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  • 1.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    10 metoder för återhämtning2012In: Idrott & kunskap, ISSN 1652-6961, no 4Article in journal (Other (popular science, discussion, etc.))
  • 2.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Electrostimulation's enhancement of recovery during a rugby preseason2013In: International Journal of Sports Physiology and Performance, ISSN 1555-0265, E-ISSN 1555-0273, Vol. 8, no 1, p. 92-98Article in journal (Refereed)
  • 3.
    Beaven, C. Martyn
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Ekstrom, Johan
    Mid Sweden University, Faculty of Human Sciences, Department of Psychology.
    A Comparison of Blue Light and Caffeine Effects on Cognitive Function and Alertness in Humans2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 10, p. e76707-Article in journal (Refereed)
    Abstract [en]

    The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of similar to 40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.

  • 4.
    Beaven, C. Martyn
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. United Kingdom Sports Council, London, WC1N 1ST, United Kingdom .
    Maulder, Peter
    School of Sport and Exercise Science, Waikato Institute of Technology, Hamilton, 3200, New Zealand .
    Pooley, Adrian
    School of Sport and Exercise Science, Waikato Institute of Technology, Hamilton, 3200, New Zealand .
    Kilduff, Liam
    Health and Sport Portfolio, College of Engineering, Swansea University, Swansea, SA2 8PP Wales, United Kingdom .
    Cook, Christian
    United Kingdom Sports Council, London, WC1N 1ST, United Kingdom .
    Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance2013In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 38, no 6, p. 633-637Article in journal (Refereed)
    Abstract [en]

    Introduction: Our purpose was to examine the effectiveness of carbohydrate and caffeine mouth rinses on enhancing repeated sprint ability. Previously, beneficial effects of a carbohydrate mouth rinse (without ingestion) on endurance performance have been related to changes in brain activity. Caffeine ingestion has also demonstrated positive effects on sprint performance. However, the effects of carbohydrate or caffeine mouth rinses on intermittent sprints have not previously been examined. Methods: Twelve males performed 5 x 6 s sprints interspersed by 24 s of active recovery on a cycle ergometer. Twenty-five ml of either a non-caloric placebo, 6% glucose, or 1.2% caffeine solution was rinsed in the mouth for 5 s prior to each sprint in a double-blinded and balanced, cross-over design. Post-exercise maximal heart rate and perceived exertion were recorded along with power measures. A second experiment compared a combined caffeine-carbohydrate rinse with carbohydrate-only. Results: Compared to the placebo mouth rinse, carbohydrate substantially increased Sprint 1 peak power (22.1 ±19.5 W; ES: 0.81), and both caffeine (26.9 ±26.9 W; ES: 0.71) and carbohydrate (39.1 ±25.8 W; ES: 1.08) improved mean power in Sprint 1. Experiment 2 demonstrated that a combination of caffeine and carbohydrate improved Sprint 1 power production compared to carbohydrate alone (36.0 ±37.3 W; ES: 0.81). Conclusions: Carbohydrate and/or caffeine mouth rinses may rapidly enhance power production which could have benefits for specific short sprint exercise performance. The ability of a mouth rinse intervention to rapidly improve maximal exercise performance in the absence of fatigue suggests a central mechanism.

  • 5. Beaven, Christopher
    Acute salivary hormone responses to complex exercise bouts2010In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 25, no 4, p. 1072-1078Article in journal (Refereed)
    Abstract [en]

    The combination of resistance and plyometric training, or complex training, may yield greater functional gains than either method alone.As steroid hormones respond to exercise stimuli and modulate the functional outcomes, it is possible that complex training creates an enhanced anabolic physiological milieu for adaptation.

    We investigated acute responses of salivary testosterone and cortisol to complex exercise bouts.

    After a standardized warm-up, 16 semiprofessional rugby players performed 1 of 4 exercise bouts in a cross-over manner: power-power; power-strength; strength-power; or strength-strength.Each player completed each of the 4 bouts twice over a 4-week period in a balanced random order such that each player performed a total of 8 bouts.The power block consisted of 3 sets of 3 repetitions of jump squat exercise at 50% of 1-repetition maximum load.The strength block consisted of three sets of three repetitions of box squat exercise at a 3-repetition maximum load.There were 3-minute rest periods between sets and 4-minute rest periods between exercise blocks.Saliva was sampled before, during, and immediately after the exercise bout.

    The greatest overall hormonal responses were a small increase in testosterone (13%; 90% confidence limits +/-7%) and a trivial increase in cortisol (27%; +/-30%) after the strength-power bout.A clear difference was observed between the strength-power and the power-power bouts immediately after exercise for testosterone (10%; +/-8%) and cortisol (29%; +/-17%).The preceding exercise block had little effect on subsequent strength and power performance.

    The hormonal response after the strength-power bout suggests that this exercise sequence provides an enhanced anabolic milieu for adaptation.

