekerle, Jeanne
    et al.
    Williams, Craig
    McGawley, Kerry
    Berthoin, Serge
    Carter, Helen
    90-s all-out test and aerobic fitness in children2006Conference paper (Refereed)
  • 10. Dekerle, Jeanne
    et al.
    Williams, Craig
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Carter, Helen
    Critical power is not attained at the end of an isokinetic 90-second all-out test in children2009In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 27, no 4, p. 379-385Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to establish whether critical power, as traditionally determined from the performance of three constant-load tests to exhaustion, is attained at the end of a 90-s all-out test in children. Sixteen healthy children (eight males and eight females; mean age 12.3 years, sx  = 0.1; body mass 39.6 kg, sx  = 1.8; peak VO2 2.0 litres · min−1, sx  = 0.1) completed an incremental test to exhaustion to determine peak oxygen uptake (peak VO2), three separate constant-load tests to exhaustion to calculate critical power, and an isokinetic 90-s all-out test. The end power of the 90-s test averaged over the last 10 s (140 W, sx  = 8) was significantly higher than critical power (105 W, sx  = 6; t = 6.8; P < 0.01), yet the two parameters were strongly correlated (r = 0.74; P < 0.01). After 60 s, there were no further reductions in power output during the 90-s test (P < 0.0001). In conclusion, at the end of a 90-s all-out test, children are able to produce power outputs well above critical power. This suggests that 90 s is not long enough to completely exhaust the anaerobic work capacity in children.

  • 11.
    Govus, Andrew
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik P.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Shannon, Oliver M.
    Newcastle University, UK.
    Provis, Holly
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Karlsson, Mathilda
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Commercially available compression garments or electrical stimulation do not enhance recovery following a sprint competition in elite cross-country skiers2018In: European Journal of Sport Science, ISSN 1746-1391, E-ISSN 1536-7290, Vol. 18, no 10, p. 1299-1308Article in journal (Refereed)
    Abstract [en]

    This study investigated whether commercially available compression garments (COMP) exerting a moderate level of pressureand/or neuromuscular electrical stimulation (NMES) accelerate recovery following a cross-country sprint skiing competitioncompared with a control group (CON) consisting of active recovery only. Twenty-one senior (12 males, 9 females) and 11junior (6 males, 5 females) Swedish national team skiers performed an outdoor sprint skiing competition involving foursprints lasting ∼3–4 min. Before the competition, skiers were matched by sex and skiing level (senior versus junior) andrandomly assigned to COMP (n = 11), NMES (n = 11) or CON (n = 10). Creatine kinase (CK), urea, countermovementjump (CMJ) height, and perceived muscle pain were measured before and 8, 20, 44 and 68 h after competition. NeitherCOMP nor NMES promoted the recovery of blood biomarkers, CMJ or perceived pain post-competition compared withCON (all P > .05). When grouping all 32 participants, urea and perceived muscle pain increased from baseline, peaking at8 h (standardised mean difference (SMD), [95% confidence intervals (CIs)]): 2.8 [2.3, 3.2]) and 44 h (odds ratio [95%CI]: 3.3 [2.1, 5.1]) post-competition, respectively. Additionally, CMJ was lower than baseline 44 and 68 h postcompetitionin both males and females (P < .05). CK increased from baseline in males, peaking at 44 h (SMD: 1.4 [−0.4,0.9]), but was decreased in females at 20 h post-competition (SMD: −0.8 [−1.4, −0.2]). In conclusion, cross-countrysprint skiing induced symptoms of exercise-induced muscle damage peaking 8–44 h post-competition. However, neitherCOMP nor NMES promoted physiological or perceptual recovery compared with CON.

  • 12.
    Govus, Andrew
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Shannon, Oliver
    Provis, Holly
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Karlsson, Mathilda
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Compression garments and electrical stimulation do not enhance recovery from a cross-country sprint skiing competition2017Conference paper (Refereed)
    Abstract [en]

    Purpose: To investigate whether compression garments (CG) and neuromuscular electrical stimulation (NMES) augment post-race recovery compared with a passive control group (CON) following a cross-country sprint skiing competition. Methods: Twenty-one senior (12 males, 9 females) and 11 junior (6 males, 5 females) Swedish national team skiers performed a sprint skiing competition involving four, ~3-4 min sprints. After the race, skiers were matched by sex and skiing level (senior versus junior) and randomly assigned to a CON (n = 10), CG (n = 11) or NMES group (n = 11). Creatine kinase (CK) and urea, countermovement jump height (CMJ) and perceived sleep duration, sleep quality and muscle pain were measured before and 8, 20, 44 and 68 h after the race to assess the efficacy of each recovery intervention. Results: Neither CG nor NMES promoted the recovery of blood biomarkers, perceived wellness nor CMJ post-race compared with the passive control group (all P < 0.05). When grouping all 32 participants, CK, urea and muscle pain increased from pre-race values, peaking 20-44 h post-race (P < 0.05). CMJ was lower than pre-race values 44 and 60 h post-race in males and females (both P < 0.05). Sleep duration increased from pre-race to post-race (P < 0.05), whereas sleep quality was unchanged (P > 0.05). Conclusion: A cross-country sprint skiing competition induced symptoms of exercise-induced muscle damage peaking 20-44 h post-race. However, CG and NMES did not augment the recovery of physiological, perceptual or performance parameters compared with a passive control group after the sprint skiing competition.

  • 13.
    Jonsson, Malin
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Laaksonen, Marko
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Rifle carriage decreases speed at lactate threshold, anaerobic energy contribution and performance in biathlon skiing.2019Conference paper (Refereed)
    Abstract [en]

    Biathlon is an endurance sport combining rifle shooting and intermittent cross-country skiing while carrying a rifle (minimum weight 3.5 kg). Previous studies have shown that the skiing component explains 60% of overall biathlon performance (1) and that rifle carriage affects different physiological responses such as blood lactate, oxygen uptake (VO2) and heart rate during skiing (2, 3). However, the effects of rifle carriage on skiing performance and variables such as maximal VO2 (VO2max), lactate threshold, efficiency of movement and anaerobic energy contribution have not yet been investigated.METHODS:Seventeen biathletes (9 females, 8 males; age 23.0 (3.3) years, VO2max 59.8 (7.3) mL/kg/min), competing at a national and/or international level, and completing approximately three biathlon training sessions/week with the rifle on the back, performed a submaximal incremental test and a 900–1000-m maximal time-trial (TT) using treadmill roller-skiing (gear 3 skating technique) on two occasions separated by at least 48 hours. One condition involved carrying the rifle on the back (WR) and the other no rifle (NR), with the order randomized. The VO2 and skiing speed at 4 mmol/L of blood lactate (VO2@4mmol and speed@4mmol, respectively), gross efficiency (GE), metabolic aerobic (MRae) and anaerobic (MRan) rates, and VO2max were determined. RESULTS:Submaximal VO2 at all levels and GE (16.7 (0.9) vs 16.5 (1.1) %, p<0.05) were higher for WR compared to NR, while speed@4mmol (11.3 (1.5) vs 11.7 (1.5) km/h, p<0.05) and MRan (27.3 (6.7) vs 30.5 (7.6) kJ/min, p<0.01) was lower. There were no differences in VO2@4mmol or MRae between the two conditions. The mean speed during the TT was higher for NR compared to WR (16.5 (1.5) vs 15.5 (1.4) km/h, p<0.001), but there was no difference in VO2max. Mean speed during the TT was correlated to speed@4mmol (WR: r=0.810, p<0.001; NR: r=0.659, p<0.01), GE (WR: r=0.691; NR r=0.529, both p<0.05) and VO2max (WR: r=0.514; NR: r=0.526, both p<0.05). Speed@4mmol together with MRan explained more than 80% of performance in the TT (WR 83.7%, NR 81.5%). There was no difference between male and female biathletes in response to rifle carriage, although the relative mass of the rifle was higher for the females (5.6 (0.4) vs 5.0 (0.4) % of body mass, p<0.01).CONCLUSION:According to this study, the most important variables for skiing speed in biathlon seem to be the speed at lactate threshold combined with the metabolic anaerobic rate, both of which were lower for skiing with the rifle compared to without. In addition, GE was related to biathlon performance and was also affected by rifle carriage. Thus, to improve skiing performance in biathlon, improving speed at the lactate threshold, anaerobic energy delivery and GE while carrying the rifle are recommended.

