miun.sePublikasjoner
Endre søk
Begrens søket
12 1 - 50 of 52
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Alricsson, Marie
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Linnaeus University, Kalmar.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Cronholm, Martin
    Scandinavian College of Naprapathic Manual Medicine, Stockholm.
    Olsson, Oscar
    Scandinavian College of Naprapathic Manual Medicine, Stockholm.
    Viklund, Peter
    Scandinavian College of Naprapathic Manual Medicine, Stockholm.
    Svantesson, Ulla
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Göteborgs Universitetet.
    Spinal alignment, mobility of the hip and thoracic spine and prevalence of low back pain in young elite cross-country skiers2016Inngår i: Journal of Exercise Rehabilitation, ISSN 2288-176X, Vol. 12, nr 1, s. 21-28, artikkel-id PMC4771149Artikkel i tidsskrift (Fagfellevurdert)
  • 2.
    Alricsson, Marie
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Linnaeus University.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Swedish Sports Confederat.
    Ekström, A.
    Linnaeus University.
    Ostenberg, A. Hafsteinsson
    Linnaeus University.
    Introducing Tabata intervals and stability exercises in school children by a school-based study2016Inngår i: European Journal of Public Health, ISSN 1101-1262, E-ISSN 1464-360X, Vol. 26, nr Issue suppl_1, s. 417-417Artikkel i tidsskrift (Fagfellevurdert)
  • 3.
    Andersson, Erik
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Swedish Olympic Committee, Stockholm, Sweden.
    Ørtenblad, Niels
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster, University of Southern Denmark, Odense, Denmark.
    Energy system contributions and determinants of performance in sprint cross-country skiing2017Inngår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 27, nr 4, s. 385-398Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To improve current understanding of energy contributions and determinants of sprint-skiing performance, 11 well-trained male cross-country skiers were tested in the laboratory for VO2max , submaximal gross efficiency (GE), maximal roller skiing velocity, and sprint time-trial (STT) performance. The STT was repeated four times on a 1300-m simulated sprint course including three flat (1°) double poling (DP) sections interspersed with two uphill (7°) diagonal stride (DS) sections. Treadmill velocity and VO2 were monitored continuously during the four STTs and data were averaged. Supramaximal GE during the STT was predicted from the submaximal relationships for GE against velocity and incline, allowing computation of metabolic rate and O2 deficit. The skiers completed the STT in 232 ± 10 s (distributed as 55 ± 3% DP and 45 ± 3% DS) with a mean power output of 324 ± 26 W. The anaerobic energy contribution was 18 ± 5%, with an accumulated O2 deficit of 45 ± 13 mL/kg. Block-wise multiple regression revealed that VO2 , O2 deficit, and GE explained 30%, 15%, and 53% of the variance in STT time, respectively (all P < 0.05). This novel GE-based method of estimating the O2 deficit in simulated sprint-skiing has demonstrated an anaerobic energy contribution of 18%, with GE being the strongest predictor of performance.