  • 6. Beaven, Christopher
    Changes in strength, power, and steroid hormones during a professional rugby union competition2009In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 23, no 5, p. 1583-1592Article in journal (Refereed)
    Abstract [en]

    The purpose of this investigation was to assess changes in strength, power, and levels of testosterone and cortisol over a 13-week elite competitive rugby union season. Thirty-two professional rugby union athletes from a Super 14 rugby team (age, 24.4 6 2.7 years; height, 184.7 6 6.2 cm; mass, 104.0 6 11.2 kg; mean 6 SD) were assessed for upper-body and lower-body strength (bench press and box squat, respectively) and power (bench throw and jump squat, respectively) up to 5 times throughout the competitive season. Salivary testosterone and cortisol samples, along with ratings of perceived soreness and tiredness, were also obtained before each power assessment.An effect size of 0.2 was interpreted as the smallest worthwhile change.

    A small increase in lower body strength was observed over the study period (8.5%; 90% confidence limits 67.2%), whereas upper-body strength was maintained (21.2%; 62.7%). Decreases in lower-body power (23.3%; 65.5%) and upper-body power (23.4; 64.9%) were small and trivial.There were moderate increases in testosterone (54%; 627%) and cortisol (97%; 651%) over the competitive season, and the testosterone to cortisol ratio showed a small decline (22%; 625%), whereas changes in perceived soreness and tiredness were trivial. Individual differences over the competitive season for all measures were mostly trivial or inestimable.

    Some small to moderate relationships were observed between strength and power; however, relationships between hormonal concentrations and performance were mainly trivial but unclear.

    Positive adaptation in strength and power may be primarily affected by cumulative training volume and stimulus over a competitive season. Greater than 2 resistance sessions per week may be needed to improve strength and power in elite rugby union athletes during a competitive season.

  • 7. Beaven, Christopher
    Development and validation of a sensitive immunoassay for the skeletal muscle isoform of creatine kinase2008In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 369Article in journal (Refereed)
    Abstract [en]

    Creatine kinase (CK) is a marker of muscle damage and pathology present as multiple tissue-specific circulating isoforms. CK is often measured using enzyme activity assays that are unable to distinguish these isoforms. We have developed an immunoassay specific for the MM isoform of CK, found predominantly in skeletal muscle, which uses very small volumes of plasma (1–2μL). A sandwich enzyme-linked immunosorbent assay (ELISA) for CK-MM was developed using isoform-specific antibodies. Cross-reactivity with CK-BB and MB isoforms was also assessed. The ELISA was validated using plasma samples from a group of athletes, and the measured CK-MM concentrations were correlated with CK enzyme activity assays measured by a contractor using the same samples.

    The CK-MM ELISA has a limit of detection of 0.02ng/mL, an IC50 of 2.3ng/mL, and 5.8% cross-reactivity with CK-MB. CK-MM concentrations measured using this assay correlate well (p<0.0001, Spearman r=0.89) with enzyme activity assays.

    The CK-MM-specific ELISA can be used to help assess skeletal muscle damage independent of enzyme activity or interference from other CK isoforms, leading to more precise studies of muscle biology.

  • 8. Beaven, Christopher
    Dose effect of caffeine on testosterone and cortisol responses to resistance exercise2008In: International Journal of Sport Nutrition & Exercise Metabolism, ISSN 1526-484X, E-ISSN 1543-2742, Vol. 18, no 2, p. 131-141Article in journal (Refereed)
    Abstract [en]

    Introduction: Interest in the use of caffeine as an ergogenic aid has increased since the International Olympic Committee lifted the partial ban on its use. Caffeine has beneficial effects on various aspects of athletic performance, but its effects on training have been neglected.

    Purpose: To investigate the acute effect of caffeine on the exercise-associated increases in testosterone and cortisol in a double-blind crossover study.

    Methods: 24 professional rugby-league players ingested caffeine doses of 0, 200, 400 and 800 mg in random order 1 h before a resistance-exercise session. Saliva was sampled at the time of caffeine ingestion, at 15-min intervals throughout each session, and at 15 and 30 min after the session. Data were log transformed to estimate percent effects with mixed modeling, and effects were standardized to assess magnitudes.

    Results: Testosterone concentration showed a small increase of 15% (90% confidence limits, ±19%) during exercise. Caffeine raised this concentration in a dose-dependent manner by a further small 21% (±24%) at the highest dose. The 800-mg dose also produced a moderate 52% (±44%) increase in cortisol. The effect of caffeine on the testosterone/cortisol ratio was a small decline (14; ±21%).

    Conclusion: Caffeine has some potential to benefit training outcomes via the anabolic effects of the increase in testosterone concentration, but this benefit may be counteracted by the opposing catabolic effects of the increase in cortisol and resultant decline in the testosterone/cortisol ratio.

  • 9. Beaven, Christopher
    Effectiveness of post-match recovery strategies in rugby players2006In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 40, p. 260-263-Article in journal (Refereed)
    Abstract [en]

    Objectives: To examine the effectiveness of four interventions on the rate and magnitude of muscle damage recovery, as measured by creatine kinase (CK).