  • 14.
    Karlsson, Øyvind
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Laaksonen, Marko
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Training characteristics of highly-trained cross-country skiers throughout the transition from junior to senior level2019Conference paper (Refereed)
    Abstract [en]

    INTRODUCTION: Reaching an international level in any endurance sport requires a large volume of systematic training performed over time. While the annual training characteristics of senior, elite-level cross-country (XC) skiers are well documented (1), limited data exist regarding the long-term training of developing XC skiers. The current study aimed to describe the training undertaken by a group of highly-trained XC skiers throughout their transition from junior- to senior-level athletes. METHODS: In this retrospective cohort study, self-reported training data were obtained from 32 highly-trained female (n = 13) and male (n = 19) XC skiers for the season they turned 16 years old (y) until the season they turned 23 y. At the time of inclusion, 26 skiers (11 females and 15 males) had represented at least one of the Swedish national teams (senior, development or junior), and eight of these skiers (6 females and 2 males) had won at least one individual U23 or Junior World Championship medal. The remaining six skiers were part of a specialist ski university in Sweden, where selection is based on the potential to perform at a world-class level. Training data were organized by training form (endurance, strength, and speed), mode (e.g. on-snow skiing, roller skiing, running, and cycling), and intensity (using a 4-zone model), which were then divided into five annual training phases (transition, general preparation [GP], specific preparation [SP], competition [CP], regeneration). RESULTS: Data from 155 seasons, including 59 026 individual training sessions and 94 964 h of training, were analysed. From age 16 to 22 y the total volume of endurance training increased from 472 ± 70 to 721 ± 86 h/yr (p < 0.001). Low-intensity training (LIT, below the first lactate threshold, <85% HRmax) and high-intensity training (HIT, above the first lactate threshold, >85% HRmax) increased from 414 ± 61 to 656 ± 72 h/yr (p < 0.001) and 58 ± 33 to 65 ± 16 h/yr (p = 0.018), respectively. The training-volume distribution developed progressively from a more even distribution across training phases at age 16 y (GP: 10.6 ± 1.8 h/wk; SP: 10.4 ± 1.5 h/wk; CP: 8.6 ± 1.5 h/wk) to a more traditional periodised model at age 22 y (GP: 17.5 ± 1.7 h/wk; SP: 12.7 ± 1.9 h/wk; CP: 11.1 ± 2.1 h/wk), whereby a higher proportion of the total training volume was performed in GP, and a lower proportion in SP and CP, as athletes developed. CONCLUSION: In conclusion, this group of highly-trained XC skiers progressively increased their endurance training volume from age 16 to 22 y, to a level that is required of elite XC skiers. This increase in training volume was primarily due to an increase in LIT in the general preparation phase. In addition, training-volume distribution became more periodised as athletes developed from junior to senior level. REFERENCES 1. Ø. Sandbakk & HC. Holmberg, International Journal of Sports Physiology and Performance 9, 117-121 (2014).

  • 15.
    Laaksonen, Marko
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Jonsson, Malin
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Laboratory-based factors predicting performance in biathlon skiing2017Conference paper (Refereed)
  • 16. Leclair, Erwan
    et al.
    Mucci, Patrick
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Berthoin, Serge
    Application of the critical power concept in different populations2008In: Science & sports, ISSN 0765-1597, E-ISSN 1778-4131, Vol. 23, no 5, p. 206-215Article in journal (Refereed)
    Abstract [en]

    Aim. – The aim of this review was to state the use of critical power concept at different populations and to summarize studies reported data inorder to highlight its interest for the aerobic abilities assessement. Conclusion. – The critical power determination is based on times to exhaustion at different exercise intensities. The synthesis of several studiesshowed that this concept allows to discriminate populations relatively to their aerobic abilities. This is confirmed by its correlation to maximaloxygen uptake and ventilatory threshold in age and fitness different populations.

  • 17.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Field-based analyses in cross-country skiing and biathlon2019Conference paper (Other academic)
  • 18. McGawley, Kerry
    Responses at and around critical power2007Conference paper (Other (popular science, discussion, etc.))
  • 19.
    McGawley, Kerry
    University of Brighton.
    The application of the Critical Power construct to endurance exercise2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Critical power (CP) is a theoretical construct reflecting the highest work rate that can be maintained by continuous aerobic energy resynthesis for an infinite period of time.  In practice, however, the CP estimate derived from mathematical modelling usually leads to exhaustion within 1 h.  While previous research has used traditional measures of aerobic fitness to validate CP, there is disagreement in the literature as to whether CP reflects a physiological steady or a non-steady state.  Furthermore, the practical applications of the CP construct have received limited research attention.  Therefore, the purpose of this thesis was to clarify the applicability of CP to endurance exercise.

    Following experimentation for measurement reliability and equipment validation, two experimental studies formed the core of the thesis work.  In the first of these two studies, participants were grouped by their peak aerobic power (VO2peak) as either low (LOW: 26.8 – 40.6 mL∙kg-1∙min-1, n = 9), moderate (MOD: 43.6 – 49.6 mL∙kg-1∙min-1, n = 8) or high (HIGH: 57.8 – 69.0 mL∙kg-1∙min-1, n = 8) fitness.  The relationships between CP and traditional measures of aerobic fitness (e.g., lactate threshold, VO2peak and maximal minute power) were found to be similar for all fitness groups.  Furthermore, VO2, blood lactate concentration and heart rate continued to rise over time during exercise at CP for all groups.

    In the second main study, recreationally active participants were randomly assigned to groups that trained for six weeks either below CP (<CP, n = 14), at CP (CP, n = 15) or intermittently around CP (CPINT, n = 14).  Total work was matched between groups and training time was significantly shorter for the CP group compared with the <CP and CPINT groups.  While all training interventions resulted in significant increases in CP and other measures of aerobic fitness (e.g., lactate threshold, economy, VO2peak and muscle enzyme content), there were no interaction effects between groups.  In summary, CP was shown to reflect an unstable physiological state, irrespective of fitness status, that is responsive to continuous and intermittent training and may be used as a time-efficient training intensity improving aerobic fitness.

  • 20.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The reliability and validity of a four-minute running time-trial in assessing VO2max and performance2017In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, no MAY, p. 1-9, article id 270Article in journal (Refereed)
    Abstract [en]

    Introduction: Traditional graded-exercise tests to volitional exhaustion (GXTs) are limited by the need to establish starting workloads, stage durations, and step increments. Short-duration time-trials (TTs) may be easier to implement and more ecologically valid in terms of real-world athletic events. The purpose of the current study was to assess the reliability and validity of maximal oxygen uptake (VO2max) and performance measured during a traditional GXT (STEP) and a four-minute running time-trial (RunTT). Methods: Ten recreational runners (age: 32 ± 7 years; body mass: 69 ± 10 kg) completed five STEP tests with a verification phase (VER) and five self-paced RunTTs on a treadmill. The order of the STEP/VER and RunTT trials was alternated and counter-balanced. Performance was measured as time to exhaustion (TTE) for STEP and VER and distance covered for RunTT. Results: The coefficient of variation (CV) for VO2max was similar between STEP, VER, and RunTT (1.9 ± 1.0, 2.2 ± 1.1, and 1.8 ± 0.8%, respectively), but varied for performance between the three types of test (4.5 ± 1.9, 9.7 ± 3.5, and 1.8 ± 0.7% for STEP, VER, and RunTT, respectively). Bland-Altman limits of agreement (bias ± 95%) showed VO2max to be 1.6 ± 3.6 mL·kg-1·min-1 higher for STEP vs. RunTT. Peak HR was also significantly higher during STEP compared with RunTT (P = 0.019). Conclusion: A four-minute running time-trial appears to provide more reliable performance data in comparison to an incremental test to exhaustion, but may underestimate VO2max.

  • 21.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Why does sport need science?2017Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Sport science is a relatively new academic field and has grown enormously in recent decades, particularly in terms of University programs offered, scientific publications and career opportunities. This presentation aims to clarify what sport science is, why it may be useful, how it can be implemented in practice and who are the people responsible for driving it forward. In traditional terms, sport science involves topics such as physiology, biomechanics and psychology. A more comprehensive description may also include strength and conditioning, nutrition, performance analysis, lifestyle management, etc. Nations investing more heavily in sport science at an elite level in terms of infrastructure and expertise (such as Great Britain and Australia, for example) have received significant international sporting success.

    While these sport-science institute models are certainly not perfect, they signal a strong relationship between financial investment in elite sport and ranking at an international level. A typical method for implementing sport science is via a sport scientist or practitioner, an individual (or ideally a team of individuals) who is able to understand and interpret often complex science-based principles and communicate them clearly and effectively to coaches and athletes.