  • 4.
    Andersson, Erik
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Ørtenblad, Niels
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Energy contributions and pacing strategies of elite XC skiers during sprint skiing2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: At present, knowledge regarding energy contributions and pacing strategies during successive sprint time-trials (STTs) in cross-country (XC) skiing is limited and, therefore, the current study was designed to examine these parameters. The results shown have recently been published elsewhere (Andersson et al., 2016).METHODS: Ten well-trained male XC skiers performed four self-paced 1300-m STTs on a treadmill, separated by 45 min of recovery. The simulated STT course was divided into three flat (1°) sections (S1, S3 and S5) involving the double poling (DP) sub-technique interspersed with two uphill (7°) sections (S2 and S4) involving the diagonal stride (DS) sub-technique. Treadmill velocity and VO2 were monitored continuously and technique-specific gross efficiency (based on submaximal pre-tests) was used to estimate anaerobic energy production.RESULTS & DISCUSSION: The average STT performance time was 229 ± 9 s and the aerobic energy contribution was 82 ± 5%. A positive pacing strategy was used during all STTs, with 3-9% more time spent on the second half of the course (P < 0.05). In addition, the pacing strategy was regulated to the terrain, with substantially higher (~30%) metabolic rates, due to primarily higher anaerobic energy production, for uphill compared with flat skiing (P < 0.05). The individually fastest STT was more aggressively paced compared to the slowest STT (P < 0.05), which resulted in a higher O2 deficit rate (13 ± 4 versus 11 ± 4 mL/kg/min, P < 0.05), while the VO2 was similar (both 52 ± 3 mL/kg/min). These findings emphasise the importance of a fast start. The within-athlete coefficient of variation (CV) in performance time, VO2 and O2 deficit were 1.3 ± 0.4%, 1.4 ± 0.9% and 11.2 ± 4.9%, respectively, with the CV in O2 deficit explaining 69% of the CV in performance. The pacing strategies were highly consistent, with an average CV in speed of 3.4%.CONCLUSION: The fastest STT was characterized by more aggressive pacing and a greater anaerobic energy production. Although the individual performance time during the four STTs was highly consistent, the small within-athlete variability in performance was related to variations in anaerobic energy production.

  • 5.
    Andersson, Erik
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Ørtenblad, Niels
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Metabolic responses and pacing strategies during successive sprint skiing time trials2016Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 48, nr 12, s. 2544-2554Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: To examine the metabolic responses and pacing strategies during the performance of successive sprint time trials (STTs) in cross-country skiing. METHODS: Ten well-trained male cross-country skiers performed four self-paced 1300-m STTs on a treadmill, each separated by 45 min of recovery. The simulated STT course was divided into three flat (1°) sections (S1, S3 and S5) involving the double poling sub-technique interspersed with two uphill (7°) sections (S2 and S4) involving the diagonal stride sub-technique. Treadmill velocity and V˙O2 were monitored continuously and gross efficiency was used to estimate the anaerobic energy supply. RESULTS: The individual trial-to-trial variability in STT performance time was 1.3%, where variations in O2 deficit and V˙O2 explained 69% (P < 0.05) and 11% (P > 0.05) of the variation in performance. The first and last STTs were equally fast (228 ± 10 s), and ~ 1.3% faster than the second and the third STTs (P < 0.05). These two fastest STTs were associated with a 14% greater O2 deficit (P < 0.05), while the average V˙O2 was similar during all four STTs (86 ± 3% of V˙O2max). Positive pacing was used throughout all STTs, with significantly less time spent on the first than second course half. In addition, metabolic rates were substantially higher (~_30%) for uphill than for flat skiing, indicating that pacing was regulated to the terrain. CONCLUSIONS: The fastest STTs were characterized primarily by a greater anaerobic energy production, which also explained 69% of the individual variation in performance. Moreover, the skiers employed positive pacing and a variable exercise intensity according to the course profile, yielding an irregular distribution of anaerobic energy production.