    Methods: 23 elite male rugby players were monitored transdermally before, immediately after, 36 hours after, and 84 hours after competitive rugby matches. Players were randomly assigned to complete one of four post-match strategies: contrast water therapy (CWT), compression garment (GAR), low intensity active exercise (ACT), and passive recovery (PAS).

    Results: Significant increases in CK activity in transdermal exudate were observed as a result of the rugby match (p<0.01). The magnitude of recovery in the PAS intervention was significantly worse than in the ACT, CWT, and GAR interventions at the 36 and 84 hour time points (p<0.05).

    Conclusions: An enhanced rate and magnitude of recovery was observed in the ACT, CWT, and GAR treatment groups when compared with the PAS group. Low impact exercise immediately post-competition, wearing compression garments, or carrying out contrast water therapy enhanced CK clearance more than passive recovery in young male athletes.

  • 10. Beaven, Christopher
    Effects of a short-term pre-season training programme on the body composition and anaerobic performance of professional rugby union players2010In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 28, no 6, p. 679-686Article in journal (Refereed)
    Abstract [en]

    Pre-season rugby training develops the physical requisites for competition and consists of a high volume of resistance training and anaerobic and aerobic conditioning.However, the effects of a rugby union pre-season in professional athletes are currently unknown.Therefore, the purpose of this investigation was to determine the effects of a 4-week pre-season on 33 professional rugby union players.

    Bench press and box squat increased moderately (13.6 kg, 90% confidence limits+2.9 kg and 17.6+8.0 kg, respectively) over the training phase.Small decreases in bench throw (70.6+53.5 W), jump squat (280.1+232.4 W), and fat mass (1.4+0.4 kg) were observed.In addition, small increases were seen in fat-free mass (2.0+0.6 kg) and flexed upper-arm girth (0.6+0.2 cm), while moderate increases were observed in mid-thigh girth (1.9+0.5 cm) and perception of fatigue (0.6+0.4 units).

    Increases in strength and body composition were observed in elite rugby union players after 4 weeks of intensive pre-season training, but this may have been the result of a return to fitness levels prior to the off-season.Decreases in power may reflect high training volumes and increases in perceived of fatigue.

  • 11.
    Beaven, Christopher
    Auckland University of Technology.
    Hormone-mediated Strategies to Enhance Training and Performance2010Doctoral thesis, monograph (Other academic)
  • 12. Beaven, Christopher
    Kinetic, kinematic and training comparisons between assisted, resisted and bodyweight countermovement jumps2009Conference paper (Refereed)
  • 13. Beaven, Christopher
    Physiology of Risk2007In: Berkshire Encyclopedia of Extreme Sports, Berkeley Electronic Press, 2007Chapter in book (Refereed)
  • 14. Beaven, Christopher
    Salivary testosterone and cortisol responses following four resistance training protocols in professional rugby players2008In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 22, no 2, p. 426-432Article in journal (Refereed)
    Abstract [en]

    The acute response of free salivary testosterone (T) and cortisol (C) concentrations to four resistance exercise (RE) protocols in 23 elite men rugby players was investigated.

    We hypothesized that hormonal responses would differ among individuals after four distinct RE protocols: four sets of 10 repetitions (reps) at 70% of 1 repetition maximum (1RM) with 2 minutes' rest between sets (4 × 10-70%); three sets of five reps at 85% 1RM with 3 minutes' rest (3 × 5-85%); five sets of 15 reps at 55% 1RM with 1 minute's rest (5 × 15-55%); and three sets of five reps at 40% 1RM with 3 minutes' rest (3 × 5-40%).

    Each athlete completed each of the four RE protocols in a random order on separate days. T and C concentrations were measured before exercise (PRE), immediately after exercise (POST), and 30 minutes post exercise (30 POST). Each protocol consisted of four exercises: bench press, leg press, seated row, and squats.

    Pooled T data did not change as a result of RE, whereas C declined significantly.

    Individual athletes differed in their T response to each of the protocols, a difference that was masked when examining the pooled group data. When individual data were retrospectively tabulated according to the protocol in which each athlete showed the highest T response, a significant protocol-dependent T increase for all individuals was revealed.Therefore, RE induced significant individual, protocol-dependent hormonal changes lasting up to 30 minutes after exercise.

    These individual responses may have important ramifications for modulating adaptation to RE and could explain the variability often observed in studies of hormonal response to RE.