    Our aim is to improve sports performance by informing practice using the most up-to-date evidence available. This relationship between science and applied sport is key, but is challenging for all parties (i.e., the researchers, practitioners, coaches and athletes). Like all relationships, it requires commitment and effort from all involved and in particular, understanding regarding each other’s different needs, priorities, strengths and limitations.

  • 22.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Per-Ivar
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Quantifying the effects of an optimised physical training programme in pre-season: does order matter?2012Conference paper (Refereed)
  • 23.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Per-Ivar
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The order of concurrent training does not affect soccer-related performance adaptations2013In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 34, no 11, p. 983-990Article in journal (Refereed)
    Abstract [en]

    Despite the wealth of evidence regarding physical training strategies in soccer, there is little information regarding soccer-specific concurrent training and the effects of training order. The current study aimed to: i) quantify the effects of concurrent high-intensity run-based training (HIT) and strength- and power-based training (STR) on soccer-specific performance, and ii) investigate the order effect of completing HIT and STR either first or second within training sessions. Eighteen semi- and fully-professional players completed a battery of field- and gym-based tests before and after a 5-week pre-season training intervention. Players were pair-matched and completed 3 sessions per week of HIT followed by STR (n=9) or STR followed by HIT (n=9). ANCOVA tests revealed no differences between groups for changes in any of the measures (p>0.05). However, a training effect was observed for all measures (p<0.05), with 10-m sprint, 6×30-m repeated sprint, 40-m agility and Yo-Yo test performances improving by 1.8±2.6%, 1.3±1.8%, 1.0±1.5% and 19.4±23.4%, respectively (n=18). In conclusion, there was a positive effect of the concurrent training approach on key measures of soccer performance, but the order of completing HIT and STR appears inconsequential to performance adaptations.

  • 24. McGawley, Kerry
    et al.
    Bishop, David
    Anaerobic and aerobic contribution to two, 5 x 6-s repeated-sprint bouts2008In: Coaching and Sport Science Journal, Vol. 3, no 2, p. 52-Article in journal (Refereed)
  • 25.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. School of Sport Science, Exercise and Health, The University of Western Australia, Australia.
    Bishop, David
    School of Sport Science, Exercise and Health, The University of Western Australia, Australia.
    Oxygen uptake during repeated-sprint exercise2015In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 18, no 2, p. 214-218Article in journal (Refereed)
    Abstract [en]

    Objectives

    Repeated-sprint ability appears to be influenced by oxidative metabolism, with reductions in fatigue and improved sprint times related to markers of aerobic fitness. The aim of the current study was to measure the oxygen uptake (VO2) during the first and last sprints during two, 5 x 6-s repeated-sprint bouts.

    Design

    Cross-sectional study.

    Methods

    Eight female soccer players performed two, consecutive, 5 x 6-s maximal sprint bouts (B1 and B2) on five separate occasions, in order to identify the minimum time (trec) required to recover total work done (Wtot) in B1. On a sixth occasion, expired air was collected during the first and last sprint of B1 and B2, which were separated by trec.

    Results

    The trec was 10.9 ± 1.1 min. The VO2 during the first sprint was significantly less than the last sprint in each bout (p < 0.001), and the estimated aerobic contribution to the final sprint (measured in kJ) was significantly related to VO2max in both B1 (r = 0.81, p = 0.015) and B2 (r = 0.93, p = 0.001). In addition, the VO2 attained in the final sprint was not significantly different from VO2max in B1 (p = 0.284) or B2 (p = 0.448).

    Conclusions

    The current study shows that the VO2 increases from the first to the last of 5 x 6-s sprints and that VO2max may be a limiting factor to performance in latter sprints. Increasing VO2max in team-sport athletes may enable increased aerobic energy delivery, and consequently work done, during a bout of repeated sprints.

  • 26. McGawley, Kerry
    et al.
    Bishop, David
    Reliability of a 5 x 6-s maximal cycling repeated-sprint test in trained female team-sport athletes2006In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 98, no 4, p. 383-393Article in journal (Refereed)
    Abstract [en]

    The present study examined the reliability of work and power measures during a 5 × 6-s cycle ergometer test of repeated-sprint ability. Nine, well-trained, female soccer players performed five, 5 × 6-s repeated-sprint tests on a front-access cycle ergometer on separate days. Sprints were separated by 24 s of active recovery. Absolute measures of total work done (W tot), total peak power (PPtot), work done during sprint 1 (W 1) and peak power output during sprint 1 (PP1) were recorded. Decrement scores in work done (W dec) and peak power output (PPdec), and fatigue indices for work done (FI W ) and peak power (FI P ), were calculated. Significant improvements in all of the work and power measures were observed between trial 1 and subsequent trials (P < 0.05), but no significant differences were identified between trials 2, 3, 4 and 5. The same was true for increases in the decrement scores. The coefficient of variation (CV) was established to reflect within-subject reproducibility for each variable. The CV was significantly improved by the third trial for work done (W tot CV: trials 1–2 = 5.5%; trials 3–4 = 2.8%), peak power (PPtot CV: trials 1–2 = 5.1%; trials 3–4 = 2.7%) and performance decrement scores (P < 0.05). The standard error of measurement (SEM) and intraclass correlation coefficient (ICC) were also calculated for each variable and expressed within 95% confidence intervals. It was concluded that two familiarisation trials are optimal for collecting reliable data from a 5 × 6-s repeated-sprint cycling test. Furthermore, due to the large variation around performance decrement it was suggested that decrement scores ought to be interpreted with caution.

  • 27. McGawley, Kerry
    et al.
    Bishop, David
    Edge, Johann
    The physiological determinants of recovering repeated-sprint ability in team-sport athletes2005Conference paper (Refereed)
  • 28. McGawley, Kerry
    et al.
    Dekerle, Jeanne
    Brickley, Gary
    Carter, Helen
    Critical power in groups with different peak oxygen uptake2007Conference paper (Refereed)
  • 29.
    McGawley, Kerry
    et al.
    University of Brighton, United Kingdom.
    Edge, Johann
    University of Brighton, United Kingdom.
    Bishop, David
    University of Brighton, United Kingdom.
    The recovery of repeated-sprint performance occurs before the full recovery of muscle lactate and phosphocreatine2006In: , 2006Conference paper (Refereed)
    Abstract [en]

    Single and repeated-sprint protocols result in significant rises in blood and muscle lactate (La-bl and La-m), and significant decreases in muscle pH (pHm) and phosphocreatine (PCr)(1,2). High correlations have been demonstrated between the percentage restoration of power during a second 30-s sprint and the percentage resynthesis of PCr, while neither pHm or La-m recovery were related to the recovery of 30-s sprint performance(1). To date, however, no study has investigated the relationship between the recovery of muscle metabolites and the recovery of repeated-sprint performance. Furthermore, no study has investigated metabolite concentrations at a point when subsequent performance is fully recovered. The aim of the present study was to identify the relationships between performance recovery and the recovery of muscle metabolites, La-bl and oxygen consumption (VO2) following 5 x 6-s repeated-sprint exercise. Nine female soccer players (mean ± SD: age 27 ± 7 y; mass 60.5 ± 5.3 kg; VO2max 50.0 ± 3.9 mL/kg/min) performed two consecutive 5 x 6-s maximal sprint-cycle bouts (B1 and B2) on eight separate occasions. The five sprints within each bout were separated by 24 s of active recovery and the two bouts were separated by passive recovery periods lasting 5 – 14 min. Trials 1 – 6 were used to identify the least time required to recover total work done (Wtot) over a 5 x 6-s bout (time = trec). During trial 7, expired air was collected between B1 and B2(separated by trec). During trial 8, blood samples and v. lateralis muscle biopsies were taken at rest, immediately post B1 and at theindividual trec. Following trec (mean ± SD: 10.7 ± 1.2 min), Wtot recovered to 100 ± 1.05 % (B1: 18575 ± 1792 J, B2: 18579 ± 1861 J; P=0.947).La-bl was higher than at rest both immediately post B1 and after trec (11.6 ± 3.2 and 10.9 ± 4.6 vs 1.0 ± 0.5 mmol/L; P<0.001). pHmdropped during B1 (7.1 ± 0.1 to 6.9 ± 0.1; P<0.01) and recovered to 7.1 ± 0.1 at trec (not different from rest, P>0.1). La-m content was elevated above the resting value post B1 (95.0 ± 54.7 vs 14.4 ± 1.6 mmol/L; P<0.05) and dropped significantly during recovery, remaining higher than the resting value (38.0 ± 16.4 mmol/L; P<0.05). PCr was reduced to 43 ± 22 % of resting content following B1 and despite recovering to 82 ± 13 %, remained lower than baseline PCr content after trec. During recovery from B1, VO2 was unchanged (i.e., hadstabilised) after 3.0 min (P>0.05). Results suggest that the full recovery of La-bl, La-m and PCr is not necessary for the recovery of 5 x 6-ssprint performance in trained, female, team-sport athletes. Instead it may be more important for pHm to have returned to baseline levels and for sufficient PCr resynthesis to have occurred to recover work in a second bout. 1. Bogdanis G., et al. (1995). J Physiol 482(2): 467-480; 2. Bishop D., et al. (2004). Eur J Appl Physiol 92: 540-547. The first author’s position is supported by the EU-funded Interreg IIIa programme.