  • 6.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Metabolic and Cardiovascular Responses During Variable Intensity Exercise2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Previous research investigating endurance sports from a physiological perspectivehas mainly used constant or graded exercise protocols, although the nature ofsports like cross-country skiing and road cycling leads to continuous variations inworkload. Current knowledge is thus limited as regards physiological responses tovariations in exercise intensity. Therefore, the overall objective of the present thesiswas to investigate cardiovascular and metabolic responses to fluctuations inexercise intensity during exercise. The thesis is based on four studies (Studies I-IV);the first two studies use a variable intensity protocol with cardiorespiratory andblood measurements during cycling (Study I) and diagonal skiing (Study II). InStudy III one-legged exercise was used to investigate muscle blood flow duringvariable intensity exercise using PET scanning, and Study IV was performed toinvestigate the transition from high to low exercise intensity in diagonal skiing,with both physiological and biomechanical measurements. The current thesisdemonstrates that the reduction in blood lactate concentration after high-intensityworkloads is an important performance characteristic of prolonged variableintensity exercise while cycling and diagonal skiing (Studies I-II). Furthermore,during diagonal skiing, superior blood lactate recovery was associated with a highaerobic power (VO2max) (Study II). Respiratory variables such as VE/VO2, VE/VCO2and RER recovered independently of VO2max and did not reflect the blood lactate oracid base levels during variable intensity exercise during either cycling or diagonalskiing (Studies I-II). There was an upward drift in HR over time, but not inpulmonary VO2, with variable intensity exercise during both prolonged cyclingand diagonal skiing. As a result, the linear HR-VO2 relationship that wasestablished with a graded protocol was not present during variable intensityexercise (Studies I-II). In Study III, blood flow heterogeneity during one-leggedexercise increased when the exercise intensity decreased, but remained unchangedbetween the high intensity workloads. Furthermore, there was an excessiveincrease in muscular VO2 in the consecutive high-intensity workloads, mainlyexplained by increased O2 extraction, as O2 delivery and blood flow remainedunchanged. In diagonal skiing (Study IV) the arms had a lower O2 extraction thanthe legs, which could partly be explained by their longer contact phase along withmuch higher muscle activation. Furthermore, in Study IV, the O2 extraction in botharms and legs was at the upper limit during the high intensity workload with nofurther margin for increase. This could explain why no excessive increase inpulmonary VO2 occurred during diagonal skiing (Study II), as increased O2extraction is suggested to be the main reason for this excessive increase in VO2(Study III).

  • 7.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Riksidrottsförbundet.
    Shooting efficiency for winners of World Cup and World Championship races in men’s and women’s biathlon: where is the cut-off?2018Inngår i: International Journal of Performance Analysis in Sport, ISSN 1474-8185, E-ISSN 1474-8185, Vol. 18, nr 4, s. 545-553Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The shooting profile of the biathlete is presented as the mean shooting percentage, which lacks valuable information for performance profiling. Hence, the aim of the study was to present a way of profiling biathlete shooting efficiency and profiling the men’s and women’s winners in the IBU World Cup and World Championships to clarify the fewest hits necessary to win races. Data from 106 competitions from two seasons were analysed and dichotomised. The proportions (p) (miss/hit) and 90% confidence interval were estimated, and binominal distributions for overall, standing and prone shooting. The women’s winners showed higher overall shooting efficiency than the men’s winners (−5.4 to −0.4 90%CI) season 2015/2016, due to lower prone shooting efficiency for the men. The men increased their overall shooting efficiency for the 2016/2017 season, compared to 2015/2016, due to increased prone shooting accuracy (−6.9 to −0.2 90%CI). The likelihood of winners missing three targets went from 14.7% to 3.7% and 3.5% to 4.3% for the 2015/2016 to 2016/2017 season for men and women, respectively. Overall, the men varied more than women between seasons due to reduced prone shooting efficiency, while the third miss appeared most critical for performance.

  • 8.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Tävlingslära2018Inngår i: Specialidrott: Tränings- och tävlingslära, SISU Idrottsböcker , 2018, s. 81-88Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 9.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. The Swedish Sports Confederation, Stockholm, Sweden.
    Alricsson, Marie
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Linnéuniversitetet.
    Svantesson, Ulla
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Sahlgrenska Akademin, Göteborgs Universitet.
    Using bilateral functional and anthropometric tests to define symmetry in cross-country skiers2017Inngår i: Journal of Human Kinetics, ISSN 1640-5544, E-ISSN 1899-7562, Vol. 60, nr 1, s. 9-18Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to evaluate the symmetry of anthropometry and muscle function in cross-country skiers and their association to vertical jumping power. Twenty cross-country skiers were recruited (21.7 ± 3.8 yrs, 180.6 ± 7.6 cm, 73.2 ± 7.6 kg). Anthropometric data was obtained using an iDXA scan. VO2max was determined using the diagonal stride technique on a ski treadmill. Bilateral functional tests for the upper and lower body were the handgrip and standing heel-rise tests. Vertical jump height and power were assessed with a counter movement jump. Percent asymmetry was calculated using a symmetry index and four absolute symmetry index levels. At a group level the upper body was more asymmetrical with regard to lean muscle mass (p = 0.022, d = 0.17) and functional strength (p = 0.019, d = 0.51) than the lower body. At an individual level the expected frequencies for absolute symmetry level indexes showed the largest deviation from zero for the heel-rise test (χ2 = 16.97, p = 0.001), while the leg lean mass deviated the least (χ2 = 0.42, p = 0.517). No relationships were observed between absolute symmetry level indexes of the lower body and counter movement jump performance (p > 0.05). As a group the skiers display a more asymmetrical upper body than lower body regarding muscle mass and strength. Interestingly at the individual level, despite symmetrical lean leg muscle mass the heel-rise test showed the largest asymmetry. This finding indicates a mismatch in muscle function for the lower body.