  • 15. Beaven, Christopher
    Significant strength gains observed in rugby players following specific RE protocols based on individual salivary testosterone responses.2008In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 22, no 2, p. 419-425-Article in journal (Refereed)
    Abstract [en]

    Our previous work has demonstrated that professional athletes show protocol-dependent variability in salivary testosterone (T) responses to resistance exercise (RE). The current study examines the consistency and functional outcomes of prescribing a RE regimen based on T response. We hypothesized that prescribing an individual-specific RE protocol based on T response would enhance weight training gains.Sixteen amateur rugby players [(mean ± SD) age: 20 ± 2 years; height: 181.5 ± 8.2 cm; weight: 94.2 ± 11.1 kg] were characterized by their maximal (Tmax) and minimal (Tmin) T response to four RE protocols: four sets of 10 repetitions (reps) at 70% of one repetition maximum (1 RM) with 2 minutes' rest between sets (4 x 10-709/o); three sets of five reps at 85% 1 RM with 3 minutes' rest (3 x 5-85%); five sets of 15 reps at 55% of 1 RM with 1 minute's rest (5 x 15-559/o); and three sets of 5 reps at 40% 1 RM with 3 minutes' rest (3 X 5-40%).Eight athletes then performed a 3-week training block performing only their Tmax protocol. The remaining eight only performed Tmin. After 3 weeks, the athletes were retested on the RE protocols and then crossed over and performed the alternate 3-week training block.

    All 16 athletes showed significant increases in estimated bench and leg press 1 RM strength and bodyweight while performing Tmax. When Tmin was performed, 75% of athletes showed either no change or a significant decline in 1 RM performance.

    Consistent protocol-responses over the experimental period were seen for both the Tmax and Tmin protocols in 12 of 16 athletes. Thus, a relationship between an individual's biologically available T response to RE and enhanced functional gains is reported.

  • 16. Beaven, Christopher
    The relationship between changes in interstitial creatine kinase and game-related impacts in rugby union2008In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 42, no 3, p. 198-201Article in journal (Refereed)
    Abstract [en]

    Aim: The primary purpose of this study was to investigate the relationship between the pre-game to post-game changes in creatine kinase concentration ([CK]) and impact-related game statistics in elite rugby union players.

    Methods: Twenty-three elite male rugby union players each provided interstitial fluid samples obtained via electrosonophoresis (ESoP) 210 min before and within a maximum time of 30 min after up to five rugby union games. Specific game statistics that were deemed to be important in determining the relationship between impact and [CK] were obtained from AnalyRugby software for each individual player. Regression equations to predict [CK] from game statistics were created using a backwards random-effects maximum likelihood regression.

    Results: The [CK] (mean (SD)) from pre-game to post-game was 926.8 (204.2) IU. Game time and time defending were significantly correlated to [CK] in both the forwards and backs. The predicted [CK] (mean (95% confidence limit)) was 1439.8 (204.9) IU for the forwards and 545.3 (78.0) IU for the backs and was significantly correlated with the actual [CK] (r = 0.69 and r = 0.74).

    Conclusions: CK increased from pre-game to post-game in a position-specific manner. A large proportion of the [CK] can be explained by physical impact and thus can be predicted using a prescribed number of game statistics. As the [CK] is an indicator of muscle damage, the prediction of [CK] provides a theoretical basis for recovery strategies and adjustment of subsequent training sessions after rugby union games.

  • 17. Beaven, Christopher
    Ultradian rhythmicity and induced changes in salivary testosterone2010In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 10, no 2, p. 405-413Article in journal (Refereed)
    Abstract [en]

    Testosterone and cortisol respond to exercise stimuli and modulate adaptation.Episodic basal secretion of these hormones may modify the responsiveness of these hormones.We sought to identify episodic steroid secretion via frequent salivary sampling and investigate any interaction between ultradian rhythmicity and induced changes in testosterone.

    Salivary testosterone and cortisol concentrations of seven males (age 20-40 y) were measured every 10 min between 0800-1600 h on three consecutive days.On either the second or third day, three interventions designed to elicit a hormonal response were randomly assigned: sprint exercise (two 30-s maximal efforts on a cycle ergometer); boxing (two 30-s maximal punching efforts); and a violent video game (10 min of player-versus-player combat).On the other days subjects were inactive.

    Testosterone data on non-intervention days suggested pulsatile secretion with a pulse interval of 47 ± 9 min (mean ± SD).The sprint intervention substantially affected hormones: it elicited a small transient elevation in testosterone (by a factor of 1.21; factor 90% confidence limits x/1.21) 10 min after exercise, and a moderate elevation in cortisol peaking 50 min post-exercise (factor 2.3; x/2.6).The testosterone response correlated with the change in testosterone concentration in the 10 min prior to the sprint (r=0.78; 90%CL 0.22 to 0.95) and with a measure of randomness in testosterone fluctuations (r=0.83; 0.35 to 0.96).

    Thus, the salivary testosterone response to exercise may be dependent on the underlying ultradian rhythm and aspects of its regulation.This interaction may have important implications for adaptation to exercise.