  • 30.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Aerobic and anaerobic contributions to energy production among junior male and female cross-country skiers during diagonal skiing2014In: International Journal of Sports Physiology and Performance, ISSN 1555-0265, E-ISSN 1555-0273, Vol. 9, no 1, p. 32-40Article in journal (Refereed)
    Abstract [en]

    Purpose: Cross-country-ski races place complex demands on athletes, with events lasting between approximately 3 min and 2 h. The aim of the current study was to compare the aerobic and anaerobic measures derived from a short time trial (TT) between male and female skiers using diagonal cross-country skiing. Methods: Twenty-four highly trained cross-country skiers (12 male and 12 female, age 17.4 ± 1.4 y, body mass 68.2 ± 8.9 kg, height 174 ± 8 cm) participated. The submaximal VO2–speed relationship and VO2max were derived from an incremental ramp test to exhaustion (RAMP), while the accumulated oxygen deficit (AOD), peak VO2, and performance time were measured during a 600-m TT. Results: The female skiers took longer to complete the TT than the males (209 ± 9 s vs 166 ± 7 s, P < .001) and exhibited a lower relative anaerobic contribution (20% ± 4% vs 24% ± 3%, P = .015) and a higher fractional utilization of VO2max (84% ± 4% vs 79% ± 5%, P = .007) than males. Although there was no significant difference in AOD between the sexes (40.9 ± 9.5 and 47.3 ± 7.4 mL/kg for females and males, respectively; P = .079), the mean difference ± 90% confidence intervals of 6.4 ± 6.0 mL/kg reflected a likely practical difference (ES = 0.72). The peak VO2 during the TT was significantly higher than VO2max during the RAMP for all participants combined (62.3 ± 6.8 vs 60.5 ± 7.2 mL/kg/min, P = .011), and the mean difference ± 90% confidence intervals of 1.8 ± 1.1 mL/kg reflected a possible practical difference (ES = 0.25). Conclusions: These results show that performance and physiological responses to a self-paced TT lasting approximately 3 min differ between sexes. In addition, a TT may provide a valid measure of VO2max.

  • 31.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Juudas, Elisabeth
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Block interval training in highly-trained cross-country skiers2013In: Proceedings for the 6th International Congress on Science and Skiing / [ed] Erich Mueller, Josef Kröll, Stefan Josef Lindinger, Jurgen Pfusterschmied, Thomas Stöggl, 2013, p. 83-Conference paper (Refereed)
    Abstract [en]

    INTRODUCTION: Short periods of intensified training elicit symptoms of overreaching within only 7 days (Halson et al. 2002). Despite this, block periodization of high-intensity interval training (HIT) has led to superior aerobic responses compared with traditional endurance training among trained alpine skiers and cyclists (Breil et al. 2010; Rønnestad et al. 2012).

    METHODS: 21 highly-trained junior cross-country skiers (10 males, 11 females; age 16-20 y) completed 2 x 3-week training blocks in a randomized crossover design, whereby the training sessions in each 3-week block were identical but the distribution of HIT and low-intensity training (LIT) was different. In traditional periodization (TP), 3 HIT sessions (5 x 4-min at >90% HRmax) were completed each week, with LIT sessions evenly distributed over the 3-week period. In block periodization (BP) the same 9 HIT sessions were completed in week 2 and only LIT sessions were completed in weeks 1 and 3. REST-Q data was collected after each training week while resting saliva sampling (for determination of IgA and cortisol), incremental tests and performance trials were completed pre and post each 3-week period.

    RESULTS: Although the overall training load (P=0.651) and total amount of work performed during HIT sessions (P=0.224) did not differ between TP and BP, the session RPE was higher and perceived recovery was lower in connection with the HIT sessions during BP (P<0.001). In addition, sport-specific stress REST-Q scores were higher following the BP-HIT week compared with all other weeks (P<0.008), whereas the global recovery-stress state was similar between all TP and BP weeks (P>0.05). Pre to post changes in salivary IgA and cortisol were also similar for TP and BP (P>0.05), although there was a tendency for IgA and cortisol to increase after TP (ES: 0.75 and 0.37) and decrease after BP (ES: 0.23 and 0.12, respectively). The change in VO2max was greater following TP versus BP (2±4% vs -1±3%; P=0.043), whereas the changes in economy (i.e., sub-maximal VO2) and 600-m time-trial performance did not differ between TP and BP (P>0.05).

    DISCUSSION: The current study shows that highly-trained junior cross-country skiers are able to complete 9 HIT sessions at >90% HRmax within a week, with no difference in work done during the HIT sessions compared to a more traditional format of HIT-session distribution. Moreover, the REST-Q and biochemical markers indicate that BP does not lead to greater overall stress compared with TP, despite acute increases in stress following the BP-HOT week. Unlike previous studies using alpine skiers and cyclists (Breil et al. 2010; Rønnestad et al. 2012), the current findings do not support BP as a superior method for improving aerobic characteristics or performance among highly-trained cross-country skiers.

    CONCLUSION: The BP intervention introduced in the current study can be tolerated by junior cross-country skiers in a highly-trained state and may be a useful training method at different stages of the season. However, it does not appear superior to TP in inducing aerobic or performance adaptations.

  • 32.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Juudas, Elisabeth
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Kazior, Zuzanna
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.
    Ström, Kristoffer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Lunds Universitet.
    Blomstrand, Eva
    Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.
    Hansson, Ola
    Lunds Universitet.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    No additional benefits of block-over evenly-distributed high-intensity interval training within a polarized microcycle2017In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, no JUN, p. 1-12, article id 413Article in journal (Refereed)
    Abstract [en]

    Introduction: The current study aimed to investigate the responses to block- versus evenly-distributed high-intensity interval training (HIT) within a polarized microcycle. Methods: Twenty well-trained junior cross-country skiers (10 males, age 17.6 ± 1.5 and 10 females, age 17.3 ± 1.5) completed two, 3-week periods of training (EVEN and BLOCK) in a randomized, crossover-design study. In EVEN, 3 HIT sessions (5 × 4-min of diagonal-stride roller-skiing) were completed at a maximal sustainable intensity each week while low-intensity training (LIT) was distributed evenly around the HIT. In BLOCK, the same 9 HIT sessions were completed in the second week while only LIT was completed in the first and third weeks. Heart rate (HR), session ratings of perceived exertion (sRPE), and perceived recovery (pREC) were recorded for all HIT and LIT sessions, while distance covered was recorded for each HIT interval. The recovery-stress questionnaire for athletes (RESTQ-Sport) was completed weekly. Before and after EVEN and BLOCK, resting saliva and muscle samples were collected and an incremental test and 600-m time-trial (TT) were completed. Results: Pre- to post-testing revealed no significant differences between EVEN and BLOCK for changes in resting salivary cortisol, testosterone, or IgA, or for changes in muscle capillary density, fiber area, fiber composition, enzyme activity (CS, HAD, and PFK) or the protein content of VEGF or PGC-1α. Neither were any differences observed in the changes in skiing economy, VO2max or 600-m time-trial performance between interventions. These findings were coupled with no significant differences between EVEN and BLOCK for distance covered during HIT, summated HR zone scores, total sRPE training load, overall pREC or overall recovery-stress state. However, 600-m TT performance improved from pre- to post-training, irrespective of intervention (P = 0.003), and a number of hormonal and muscle biopsy markers were also significantly altered post-training (P < 0.05). Discussion: The current study shows that well-trained junior cross-country skiers are able to complete 9 HIT sessions within 1 week without compromising total work done and without experiencing greater stress or reduced recovery over a 3-week polarized microcycle. However, the findings do not support block-distributed HIT as a superior method to a more even distribution of HIT in terms of enhancing physiological or performance adaptions.