  • 10.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Swedish Sports Confederation.
    Born, Dennis
    Würzburg University, Germany.
    Stöggl, Thomas
    Salzburg University, Austria.
    Swarén, Mikael
    Kungliga Tekniska Högskolan.
    Performance analysis of trail running in undulating terrain2017Konferansepaper (Fagfellevurdert)
  • 11.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Danvind, Jonas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kvalitets- och maskinteknik.
    Sundström, David
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kvalitets- och maskinteknik.
    The effect of speed and gradient on running economy and oxygen uptake during downhill running2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Downhill running poses challenges were the gradient is of importance for energy cost and oxygen uptake. While demonstrated that downhill running at a slight gradient is most efficient, the energy cost increases with a steeper gradient (1). However, the additional effect of running speed has not been studied for downhill running. Therefore, the aim of the study was to analyse the combined effect of gradient and speed in downhill running on oxygen cost and running economy. METHODS:Runners (n=6) were recruited for the study and performed 1) VO2max and running economy (J·kg-1·m-1) tests and 2) an experimental running protocol at two speeds,12 km·h-1 and 80% of the speed at VO2max (V80) and three gradients (0, -5° and -10°). V80 was higher than 12 km·h-1 for all participants. All testing was performed on a large treadmill 3x5 m (Rodby, Sweden) that were controlled for speed and gradient. The experimental protocol was performed continuously with 5 min at each workload in a randomized order, 30 min in total. VO2 was measured throughout the experimental protocol using a mixing chamber (Moxus Metabolic Cart, USA). RESULTS:VO2 expressed as ml·kg-1·min-1 increased because of speed (F1,5=27.8, p=0.003) and decreased with gradient (F1,5=87.6, p<0.001). Between -5° and -10°, VO2 decreased less during V80 compared to 12 km·h-1 shown by an interaction (F2,10=7.9, p=0.009). However, speed did not influence running economy (F1,5=0.9, p=0.38) while gradient increased running economy (F1,5=90.1, p<0.001). A non-significant interaction effect suggests a shift in running economy between -5° and -10° depending on speed (F2,10=3.5, p=0.07). The running economy at V80 was higher compared to 12 km·h-1 at -5° but reversed at -10°. While a relation between running economy at V80 -10°, V80 -5° and 12 km·h-1 -10° (rs>0.88, p<0.019) was found, no relations between running economy on level terrain and steep downhill running (-10°) were recognised. CONCLUSION:While we found no effect on running economy from speed alone, we did see a shift in the running economy for different speeds at an increased downhill gradient. This indicates that a high speed (V80) is more efficient at moderate downhill gradients, while a lower speed (12 km·h-1) is more efficient in steeper downhill gradients. While previous research demonstrate that gradient is of great influence to running economy, the findings of this study suggest that speed also affects the running economy in downhill running.