  • 18.
    Beaven, Christopher Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Intermittent lower-limb occlusion enhances recovery after strenuous exercise2012In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 37, no 6, p. 1132-1139Article in journal (Refereed)
    Abstract [en]

    Repeated cycles of vascular occlusion followed by reperfusion initiate a protective mechanism that acts to mitigate future cell injury. Such ischemic episodes are known to improve vasodilation, oxygen utilization, muscle function, and have been demonstrated to enhance exercise performance. Thus, the use of occlusion cuffs represents a novel intervention that may improve subsequent exercise performance. Fourteen participants performed an exercise protocol that involved lower-body strength and power tests followed by repeated sprints. Occlusion cuffs were then applied unilaterally (2 x 3-min per leg) with a pressure of either 220 (intervention) or 15 mm Hg (control). Participants immediately repeated the exercise protocol, and then again 24 h later. The intervention elicited delayed beneficial effects (24 h post-intervention) in the countermovement jump test with concentric (effect size (ES) = 0.36) and eccentric (ES = 0.26) velocity recovering more rapidly compared with the c!

     ontrol. There were also small beneficial effects on 10- and 40-m sprint times. In the squat jump test there were delayed beneficial effects of occlusion on eccentric power (ES = 1.38), acceleration (ES = 1.24), and an immediate positive effect on jump height (ES = 0.61). Thus, specific beneficial effects on recovery of power production and sprint performance were observed both immediately and 24 h after intermittent unilateral occlusion was applied to each leg.

  • 19.
    Beaven, Martyn
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Willis, Sarah
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Cook, Christian
    School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Physiological comparison of concentric and eccentric arm cycling in males and females2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 9, p. Art. no. e112079-Article in journal (Refereed)
    Abstract [en]

    Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC) or concentric (CON) arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial. The heart rate, ventilation, cardiac output, respiratory exchange ratio, and blood lactate concentrations were all clearly greater in CON condition at all of the relative workloads (all p<0.003). Effect size calculations demonstrated that the magnitude of the differences in VO2 and work economy between the ECC and CON exercise ranged from very large to extremely large; however, in no case did mechanical efficiency (ηMECH) differ between the conditions (all p>0.05). In contrast, delta efficiency (ηΔ), as previously defined by Coyle and colleagues in 1992, demonstrated a sex difference (men>women; p<0.05). Sex differences were also apparent in arteriovenous oxygen difference and heart rate during CON. Here, we reinforce the high-force, low cost attributes of eccentric exercise which can be generalised to the muscles of the upper body. Upper body eccentric exercise is likely to form a useful adjunct in debilitative, rehabilitative, and adaptive clinical exercise programs; however, reports of a shift towards an oxidative phenotype should be taken into consideration by power athletes. We suggest delta efficiency as a sensitive measure of efficiency that allowed the identification of sex differences.

  • 20.
    Cook, C
    et al.
    United Kingdom Sports Council, London, England .
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Kilduff, L P
    Swansea Univ, Coll Engn, Swansea, W Glam, Wales.
    Drawer, S
    United Kingdom Sports Council, London, England .
    Acute caffeine ingestion increases voluntarily chosen resistance training load following limited sleep2012In: International Journal of Sport Nutrition & Exercise Metabolism, ISSN 1526-484X, E-ISSN 1543-2742, Vol. 22, no 3, p. 157-164Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION:This study aimed to determine whether caffeine ingestion would increase the workload voluntarily chosen by athletes in a limited sleep state.

    METHODS:In a double-blind, crossover study, sixteen professional rugby players ingested either a placebo or 4 mg·kg-1 caffeine 1 h before exercise. Athletes classified themselves into non-deprived (8 h+) or sleep-deprived states (6 h or less). Exercise comprised four sets of bench press, squats, and bent rows at 85% 1-RM. Athletes were asked to perform as many repetitions on each set as possible without failure. Saliva was collected prior to administration of placebo or caffeine, and again prior to and immediately after exercise and assayed for testosterone and cortisol.

    RESULTS:Sleep deprivation produced a very large decrease in total load (p = 1.98 x 10-7).Caffeine ingestion in the non-deprived state resulted in a moderate increase in total load with a larger effect in the sleep deprived state resulting in total load similar to those observed in the non-deprived placebo condition.Eight of the sixteen athletes were identified as caffeine responders.Baseline testosterone was higher (p < 0.05) and cortisol trended lower in non-sleep deprived states.Changes in hormones from pre-dose to pre-exercise correlated to individual workload responses to caffeine.Testosterone response to exercise increased with caffeine compared to placebo, as did cortisol response.

    CONCLUSIONS:Caffeine increased voluntary workload in professional athletes, emphasised further under conditions of self-reported limited sleep. Caffeine may prove worthwhile when athletes are perceived as tired, especially in individuals identified as responders.

  • 21.
    Cook, C. J.
    et al.
    Hamlyn Centre, Institute of Global Health Innovation, Imperial College, London, United Kingdom.
    Beaven, Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Salivary testosterone is related to self-selected training load in elite female athletes2013In: Physiology and Behavior, ISSN 0031-9384, E-ISSN 1873-507X, Vol. 116-117, p. 8-12Article in journal (Refereed)
    Abstract [en]