  • 33.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Leclair, Erwan
    Univ Lille, Fac Sports Sci & Phys Educ, Lab Human Movement Studies, Ronchin, France.
    Dekerle, Jeanne
    Univ Brighton, Chelsea Sch Res Ctr, Eastbourne, England.
    Carter, Helen
    Univ Brighton, Chelsea Sch Res Ctr, Eastbourne, England.
    Williams, Craig
    Univ Exeter, Childrens Hlth & Exercise Res Ctr, Exeter, Devon, England.
    A test to assess aerobic and anaerobic parameters during maximal exercise in young girls2012In: Pediatric Exercise Science, ISSN 0899-8493, E-ISSN 1543-2920, Vol. 24, no 2, p. 262-274Article in journal (Refereed)
    Abstract [en]

    The Wingate cycle test (WAnT) is a 30-s test commonly used to estimate anaerobic work capacity (AWC). However, the test may be too short to fully deplete anaerobic energy reserves. We hypothesized that a 90-s all-out isokinetic test (ISO_90) would be valid to assess both aerobic and anaerobic capacities in young females. Eight girls (11.9 ± 0.5 y) performed an exhaustive incremental test, a WAnT and an ISO_90. Peak VO2 attained during the ISO_90 was significantly greater than VO2peak. Mean power, end power, fatigue index, total work done and AWC were not significantly different between the WAnT and after 30 s of the 90-s test (i.e., ISO_30). However, 95% limits of agreement showed large variations between the two tests when comparing all anaerobic parameters. It is concluded that an ISO-90 may be a useful test to assess aerobic capacity in young girls. However, since the anaerobic parameters derived from the ISO_30 did not agree with those derived from a traditional WAnT, the validity of using an ISO_90 to assess anaerobic performance and capacity within this population group remains unconfirmed.

  • 34. McGawley, Kerry
    et al.
    Leclair, Erwan
    Dekerle, Jeanne
    Williams, Craig
    Carter, Helen
    Assessing aerobic and anaerobic power from a 90-s all-out isokinetic test versus the Wingate test in young female soccer players2007In: Journal of Sports Science and Medicine (JSSM), ISSN 1303-2968, Vol. 6, no 10, p. 130-Article in journal (Refereed)
  • 35.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Nybäck, Linn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Glännerud, Caroline
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Larsson, Gustav
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Weitzberg, Eddie
    Effects of acute nitrate supplementation during cross-country roller-skiing in normobaric hypoxia2016Conference paper (Refereed)
    Abstract [en]

    Introduction:

    Supplementation with beetroot juice (BR), which is rich in inorganic nitrate (NO3-), has received considerable attention due to its beneficial effects on several physiological functions. For example, BR has led to lowered resting blood pressure (BP) and a reduced oxygen (O2) cost during moderate-intensity exercise in healthy individuals, as well as improved maximal performance (1). Similar beneficial effects in athletes are less clear (2). The anaerobic reduction of NO3- to nitrite (NO2-) in the oral cavity increases the bioavailability of nitric oxide (NO), which is thought to explain the ergogenic effect of BR. Since NO is generally produced endogenously using O2 and multiple cofactors (3), any reduction in O2 availability would attenuate this NO-pathway. Therefore, BR supplementation is believed to have a more pronounced effect in hypoxia (H). The aim of the present study was to investigate the effects of BR supplementation in competitive cross-country skiers exercising in normoxia (N) and H.

     

    Methods:

    Using a randomised crossover design, eight competitive cross-country skiers (5 males: age 22 +/- 3 y, body mass 74 +/- 8 kg, VO2max 5.2 +/- 0.4 L/min; 3 females: age 21 +/- 1 y, body mass 63 +/- 6 kg, VO2max 3.7 +/- 0.5 L/min;) supplemented with a single dose of NO3- (ca 13 mmol) or placebo (PL) performed two, 6-min submaximal exercise bouts and a 1000-m time-trial (TT) in N and H (16.8% O2). All tests were conducted on roller skis at a 6-degree incline using the diagonal-stride technique. Resting BP, blood O2 saturation (SpO2), VO2, respiratory exchange ratio (RER), heart rate (HR), rating of perceived exertion (RPE), blood lactate (La-) and time to complete the 1000-m TT (TTtime) were measured.

     

    Results:

    Plasma NO3- and NO2- levels were significantly higher following BR compared to PL (p < 0.001). However, resting BP, submaximal exercise variables and TTtime were unaffected by supplementation (p > 0.05). The VO2max obtained during the TT was significantly lower with BR in N (p < 0.05, small effect size d < 0.2), but not H.

     

    Discussion:

    Previous studies have shown beneficial effects of NO3- supplementation among well-trained athletes (4). In addition, individuals showing no effects of NO3- supplementation in N have nevertheless shown improved exercise tolerance in H (5). These findings were not reproduced in the current study, with no improvements in submaximal VO2 or TTtime following BR supplementation in N or H.

     

    Conclusion:

    BR supplementation does not improve submaximal exercise economy or 1000-m TT performance in competitive cross-country skiers exercising in normoxic or hypoxic conditions.

     

    References:

    1. Vanhatalo et al. 2010. Am J Physiol Regul Integr Comp Physiol. 299:R1121-31

    2. Peacock et al. 2012. Med Sci Sports Exerc. 44:2213-19

    3. Lundberg et al. 2015. Nat Rev Drug Discov. 14:623-41

    4. Lansley et al. 2011. Med Sci Sports Exerc. 43:1125-31

    5. Kelly et al. 2014. Am J Physiol Regul Integr Comp Physiol. 307:R920-30

  • 36.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Platt, Simon
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Beaven, Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Björklund, Glenn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The validity and reliability of a four-minute running time trial in assessing VO2max and performance2015Conference paper (Refereed)
    Abstract [en]

    INTRODUCTION: Incremental tests to volitional exhaustion are widely used to assess VO2max. However, the need to establish starting workloads, stage durations, and step increments make administration problematic. Moreover, the validity of such tests has been questioned (Beltrami et al., 2012, Br J Sports Med, 46:23-29; Mauger & Sculthorpe, 2012, Br J Sports Med, 46:59-63). Short time trials represent a simpler and more ecologically valid alternative to assess VO2max and performance across exercise modes (Crouter et al., 2001, Med Sci Sports Exerc, 33:644-647; Ansley et al., 2004, Med Sci Sports Exerc, 36:1819-1825; McGawley & Holmberg, 2014, Int J Sports Physiol Perform 9:32-40). The aim of the current study was to assess the reliability and validity of a treadmill running time trial (RunTT) for the assessment of VO2max and performance.

     

    METHODS: Ten recreational athletes (5 males, 5 females; 32 ± 7 y) completed five incremental tests to exhaustion (INC) including a verification phase (VER) on a treadmill and five, 4-min RunTTs. The order of INC+VER and RunTT trials was alternated and counter-balanced. The INC and VER protocols were externally controlled, with incline increasing by 1% every minute during the INC. By contrast, the RunTT protocol was athlete controlled, with running speed self-adjusted via a laser system fitted to the treadmill (and incline fixed at 1%). Performance was measured as time to exhaustion for INC and VER and distance covered for RunTT. Heart rate (HR) was monitored continuously throughout each protocol. RPE and lactate were assessed immediately post-exercise and at 1-min intervals for four minutes post-exercise, respectively.

     

    RESULTS: The CV for VO2max was not significantly different between INC, VER and RunTT (1.9, 2.2 and 1.7%, respectively) but for performance was significantly different between all types of test (4.5, 9.7 and 1.8% for INC, VER and RunTT, respectively; P<0.005). VO2max was significantly higher for INC compared with VER and RunTT (59.2 versus 58.0 and 57.6 mL/kg/min, respectively; P<0.001) and Bland-Altman limits of agreement showed a bias ± 95% of 1.5 ± 3.1 mL/kg/min for INC versus RunTT. Peak HR was also significantly higher for INC compared with RunTT (181 versus 177 beats/min; P<0.001), while peak RER and RPE were not different. Peak lactate was higher after RunTT compared with INC (10.13 versus 9.22 mmol/L; P<0.001).

     

    CONCLUSION: A RunTT appears to provide more reliable performance data in comparison to INC; however, VO2max values were ~ 1.5 mL/kg/min lower and peak lactate was significantly higher.