  • 12.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Elgh, Tobias
    Styfberg, Pierre
    Fysiologi och träningslära2018Inngår i: Specialidrott: Tränings- och tävlingslära, SISU Idrottsböcker , 2018, s. 27-72Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 13.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    A comparison between elite and well trained cross-country skiers in physiological response to variations in intensity during prolonged exercise2008Inngår i: 13th Annual Congress of the European College of Sports Science, Cologne: Sportools , 2008, s. 522-Konferansepaper (Fagfellevurdert)
    Abstract [en]

     

    Introduction: Cross-country ski racing includes continual variations in intensity due to terrain and tactics {Mygind et al 1994; Norman et al 1989). Consequently, the recovery between periods with higher intensity might affect the outcome of the race. Both blood metabolites and respiratory variables are used for standard performance evaluations for endurance athletes, although there is a lack information if respiratory variables respond similar to blood lactate and acid/base values during prolonged variable exercise. Therefore, the aims with the present study were to 1) evaluate whether respiratory variables are associated with blood lactate and acid/base variables, 2) how/if these variables might predict physical performance and 3) whether a calculated heart rate-oxygen uptake (HR-VO2) relationship is valid during variable intensity exercise. Methods: 12 cross-country skiers classified as elite (E, n=6) and formerly well-trained (FWT, n=6) performed two roller ski tests. 1) An incremental test to establish maximal oxygen uptake (VO2max), maximum heart rate (HRmax) and lactate threshold (LT). Submaximal and maximal VO2 and HR during the incremental test were used for calculating the individual HR-VO2 linear relationship and 2) a 48-min long variable intensity protocol (VIP) at alternating exercise intensities, 90% (HI90) and 70% (MI70) of VO2max. Cardio-respiratory variables and venous blood samples were continuously collected throughout the VIP. Comparisons between E and FWT were performed using a two-tailed unpaired Student’s t-test and a ANCOVA analysis was used to determine which physiological variable best could prognosticate time to exhaustion (TTE). A simple linear regression was used to establish the relationship between HR and VO2. Results: Blood lactate concentrations [La] were higher and base excess [BE] lower for FWT from the first MI70 (P<0.05). FWT had augmented RER during all HI90 and an elevated VE/VO2 during the second and third HI90 in comparison to E (P<0.05). The expected HR were higher during the MI70 exercise intensities regardless of group affiliation (P<0.05). The blood [La] response predicted time to exhaustion earlier than respiratory variables (P<0.05). Discussion: Blood lactate and acid/base fluctuations were not reflected by RER and the ventilatory equivalents. Furthermore, blood lactate is to prefer, in comparison to ventilatory variables, to study performance related recovery processes during endurance exercise with variations in intensity. The expected HR-VO2 relationship was not valid during VIP.

     

  • 14.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Swedish Olymp Comm, Stockholm, Sweden.
    Stöggl, Thomas
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Salzburg Univ, Dept Sport Sci & Kinesiol, A-5020 Salzburg, Austria.
    The effects of prior high intensity double poling on subsequent diagonal stride skiing characteristics2015Inngår i: SpringerPlus, E-ISSN 2193-1801, Vol. 4, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: To investigate the influence of prior high intensity double poling (DP) on physiological and biomechanical responses during subsequent diagonal stride (DIA). Methods: Eight well-trained male cross-country skiers (age 22 ± 3 yr; VO2max 69 ± 3 ml · kg−1 · min−1) roller-skied on a treadmill sequentially for 3 min at 90% DIA VO2max (DIA1), 3 min at 90% DP VO2peak and 3 min at 90% DIA VO2max (DIA2). Cardio-respiratory responses were monitored continuously and gases and metabolites in blood from the a. femoralis, v. femoralis and v. subclavia determined. Pole and plantar forces and EMG from 6 lower- and upper-body muscles were measured. Results: VO2 decreased from DIA1 to DP and increased again to DIA2 (both P &lt; 0.05), with no difference between the DIA sessions. Blood lactate rose from DIA1 to DP to DIA2. O2 extraction was attenuated during DP (P &lt; 0.05), but was the same during DIA1 and DIA2. EMGRMS for arm muscles during poling phase, as well as peak pole force and cycle rate were higher, while leg muscle activity was lower during DP than both sessions of DIA (all P &lt; 0.05). The ratio of upper-/whole-body EMGRMS correlated negatively with O2 extraction in the arms during both sessions of DIA (P &lt; 0.05). Conclusions: In well-trained skiers skiing at high-intensity DP prior to DIA did not influence VO2, muscle activation or forces in the latter. At race intensity DP does not influence the distribution of work between upper- and lower-body during a subsequent bout of DIA. O2 extraction is coupled to technical skills during skiing.