    Background: Testosterone has been related to improved acute neuromuscular performance in athletic populations. It is our contention that testosterone may also contribute to improved volitional motivation and, when monitored longitudinally, may provide one proxy marker for readiness to perform. Methods: Twelve female netball players provided saliva samples prior to five standardized training sessions in which they completed a maximal-distance medicine ball throw, and then 3 sets of bench press and then back squat using a self-selected load perceived to equal a 3-repetition maximum load. Additional repetitions were encouraged when possible and total voluntary workload was calculated from the product of the load lifted and repetitions performed. Results: Relative salivary testosterone levels as a group were correlated with bench press (r = 0.8399; p = 0.0007) and squat (r = 0.6703; p = 0.0171) self-selected workload, as well as maximal medicine ball throw performance (r = 0.7062; p = 0.0103). Conclusions: Individual salivary testosterone, when viewed relatively over time, demonstrated strong relationships with self-selected workloads during an in-season training period in female netball players. As such, daily variations in testosterone may provide information regarding voluntary training motivation and readiness to perform in elite athletic populations. Psychological and behavioral aspects of testosterone may have the potential to enhance training adaptation by complementing the known anabolic and permissive properties of testosterone.

  • 22.
    Cook, C. J.
    et al.
    United Kingdom Sports Council, London, United Kingdom .
    Kilduff, L. P.
    Exercise and Medicine Research Centre, Swansea University, Swansea, United Kingdom .
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Improving strength and power in trained athletes with 3 weeks of occlusion training2014In: International Journal of Sports Physiology and Performance, ISSN 1555-0265, E-ISSN 1555-0273, Vol. 9, no 1, p. 166-172Article in journal (Refereed)
    Abstract [en]

    Purpose: To examine the effects of moderate-load exercise with and without blood-flow restriction (BFR) on strength, power, and repeated-sprint ability, along with acute and chronic salivary hormonal parameters. Methods: Twenty male semiprofessional rugby union athletes were randomized to a lower-body BFR intervention (an occlusion cuff inflated to 180 mmHg worn intermittently on the proximal thighs) or a control intervention that trained without occlusion in a crossover design. Experimental sessions were performed 3 times a week for 3 wk with 5 sets of 5 repetitions of bench press, leg squat, and pull-ups performed at 70% of 1-repetition maximum. Results: Greater improvements were observed (occlusion training vs control) in bench press (5.4 ± 2.6 vs 3.3 ± 1.4 kg), squat (7.8 ± 2.1 vs 4.3 ± 1.4 kg), maximum sprint time (-0.03 ± 0.03 vs -0.01 ± 0.02 s), and leg power (168 ± 105 vs 68 ± 50 W). Greater exercise-induced salivary testosterone (ES 0.84-0.61) and cortisol responses (ES 0.65-0.20) were observed after the occlusion intervention sessions compared with the nonoccluded controls; however, the acute cortisol increases were attenuated across the training block. Conclusions: Occlusion training can potentially improve the rate of strength-training gains and fatigue resistance in trained athletes, possibly allowing greater gains from lower loading that could be of benefit during high training loads, in competitive seasons, or in a rehabilitative setting. The clear improvement in bench-press strength resulting from lower-body occlusion suggests a systemic effect of BFR training. © 2014 Human Kinetics, Inc.

  • 23.
    Cook, C. J.
    et al.
    UK Sport, London, United Kingdom.
    Kilduff, L. P.
    Applied Sports Technology Exercise and Medicine Research Centre (A-STEM), Health and Sport Portfolio, College of Engineering, Swansea University, Swansea, United Kingdom .
    Crewther, B. T.
    Hamlyn Centre, Imperial College, London, United Kingdom .
    Beaven, Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    West, D. J.
    Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Science, Northumbria University, Northumberland Building, Newcastle upon Tyne, United Kingdom .
    Morning based strength training improves afternoon physical performance in rugby union players2014In: Journal of Science and Medicine in Sport, ISSN 1878-1861, Vol. 17, no 3, p. 317-321Article in journal (Refereed)
    Abstract [en]

    ObjectivesTo determine if a morning training session could alter afternoon physical performance. Moreover, as testosterone (T) and cortisol (C) concentrations are significant predictors of physical performance, and both show circadian declines across the day, we examined the effects of morning training on diurnal T and C responses. DesignEighteen semi-professional rugby union players completed this randomised and counter-balanced study. MethodsFollowing morning saliva collection (0900. h), players completed a control (rested), Sprint (5 × 40 m) or Weights (3 repetition-maximum [RM] bench press and squat) trial. In the afternoon (15:00. h) of each trial, a further saliva sample was collected before players completed a performance test (3RM back squat and bench press, 40. m sprint, countermovement jump [CMJ]). ResultsSalivary T concentrations declined from am to pm under Control and Sprint, but not under Weights. Delta T, from am to pm, was greater under Control (-10.9±2.4pgml-1) compared to Sprints (-6.2±7.1pgml-1) and Weights (-1.2±5.5pgml-1) (p≤0.001). Delta C, from am to pm, was greater under Control compared to both Sprint and Weights (p&lt;0.05). Players elicited better CMJ peak power, 40-m time, 3RM bench and squat performance under Weights compared with Control and Sprint (p&lt;0.05). Faster 40-m times were seen under Sprint, when compared to Control (p&lt;0.05). ConclusionsPerforming morning strength training is associated with improved physical performance in the afternoon. Additionally, the circadian decline in T concentrations appeared offset by morning training. However, it is unclear if T concentrations are, in part, causal of these improved responses or simply a reflective marker. © 2013 Sports Medicine Australia.