  • 37. McGawley, Kerry
    et al.
    Shannon, Oliver
    The effect of carbohydrate feeding during cycling on run performance within a simulated Olympic-distance triathlon2010In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 13, no 6, p. e38-Article in journal (Refereed)
    Abstract [en]

    Introduction: The purpose of the present study was to examine the effects of carbohydrate ingestion during the cycle leg of a simulated Olympic-distance triathlon (1500-m swim, 40-km cycle, 10-km run) on subsequent running performance. Methods: Five well-trained triathletes (4 male, 1 female) volunteered to participate (mean±SD age: 23.6±4.2 y, body mass: 63.0±7.6 kg and VO2max: 64.0±9.0 ml kg-1 min-1). Participants attended three separate testing sessions separated by at least five days. The first session involved a 1500-m swim time-trial (STT) followed approximately 30 min later by a graded cycle test to exhaustio nfor the evaluation of maximal aerobic power (MAP). The two subsequent sessions required participants to complete a simulated Olympic-distance triathlon involving a 1500-m pool swim to within 5% of the STT, a 40-km stationary cycle at 75% of MAP and a 10-km running time trial. Participants randomly consumed either a 14.4% carbohydrate drink containing 1.2 g min-1 of glucose and 0.6 g min-1 of fructose (CHO) or a fruit squash placebo (PLA) throughout the cycle leg of the triathlon. Fingertip blood samples were collected after every 5 km of the cycle leg and at the end of the run and were subsequently analysed for blood glucose (GLU) and lactate (LAC) concentrations. Rating of perceived exertion (RPE) and perceived stomach upset (PSU) were also measured after each 5-km cycle period and at the end of the run. Heart rate (HR) was measured throughout the cycle leg only. Results and conclusion: The 10-km run time was 4.2% faster following CHO (38 min 08 s ± 2 min 46 s) compared with PLA (39 min 44 s ±3 min 13 s; P < 0.05). The improved run timewas associated with increased GLU and LAC concentrations in the CHO compared with the PLA trial (P < 0.05), no difference in HR or PSU between trials (P > 0.05) and significantly lower RPE scores in the CHO compared with the PLA trial (P < 0.05). These results show that a 10-km run at the end of an Olympic-distance triathlon may be significantly improved following ingestion of a 14.4% glucose-fructose beverage at a rate of 1.8 g min−1 compared with a fruit squash placebo, with no additional gastro-intestinal stress. This improvement in run performance in the CHO trial may be due to muscle and liver glycogen sparing during the cycle leg, which increased carbohydrate metabolism in the latter stages of the triathlon.

  • 38.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Shannon, Oliver
    Univ Bath, Dept Hlth, Human Physiol Res Grp, Bath BA2 7AY, Avon, England.
    Betts, James
    Univ Bath, Dept Hlth, Human Physiol Res Grp, Bath BA2 7AY, Avon, England.
    Ingesting a high-dose carbohydrate solution during the cycle section of a simulated Olympic-distance triathlon improves subsequent run performance2012In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 37, no 4, p. 664-671Article in journal (Refereed)
    Abstract [en]

    The well-established ergogenic benefit of ingesting carbohydrates during single-discipline endurance sports has only been tested once within an Olympic-distance (OD) triathlon. The aim of the present study was to compare the effect of ingesting a 2:1 maltodextrin/fructose solution with a placebo on simulated OD triathlon performance. Six male and 4 female amateur triathletes (age, 25 ± 7 years; body mass, 66.8 ± 9.2 kg; peak oxygen uptake, 4.2 ± 0.6 L·min–1) completed a 1500-m swim time-trial and an incremental cycle test to determine peak oxygen uptake before performing 2 simulated OD triathlons. The swim and cycle sections of the main trials were of fixed intensities, while the run section was completed as a time-trial. Two minutes prior to completing every quarter of the cycle participants consumed 202 ± 20 mL of either a solution containing 1.2 g·min–1 of maltodextrin plus 0.6 g·min–1 of fructose at 14.4% concentration (CHO) or a sugar-free, fruit-flavored drink (PLA). The time-trial was 4.0% ± 1.3% faster during the CHO versus PLA trial, with run times of 38:43 ± 1:10 min:s and 40:22 ± 1:18 min:s, respectively (p = 0.010). Blood glucose concentrations were higher in the CHO versus PLA trial (p < 0.001), while perceived stomach upset did not differ between trials (p = 0.555). The current findings show that a 2:1 maltodextrin/fructose solution (1.8 g·min–1 at 14.4%) ingested throughout the cycle section of a simulated OD triathlon enhances subsequent 10-km run performance in triathletes.

  • 39.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Stocks, Ben
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Betts, James
    The effect of high versus low concentration maltodextrin-fructose ingestion during a simulated 30-km cross-country ski race2014Conference paper (Refereed)
    Abstract [en]

    Introduction

    Long-distance cross-country ski races typically last more than 2 h, depleting muscle glycogen stores in the legs and, to an even greater extent, the arms (Bergström et al. 1973). While carbohydrate (CHO) supplementation demonstrates clear performance-enhancing effects, particularly when ingested during exercise lasting > 1 h and in multiple forms (Jeukendrup 2004), there is limited information regarding the use of CHO during cross-country skiing. Therefore, the aim of the current study was to examine the effect of ingesting two different CHO solutions on 30-km cross-country skiing performance.

    Methods

    10 male and 3 female trained cross-country skiers (age: 30±7 yr; body mass: 74±9 kg; VO2max: 60±6 mL/kg/min) completed 4 x 30-km classic roller-skiing time-trial efforts (consisting of 6 x 5-km loops) on separate days in a randomised, counter-balanced order on a treadmill. Two trials used a high rate of CHO ingestion (2.4 g/min, HC) and two trials used a lower rate of CHO ingestion (1.2 g/min, LC). In addition, two trials used a high frequency of CHO feeds (6 feeds, HF) and two trials used a low frequency of CHO feeds (2 feeds, LF). The CHO was a 1:1 mix of maltodextrin and fructose and the drinks were provided at 24% and 12% concentrations for HC and LC, respectively.

    Results

    There were no significant differences in performance over the four trials (140±16, 139±16, 141±18 and 141±18 min for HC-HF, LC-HF, HC-LF and LC-LF, respectively) and when matched for frequency of feeds, there were no significant performance differences between the paired comparisons (i.e., HC-HF vs LC-HF and HC-LF vs LC-LF). Moreover, there were no significant differences in blood glucose concentrations at 5-km intervals when comparing HC-HF with LC-HF (p>0.05) or HC-LF with LC-LF (p>0.05). However, an order effect was detected for performance (143±17, 140±16, 140±17 and 138±15 min for trials 1-4, respectively) with significant improvements from trials 1-2 (p=0.02) and 3-4 (p=0.03).

    Discussion

    Results from the current study demonstrate no significant differences in 30-km cross-country ski performance when consuming either 2.4 or 1.2 g/min of a mixed CHO solution. Furthermore, there were no significant differences in blood glucose concentrations during exercise between the high and lower CHO trials. However, despite familiarisation to treadmill roller-skiing and the simulated race track, a learning effect was evident. It is concluded that race-track familiarity may have a greater effect on 30-km cross-country ski performance than the rate of CHO ingestion.

  • 40. McGawley, Kerry
    et al.
    Taylor, Daniel
    The effect of short-term sprint-interval training on repeated-sprint ability2010In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 13, no 6, p. e52-Article in journal (Refereed)
    Abstract [en]

    Introduction: The purpose of the present study was to investigate whether short-term sprint-interval training (SIT) would enhance repeated-sprint ability (RSA) via improvements in power output, work decrement and oxygen uptake in recovery. Methods: Eight male, recreational team-sport players (mean±SD age: 21±2 y, body mass: 78.1±4.3 kg) completed a repeated-sprint test (RST) and a graded cycle test to exhaustion for the evaluation of VO2max before and after two weeks of SIT. The RST consisted of 7×5-s cycle sprints interspersed with 25 s of passive recovery. Peak power output (PP), mean power output (MP), decrement in MP (MPdec) and total work done (TWD) were recorded. In addition, VO2 was measured during the 25-s passive recovery periods between each sprint. The SIT involved six sessions (three sessions per week) of 4, 5 or 6 × 30-s, all-out sprints interspersed with 4.5 min of light recovery. The number of sprint repetitions increased by one after every two training sessions. Results and conclusion: Although there was no change in PP for any of the 7×5-s sprints following SIT (P > 0.05) there were significant increases in MP for each of the 7×5-s sprints (P < 0.05) and in TWD during the RST (mean±SD: 7.6±3.0 versus 29.4±2.6 kJ from pre- to post-training; P < 0.05). The MPdec decreased from 12.4 ±6.8 to 7.4±2.9% from pre- to post-training (P < 0.05) but VO2 between sprints was unchanged (P > 0.05). Furthermore, VO2max was not different following training (45.7±7.7 versus 45.0±5.4 mLkg-1 min-1 from pre- to post-training; P > 0.05). These findings suggest that short-term SIT may be an effective intervention for improving RSA within team-sport athletes via increases in work done during each sprint and reductions in the decrement in work done over a series of sprints. This does not appear to be due to greater oxygen uptake during the 25-s recovery periods between sprints or improvements in peak power. Other metabolic adaptations to SIT that maintain muscle force during high-intensity exercise may explain the current findings.