  • 15.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Laaksonen, Marko
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Holmberg, H. -C
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Blood lactate recovery and respiratory responses during diagonal skiing of variable intensity2011Inngår i: European Journal of Sport Science, ISSN 1746-1391, E-ISSN 1536-7290, Vol. 11, nr 5, s. 317-326Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aims of the study were to investigate blood lactate recovery and respiratory variables during diagonal skiing of variable intensity in skiers at different performance levels. Twelve male cross-country skiers classified as elite (n=6; VO2max=73±3 ml. kg-1. min-1) or moderately trained (n=6; VO2max=61±5 ml. kg-1. min-1) performed a 48-min variable intensity protocol on a treadmill using the diagonal stride technique on roller skis, alternating between 3 min at 90% and 6 min at 70% of VO2max. None of the moderately trained skiers were able to complete the variable intensity protocol and there was a difference in time to exhaustion between the two groups (elite: 45.0±7.3 min; moderately trained: 31.4±10.4 min) (P&lt;0.05). The elite skiers had lower blood lactate concentrations and higher blood base excess concentrations at all 70% workloads than the moderately trained skiers (all P&lt;0.05). In contrast, VE/VO2 and VE/VCO2 at the 70% VO2max workloads decreased independently of group (P&lt;0.05). Partial correlations showed that VO2max was related to blood lactate at the first and second intervals at 70% of VO2max (r=-0.81 and r=-0.82; both P&lt;0.01) but not to VE/VO2, VE/VCO2 or the respiratory exchange ratio. Our results demonstrate that during diagonal skiing of variable intensity, (1) elite skiers have superior blood lactate recovery compared with moderately trained skiers, who did not show any lactate recovery at 70% of VO2max, suggesting it is an important characteristic for performance; and (2) the decreases in respiratory exchange ratio, VE/VO2, and VE/VCO2 do not differ between elite and moderately trained skiers.

  • 16.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Lindberg, Thomas
    Tester och mätmetoder2018Inngår i: Specialidrott: Tränings- och tävlingslära, SISU Idrottsböcker , 2018, s. 73-80Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 17.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Pettersson, Sofia
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Performance predicting factors in prolonged exhausting exercise of varying intensity2007Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 99, nr 4, s. 423-429Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several endurance sports, e.g. road cycling, have a varying intensity profile during competition. At present, few laboratory tests take this intensity profile into consideration. Thus, the purpose of this study was to examine the prognostic value of heart rate (HR), lactate (La−1), potassium (K+), and respiratory exchange ratio (RER) performance at an exhausting cycling exercise with varying intensity. Eight national level cyclists performed two cycle tests each on a cycle ergometer: (1) a incremental test to establish VO2max, maximum power (W max), and lactate threshold (VO2LT), and (2) a variable intensity protocol (VIP). Exercise intensity for the VIP was based upon the VO2max obtained during the incremental test. The VIP consisted of six high intense (HI) workloads at 90% of VO2max for 3 min each, interspersed by five middle intense (MI) workloads at 70% of VO2max for 6 min each. VO2 and HR were continuously measured throughout the tests. Venous blood samples were taken before, during, and after the test. Increases in HR, La-, K+, and RER were observed when workload changed from MI to HI workload (P < 0.05). Potassium and RER decreased after transition from HI to MI workloads (P < 0.05). There was a negative correlation between time to exhaustion and decrease in La- concentration during the first MI (r = −0.714; P = 0.047). Furthermore, time to exhaustion correlated with VO2LT calculated from the ramp test (r = 0.738; P = 0.037). Our results suggest that the magnitude of decrease of La−1 between the first HI workload and the consecutive MI workload could predict performance during prolonged exercise with variable intensity