  • 24.
    Cook, Christian J.
    et al.
    Univ London Imperial Coll Sci Technol & Med, Inst Global Hlth Innovat, Hamlyn Ctr, London, England.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Swedish Olymp Comm, Stockholm, Sweden.
    Individual perception of recovery is related to subsequent sprint performance2013In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 47, no 11, p. 705-709Article in journal (Refereed)
    Abstract [en]

    Background Training recovery is vital for adaptation and performance, and to avoid cumulative fatigue and symptoms associated with overtraining. The use of cold-water immersion (CWI) as a recovery strategy is common; however, the physiological and biochemical rationale behind its use remains unclear. This study aimed to assess the relationship between body temperature responses to water immersion and individual perception of recovery, with subsequent exercise performance. Methods Twelve male rugby players participated in a 3-week cross-over trial where an intense 60 min conditioning session was followed immediately by 15 min of either 14 degrees C CWI, 30 degrees C warm-water immersion (WWI) or passive control (CON) recovery intervention. Postexercise body temperatures and subjective ratings of the recovery intervention were recorded and subsequently related to performance in a 5x40 m repeated sprint protocol undertaken 24 h later. Results CWI induced large reductions in core body temperature postimmersion (effect size (ES) range 1.05-3.21) and improved subsequent sprint performance compared to WWI (ES 1.04 +/- 0.84) and CON (ES 1.44 +/- 0.84). Both the degree of temperature decrease at 60 min postimmersion (r=0.6948; p=0.0121) and the subjective rating of the recovery intervention (r=0.5886; p=0.0441) were related to subsequent sprint performance. A very strong linear correlation was observed when these two factors were integrated (r=0.7743; p=0.0031). Conclusion A combination of physiological and psychological indices provides an improved indication of subsequent performance and suggests an important role of individual perception in enhancing training recovery.

  • 25.
    Cook, Christian J.
    et al.
    United Kingdom Sports Council, London, United Kingdom.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. United Kingdom Sports Council, London, United Kingdom.
    Kilduff, Liam P.
    Department of Sports Science, Health and Sport Portfolio, College of Engineering, Swansea University, Swansea, United Kingdom.
    THREE WEEKS OF ECCENTRIC TRAINING COMBINED WITH OVERSPEED EXERCISES ENHANCES POWER AND RUNNING SPEED PERFORMANCE GAINS IN TRAINED ATHLETES2013In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 27, no 5, p. 1280-1286Article in journal (Refereed)
    Abstract [en]

    Eccentric and overspeed training modalities are effective in improving components of muscular power. Eccentric training induces specific training adaptations relating to muscular force, whereas overspeed stimuli target the velocity component of power expression. We aimed to compare the effects of traditional or eccentric training with volume-matched training that incorporated overspeed exercises. Twenty team-sport athletes performed 4 counterbalanced 3-week training blocks consecutively as part of a preseason training period: (1) traditional resistance training; (2) eccentric-only resistance training; (3) traditional resistance training with overspeed exercises; and (4) eccentric resistance training with overspeed exercises. The overspeed exercises performed were assisted countermovement jumps and downhill running. Improvements in bench press (15.0 +/- 5.1 kg; effect size [ES]: 1.52), squat (19.5 +/- 9.1 kg; ES: 1.12), and peak power in the countermovement jump (447 +/- 248 W; ES: 0.94) were observed following the 12-week training period. Greater strength increases were observed as a result of the eccentric training modalities (ES: 0.72-1.09) with no effect of the overspeed stimuli on these measures (p > 0.05). Eccentric training with overspeed stimuli was more effective than traditional resistance training in increasing peak power in the countermovement jump (94 +/- 55 W; ES: 0.95). Eccentric training induced no beneficial training response in maximal running speed (p > 0.05); how-ever, the addition of overspeed exercises salvaged this relatively negative effect when compared with eccentric training alone (0.03 +/- 0.01 seconds; ES: 1.33). These training results achieved in 3-week training blocks suggest that it is important to target-specific aspects of both force and movement velocity to enhance functional measures of power expression.

  • 26.
    Ekström, Johan G.
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Effects of blue light and caffeine on mood2014In: Psychopharmacology, ISSN 0033-3158, E-ISSN 1432-2072, Vol. 231, no 18, p. 3677-3683Article in journal (Refereed)
    Abstract [en]

    Both short wavelength (blue) light and caffeine have been studied for their mood enhancing effects on humans. The ability of blue light to increase alertness, mood and cognitive function via non-image forming neuropathways has been suggested as a non-pharmacological countermeasure for depression across a range of occupational settings. This experimental study compared blue light and caffeine and aimed to test the effects of blue light/placebo (BLU), white light/240-mg caffeine (CAF), blue light/240-mg caffeine (BCAF) and white light/placebo (PLA), on mood. A randomised, controlled, crossover design study was used, in a convenience population of 20 healthy volunteers. The participants rated their mood on the Swedish Core Affect Scales (SCAS) prior to and after each experimental condition to assess the dimensions of valence and activation. There was a significant main effect of light (p = 0.009), and the combination of blue light and caffeine had clear positive effects on core effects (ES, ranging from 0.41 to 1.20) and global mood (ES, 0.61 +/- 0.53). The benefits of the combination of blue light and caffeine should be further investigated across a range of applications due to the observed effects on the dimensions of arousal, valence and pleasant activation.