  • 41. McGawley, Kerry
    et al.
    Tyler, Ken
    The effect of water immersion on the recovery of team-sport-specific exercise2010In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 13, no 6, p. e51-Article in journal (Refereed)
    Abstract [en]

    Introduction: The purpose of the present study was to examine the effects of two hydrotherapy techniques, cold water immersion (CWI) and contrast-water therapy (CWT), on the recovery of team-sport-specific exercise tests following muscle-damaging exercise. Methods: Seven male, team-sport players (mean±SD age: 21±2 y, body mass:76.8±7.2 kg) completed a preliminary familiarisation trial for three team-sport-specific exercise tests (TESTS), which included an all-out 30-m sprint test, two agility T-tests (left and right) and a vertical jump test. Three experimental trials were subsequently carried out, each separated by one week, using a counter-balanced cross-over design. On each visit a resting fingertip blood sample and a rating of perceived muscle soreness (PMS) was collected. Participants then performed the TESTS, followed by a 5-min rest period. A repeated sprint exercise (RSE) protocol was then performed to induce muscle damage, which comprised of 15 × 30-m sprints with a 10-m deceleration zone. Sprints were separated by 1 min. A second fingertip blood sample and PMS score was collected immediately after the RSE and a second set of TESTS were performed 10 min after the RSE. Participants then received either CWI, CWT or no water immersion (CON). The next day (24–28 h later) a final fingertip blood sample and PMS score was collected and a final set of TESTS were completed. Results and conclusion: There were no changes in plasma CK over time and no significant interaction effects between the three intervention groups (P > 0.05). The PMS increased from baseline to 24–28 h in the CON group (P < 0.05), but was not different from baseline at 24–28 h for the CWI or CWT groups (P > 0.05). The PMS was significantly higher for CON compared with CWT after 24–28 h (P < 0.05), but no other differences were found between groups (P > 0.05). There were no significant differences in performance during the TESTS between the three intervention groups across any of the three time points (pre RSE, post RSE or after 24–28 h; P > 0.05). These data suggest that the RSE may not have induced sufficient muscle damage to increase plasma CK levels, which may explain why the recovery interventions did not have a significant effect on performance of the TESTS. However, the differences in PMS changes indicate that hydrotherapy may be effective in suppressing the perception of muscle soreness when biochemical and performance markers are unchanged.

  • 42.
    McGawley, Kerry
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Watkins, Jonathan
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Platt, Simon
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Optimal Pacing Strategies And Associated Metabolic Responses During 4-Min Self-Paced Running Time-Trials2016Conference paper (Refereed)
  • 43.
    Nybäck, Linn
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Glännerud, Caroline
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Larsson, Gustav
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Weitzberg, Eddie
    Karolinska Institutet.
    Shannon, Oliver
    Leeds Beckett University, UK.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Physiological and performance effects of nitrate supplementation during roller-skiing in normoxia and normobaric hypoxia2017In: Nitric oxide, ISSN 1089-8603, E-ISSN 1089-8611, Vol. 70, p. 1-8Article in journal (Refereed)
    Abstract [en]

    The present study examined the effects of acute nitrate (NO3-) supplementation ingested in the form of concentrated beetroot juice on cross-country roller-ski performance in normoxia (N) and normobaric hypoxia (H). Eight competitive cross-country skiers (five males: age 22 ± 3 years, V·O2max 71.5 ± 4.7 mL kg-1·min-1; three females: age 21 ± 1 years, V·O2max 58.4 ± 2.5 mL kg-1·min-1) were supplemented with a single dose of NO3--rich beetroot juice (BRJ, ∼13 mmol NO3-) or a NO3--depleted placebo (PL, ∼0 mmol NO3-) and performed 2 x 6-min submaximal exercise bouts and a 1000-m time-trial (TT) on a treadmill in N (20.9% O2) or H (16.8% O2). The four experimental trials were presented in a randomised, counter-balanced order. Plasma NO3- and nitrite concentrations were significantly higher following BRJ compared to PL (both p < 0.001). However, respiratory variables, heart rate, blood lactate concentration, ratings of perceived exertion, and near-infrared spectroscopy-derived measures of muscle tissue oxygenation during submaximal exercise were not significantly different between BRJ and PL (all p > 0.05). Likewise, time to complete the TT was unaffected by supplementation in both N and H (p > 0.05). In conclusion, an acute dose of ∼13 mmol NO3- does not affect physiological or performance responses to submaximal or maximal treadmill roller-skiing in competitive cross-country skiers exercising in N and H.

  • 44.
    Oskarsson, Johanna
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    No individual or combined effects of caffeine and beetroot-juice supplementation during submaximal or maximal running2018In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 43, no 7, p. 697-703Article in journal (Refereed)
    Abstract [en]

    Background: Dietary supplements such as caffeine and beetroot juice are used byathletes in an attempt to optimize performance and therefore gain an advantagein competition. Aim: To investigatethe individual and combined effects of caffeine and beetroot-juicesupplementation during submaximal and maximal treadmill running. Methods: Seven males (VO2max:59.0 ± 2.9 mL/kg/min) and two females (VO2max: 53.1 ± 11.4 mL/kg/min)performed a preliminary trial followed by four experimental test sessions,which consisted of two, 5-min submaximal running bouts (at ~ 70% and 80% of VO2max) and a maximal 1-km time-trial (TT) in a laboratory. Participants ingested a 70-ml dose of concentrated beetroot juice containing either 7.3 mmol of nitrate (BR) or no nitrate (PBR) 2.5 hours prior to each test session, theneither 4.8 ± 0.4 (4.3–5.6) mg/kg caffeine (C) or a caffeine placebo (PC)45 minutes before each test session. The four test sessions (BR-C, BR-PC,PBR-C and PBR-PC) were presented in a counter-balancedand double-blind manner. Results: Nosignificant differences were identified between the four interventionsregarding relative VO2, running economy, RER, heart rate (HR) or RPEat the two submaximal intensities (P > 0.05). Moreover, there were nosignificant differences in performance, maximum HR, peak blood lactateconcentration or RPE during the maximal TT when comparing the interventions (P> 0.05). Conclusion: No beneficialeffects of supplementing with typical doses of caffeine, beetroot juice or acombination of the two were observed for physiological, perceptual orperformance responses during submaximal or maximal treadmill running exercise.

  • 45.
    Oskarsson, Johanna
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The individual and combined effects of beetroot juice and caffeine supplementation during sub-maximal and maximal running2016Conference paper (Refereed)
    Abstract [en]

    Caffeine appears to have a stimulating effect on the central nervous system and as such, is commonly used by athletes to improve performance(1). Nitrate-rich beetroot juice is also used as an ergogenic aid, demonstrating positive effects on both cycling economy and time-trial performance(2). While previous research has shown no additional benefits of combining caffeine and beetroot juice on cycling performance(3), no studies have compared the effects of individual and combined supplementation during running exercise. Therefore, the aim of the current study was to investigate the effects of caffeine and beetroot-juice supplementation during sub-maximal and maximal running.

    Nine recreational runners (seven males, VO2max 59.0 ± 2.9 l/min; two females, VO2max 53.1 ± 11.4 l/min) performed four laboratory-based test sessions in a crossover-design study. Each test session consisted of two, 5-minute sub-maximal running bouts at ~ 70% and 80% of VO2max followed by a maximal 1-km time trial (TT). The participants were given a 70-ml dose of concentrated beetroot juice containing either 4 mmol of nitrate (BJ) or no nitrate (placebo, P) 2.5 hours before warming up for each test. Participants were also given either 4-6 mg/kg body weight of caffeine (C) or a non-caffeine-containing placebo (P) 45 minutes before warming up. The four trials (BJ+C, BJ, C and P) were double-blinded and presented in a randomised order. Data were analysed using one-way ANOVAs with repeated measures.