  • 18.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Stöggl, Thomas
    Carlsson, Lars
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Dovrén, Louise
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    The relationship between oxygen extraction in the arms and legs to force and exercise intensity in diagonal skiing2009Inngår i: Proceedings of the 14th Annual Congress of European College of Sports Science / [ed] Loland, S., Bø, K., Fasting, K., Hallén, J., Ommundsen, Y., Roberts, G., Tsolakidis, E., Oslo: Gamlebyen Grafiske AS , 2009Konferansepaper (Fagfellevurdert)
  • 19.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Stöggl, Thomas
    Department of Sport Science and Kinesiology, University of Salzburg, Austria.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Biomechanical influenced differences in O2 extraction in diagonal skiing: arm versus leg2010Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 42, nr 10, s. 1899-1908Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biomechanically Influenced Differences in O-2 Extraction in Diagonal Skiing: Arm versus Leg. Med. Sci. Sports Exerc., Vol. 42, No. 10, pp. 1899-1908, 2010. Purpose: This study aimed to determine whether the differences in oxygen extraction and lactate concentration in arms and legs during cross-country skiing are related to muscle activation or force production and how these differences are influenced by a reduction in exercise intensity. Methods: Nine well-trained male cross-country skiers (age = 22 +/- 3 yr, (V) over dotO(2max) = 5.3 +/- 0.3 L.min(-1) and 69 +/- 3 mL.kg(-1).min(-1)) performed diagonal skiing on a treadmill for 3 min at 90% followed by 6 min at 70% of (V) over dotO(2max). During the final minute of each workload, arterial, femoral, and subclavian venous blood was collected for determination of blood gases, pH, and lactate. EMG was recorded from six upper-and lower-body muscles, and leg and pole forces were measured. Cardiorespiratory variables were monitored continuously. Results: Oxygen extraction in the legs was higher than that in the arms at both 90% and 70% of (V) over dotO(2max) (92% +/- 3% vs 85% +/- 6%, P < 0.05 and 90% +/- 3% vs 78% +/- 8%, P < 0.001). This reduction with decreased workload was more pronounced in the arms (-9.8% +/- 7.7% vs -3.2% +/- 3.2%, P < 0.01). EMGRMS for the arms was higher, and pole ground contact time was greater than the corresponding values for the legs (both P < 0.01). At both intensities, the blood lactate concentration was higher in the subclavian than that in the femoral vein but was lowered more in the subclavian vein when intensity was reduced (all P < 0.001). Conclusions: The higher muscle activation (percentage of maximal voluntary isometric contraction) in the arms and the longer ground contact time of the poles than the legs contribute to the lower oxygen extraction and elevated blood lactate concentration in the arms in diagonal skiing. The better lactate recovery in the arms than that in the legs is aided by greater reductions in muscle activation and pole force when exercise intensity is reduced.