  • 27.
    Hebert-Losier, Kim
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    THE MARS FOR SQUAT, COUNTERMOVEMENT, AND STANDING LONG JUMP PERFORMANCE ANALYSES: ARE MEASURES REPRODUCIBLE?2014In: JOURNAL OF STRENGTH AND CONDITIONING RESEARCH, ISSN 1533-4287, Vol. 28, no 7, p. 1849-1857Article in journal (Refereed)
    Abstract [en]

    The MARS for squat, countermovement, and standing long jump performance analyses: are measures reproducible? J Strength Cond Res 28(7): 18491857, 2014-Jump tests are often used to assess the effect of interventions because their outcomes are reported valid indicators of functional performance. In this study, we examined the reproducibility of performance parameters from 3 common jump tests obtained using the commercially available Kistler Measurement, Analysis and Reporting Software (MARS). On 2 separate days, 32 men performed 3 squat jumps (SJs), 3 countermovement jumps (CMJs), and 3 standing long jumps (LJs) on a Kistler force-plate. On both days, the performance measures from the best jump of each series were extracted using the MARS. Changes in the mean scores, intraclass correlation coefficients (ICCs), and coefficients of variations (CVs) were computed to quantify the between-day reproducibility of each parameter. Moreover, the reproducibility quantifiers specific to the 3 separate jumps were compared using nonparametric tests. Overall, an acceptable between-day reproducibility (mean +/- SD, ICC, and CV) of SJ (0.88 +/- 0.06 and 7.1 +/- 3.8%), CMJ (0.84 +/- 0.17 and 5.9 +/- 4.1%), and LJ (0.80 +/- 0.13 and 8.1 +/- 4.1%) measures was found using the MARS, except for parameters directly relating to the rate of force development (i.e., time to maximal force) and change in momentum during countermovement (i.e., negative force impulse) where reproducibility was lower. A greater proportion of the performance measures from the standing LJs had low ICCs and/or high CVs values most likely owing to the complex nature of the LJ test. Practitioners and researchers can use most of the jump test parameters from the MARS with confidence to quantify changes in the functional ability of individuals over time, except for those relating to the rate of force development or change in momentum during countermovement phases of jumps.

  • 28.
    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.

  • 29.
    West, Daniel J.
    et al.
    Northumbria Univ, Sch Life Sci, Dept Sport & Exercise Sci, Newcastle Upon Tyne NE1 8ST, Tyne & Wear, England.
    Cook, Christian J.
    UK Sport, Res & Innovat, Bath, Avon, England.
    Beaven, C. Martyn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Kilduff, Liam P.
    Swansea Univ, Coll Engn, Swansea, W Glam, Wales.
    THE INFLUENCE OF THE TIME OF DAY ON CORE TEMPERATURE AND LOWER BODY POWER OUTPUT IN ELITE RUGBY UNION SEVENS PLAYERS2014In: JOURNAL OF STRENGTH AND CONDITIONING RESEARCH, ISSN 1533-4287, Vol. 28, no 6, p. 1524-1528Article in journal (Refereed)
    Abstract [en]

    Core temperature typically displays a low circadian in the morning before peaking later in the day, and these changes occur within small physiological ranges. Body temperature plays an important role in physical performance, and some athletes may be required to train and compete in both the morning and evening. However, the influence of the circadian change in body temperature and its influence on physical performance in elite athletes are unclear. This study examined the effects of the time of day on core temperature and lower body power output in elite rugby union sevens players. Sixteen elite rugby union sevens players completed morning (in AM) countermovement jump and core temperature (T-core) measurement, which were then repeated later the same day (in PM). Countermovement jump was processed for peak power output (PPO). Data were analyzed using paired samples t-test and Pearson's product moment correlation and are presented in mean +/- SD. T-core significantly increased from AM to PM (AM, 36.92 +/- 0.23 vs. PM, 37.18 +/- 0.188 degrees C; P < 0.001) with PPO significantly increasing from AM to PM in all 16 players (AM, 5248 +/- 366 vs. PM, 5413 +/- 361 W; P < 0.001). The delta change in T-core (0.26 +/- 0.138 degrees C) and PPO (164 +/- 78 W) was significantly related (r = 0.781; P < 0.001). In conclusion, small circadian changes in core temperature can influence physical performance in elite athletes. Coaches should seek to use strategies, which may raise morning body temperature to offset the circadian low in the morning.

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