    There were no significant differences between the four interventions for running economy, respiratory exchange ratio (RER), heart rate (HR) or rating of perceived exertion (RPE) at either of the sub-maximal running intensities (p > 0.05). Neither were there any significant differences in maximal HR or RPE, peak blood lactate concentration or 1-km TT performance between the four interventions (p > 0.05). 

    This study has shown no beneficial effects of combining caffeine and beetroot juice on sub-maximal or maximal running performance compared with BJ, C or P alone.

     

    1. Burke LM (2008) Appl Physiol Nutr Metabol 33, 1319-1334.

    2. Cermak NM, Gibala MJ & van Loon LJC (2012). Int J Sport Nutr Exerc Metab 22, 64-71.

    3. Lane SC, Hawley JA, Desbrow B et al. (2014). Appl Physiol Nutr Metabol 39, 1050-1057.

  • 46.
    Pettersson, Stefan
    et al.
    University of Gothenburg; Swedish Olympic Committee, Stockholm.
    Edin, Fredrik
    University of Gothenburg.
    Bakkman, Linda
    Swedish Olympic Committee, Stockholm.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Effects of supplementing with an 18% carbohydrate-hydrogel drink versus a placebo during whole-body exercise in -5 °C with elite cross-country ski athletes: a crossover study2019In: Journal of the International Society of Sports Nutrition, ISSN 1550-2783, E-ISSN 1550-2783, Vol. 16, no 1, article id 46Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Whilst the ergogenic effects of carbohydrate intake during prolonged exercise are well-documented, few investigations have studied the effects of carbohydrate ingestion during cross-country skiing, a mode of exercise that presents unique metabolic demands on athletes due to the combined use of large upper- and lower-body muscle masses. Moreover, no previous studies have investigated exogenous carbohydrate oxidation rates during cross-country skiing. The current study investigated the effects of a 13C-enriched 18% multiple-transportable carbohydrate solution (1:0.8 maltodextrin:fructose) with additional gelling polysaccharides (CHO-HG) on substrate utilization and gastrointestinal symptoms during prolonged cross-country skiing exercise in the cold, and subsequent double-poling time-trial performance in ~ 20 °C.

    METHODS:

    Twelve elite cross-country ski athletes (6 females, 6 males) performed 120-min of submaximal roller-skiing (69.3 ± 2.9% of [Formula: see text]O2peak) in -5 °C while receiving either 2.2 g CHO-HG·min- 1 or a non-caloric placebo administered in a double-blind, randomized manner. Whole-body substrate utilization and exogenous carbohydrate oxidation was calculated for the last 60 min of the submaximal exercise. The maximal time-trial (2000 m for females, 2400 m for males) immediately followed the 120-min submaximal bout. Repeated-measures ANOVAs with univariate follow-ups were conducted, as well as independent and paired t-tests, and significance was set at P < 0.05. Data are presented as mean ± SD.

    RESULTS:

    Exogenous carbohydrate oxidation contributed 27.6 ± 6.6% to the total energy yield with CHO-HG and the peak exogenous carbohydrate oxidation rate reached 1.33 ± 0.27 g·min- 1. Compared to placebo, fat oxidation decreased by 9.5 ± 4.8% with CHO-HG, total carbohydrate oxidation increased by 9.5 ± 4.8% and endogenous carbohydrate utilization decreased by 18.1 ± 6.4% (all P < 0.05). No severe gastrointestinal symptoms were reported in either trial and euhydration was maintained in both trials. Time-trial performance (8.4 ± 0.4 min) was not improved following CHO-HG compared to placebo (- 0.8 ± 3.5 s; 95% confidence interval - 3.0 to 1.5 s; P = 0.46). No sex differences were identified in substrate utilization or relative performance.

    CONCLUSIONS:

    Ingestion of an 18% multiple-transportable carbohydrate solution with gelling polysaccharides was found to be well-tolerated during 120 min of submaximal whole-body exercise, but did not improve subsequent maximal double-poling performance.

  • 47.
    Shannon, Oliver
    et al.
    Leeds Beckett University Leeds UK.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Nybäck, Linn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Duckworth, Lauren
    Leeds Beckett University Leeds UK.
    Barlow, Matthew J
    Leeds Beckett University Leeds UK.
    Woods, D
    Leeds Beckett University Leeds UK.
    Siervio, M
    University of Newcastle Newcastle upon Tyne UK.
    O'Hara, JP
    Leeds Beckett University Leeds UK.
    "Beet-ing" the mountain: A review of the physiological and performance effects of dietary nitrate supplementation at simulated and terrestrial altitude2017In: Sports Medicine, ISSN 0112-1642, E-ISSN 1179-2035, Vol. 47, no 11, p. 2155-2169Article in journal (Refereed)
    Abstract [en]

    Exposure to altitude results in multiple physiological consequences. These include, but are not limited to, a reduced maximal oxygen consumption, drop in arterial oxygen saturation, and increase in muscle metabolic perturbations at a fixed sub-maximal work rate. Exercise capacity during fixed work rate or incremental exercise and time-trial performance are also impaired at altitude relative to sea level. Recently, dietary nitrate (NO3-) supplementation has attracted considerable interest as a nutritional aid during altitude exposure. In this review, we summarise and critically evaluate the physiological and performance effects of dietary NO3- supplementation during exposure to simulated and terrestrial altitude. Previous investigations at simulated altitude indicate that NO3- supplementation may reduce the oxygen cost of exercise, elevate arterial and tissue oxygen saturation, improve muscle metabolic function, and enhance exercise capacity/performance. Conversely, current evidence suggests that NO3- supplementation does not augment the training response at simulated altitude. Few studies have evaluated the effects of NO3- at terrestrial altitude. Current evidence indicates potential improvements in endothelial function at terrestrial altitude following NO3- supplementation. No effects of NO3- supplementation have been observed on oxygen consumption or arterial oxygen saturation at terrestrial altitude, although further research is warranted. Limitations of the present body of literature are discussed, and directions for future research are provided.

  • 48.
    Sjökvist, Jesper
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Per-Ivar
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Helena
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Physical and performance characteristics of high-level female soccer goalkeepers2012Conference paper (Refereed)
  • 49.
    Spencer, Matthew
    et al.
    Dept of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Olofsson, Anna
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The effect of active, passive and combined warm-up strategies on maximal performance in a very cold environment2018Conference paper (Refereed)
  • 50.
    Stocks, Ben
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Human Physiology Research Group Department for Health University of Bath, Bath, UK.
    Betts, James
    Human Physiology Research Group Department for Health University of Bath, Bath, UK.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Effects of carbohydrate dose and frequency on metabolism, gastrointestinal discomfort, and cross-countryskiing performance2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 9, p. 1100-1108Article in journal (Refereed)
    Abstract [en]

    This study investigated carbohydrate ingestion of varied doses and frequencies during a simulated cross-country skiing time trial. Ten men and three women (age: 30±7years; VO2max: 59.6±5.7 mL/kg/min) completed four, 30-km classic technique roller skiing time trials on a treadmill. A 1:1 maltodextrin-fructose carbohydrate solution was provided at high (2.4 g/min; HC) and moderate (1.2 g/min; MC) ingestion rates, each at high (six feeds;HF) and low (two feeds; LF) frequencies. In the LF trials, blood glucose was elevated following carbohydrate ingestion (at 4 and 19 km) but was reduced at 14 and 29 km compared with HF strategies (P≤0.05). Gastrointestinal discomfort was higher in HC-LF compared with all other trials (P≤0.05). Whole-body lipid oxidation was lowerand carbohydrate oxidation was higher in LF compared with HF trials (P≤0.05). While performance time was not significantly different between trials (140:11±15:31,140:43±17:40, 139:12±15:32 and 140:33±17:46 min:sin HC-HF, HC-LF, MC-HF, and MC-LF, respectively;P>0.05), it was improved with trial order (P<0.001). There was no effect of order on any other variable (P>0.05). Altering carbohydrate dose or frequency does not affect cross-country ski performance. However, low-frequency carbohydrate ingestion resulted in poorer maintenance of euglycemia, reduced lipid oxidation, and increased gastrointestinal discomfort.

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