  • 20.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Stöggl, Thomas
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    NO EXCESS VO2 DURING WHOLE-BODY HIGH INTENSITY EXERCISE IN WELL-TRAINED CROSS-COUNTRY SKIERS2012Inngår i: Book of Abstracts of the 17th Annual Congress of the European College of Sport Science / [ed] Meeusen, R., Duchateau, J., Roelands, B., Klass, M., De Geus, B., Baudry, S., Tsolakidis, E., 2012, s. 54-54Konferansepaper (Fagfellevurdert)
  • 21.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Swarén, Mikael
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Låt underlaget bestämma löpsteget2014Inngår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, nr 4, s. 8-11Artikkel i tidsskrift (Annet vitenskapelig)
  • 22.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Swarén, Mikael
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Required shooting efficiency to win World Cup and World Championship Biathlon races during the 2015-2016 season2016Konferansepaper (Fagfellevurdert)
  • 23.
    Björklund, Glenn
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. The Swedish Sports Confederation, Stockholm, Sweden.
    Swarén, Mikael
    Kungliga Tekniska Högskolan.
    Born, Dennis-Peter
    Swiss Federal Institute of Sport, Magglingen, Switzerland.
    Stöggl, Thomas
    University of Salzburg, Salzburg, Austria.
    Biomechanical Adaptations and Performance Indicators in Short Trail Running2019Inngår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, artikkel-id 506Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Our aims were to measure anthropometric and oxygen uptake (V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; font-size: 20px; 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; color: rgb(62, 61, 64); font-family: Georgia, "Times New Roman", Times, serif; position: relative; outline: 0px !important;">V˙V˙O2) variables in the laboratory, to measure kinetic and stride characteristics during a trail running time trial, and then analyse the data for correlations with trail running performance. Runners (13 men, 4 women: mean age: 29 ± 5 years; stature: 179.5 ± 0.8 cm; body mass: 69.1 ± 7.4 kg) performed laboratory tests to determine V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; font-size: 20px; 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; color: rgb(62, 61, 64); font-family: Georgia, "Times New Roman", Times, serif; position: relative; outline: 0px !important;">V˙V˙O2 max, running economy (RE), and anthropometric characteristics. On a separate day they performed an outdoor trail running time trial (two 3.5 km laps, total climb: 486 m) while we collected kinetic and time data. Comparing lap 2 with lap 1 (19:40 ± 1:57 min vs. 21:08 ± 2:09 min, P < 0.001), runners lost most time on the uphill sections and least on technical downhills (-2.5 ± 9.1 s). Inter-individual performance varied most for the downhills (CV > 25%) and least on flat terrain (CV < 10%). Overall stride cycle and ground contact time (GCT) were shorter in downhill than uphill sections (0.64 ± 0.03 vs. 0.84 ± 0.09 s; 0.26 ± 0.03 vs. 0.46 ± 0.90 s, both P < 0.001). Force impulse was greatest on uphill (248 ± 46 vs. 175 ± 24 Ns, P < 0.001) and related to GCT (r = 0.904, P< 0.001). Peak force was greater during downhill than during uphill running (1106 ± 135 vs. 959 ± 104 N, P< 0.01). Performance was related to absolute and relative V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; font-size: 20px; 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; color: rgb(62, 61, 64); font-family: Georgia, "Times New Roman", Times, serif; position: relative; outline: 0px !important;">V˙V˙O2 max (P < 0.01), vertical uphill treadmill speed (P < 0.001) and fat percent (P < 0.01). Running uphill involved the greatest impulse per step due to longer GCT while downhill running generated the highest peak forces. V&#x2D9;" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; font-size: 20px; 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; color: rgb(62, 61, 64); font-family: Georgia, "Times New Roman", Times, serif; position: relative; outline: 0px !important;">V˙V˙O2 max, vertical running speed and fat percent are important predictors for trail running performance. Performance between runners varied the most on downhills throughout the course, while pacing resembled a reversed J pattern. Future studies should focus on longer competition distances to verify these findings and with application of measures of 3D kinematics.

  • 24.
    Born, Dennis
    et al.
    University of Würzburg.
    Stöggl, Thomas
    University of Salzburg, Salzburg, Austria.
    Swarén, Mikael
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Near-Infrared Spectroscopy: More Accurate Than Heart Rate for Monitoring Intensity in Running in Hilly Terrain2017Inngår i: International Journal of Sports Physiology and Performance, ISSN 1555-0265, E-ISSN 1555-0273, Vol. 12, nr 4, s. 440-447Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose:

    To 1) investigate the cardiorespiratory and metabolic response of trail running and 2) evaluate whether heart rate (HR) adequately reflects the exercise intensity or whether the tissue saturation index (TSI) could provide a more accurate measure when running in hilly terrain.

    Methods:

    Seventeen competitive runners (female: n=4, V’O2max: 55±6 mL·kg−1·min−1; male: n=13, V’O2max: 68±6 mL·kg−1·min−1) performed a time trial on an off-road trail course. The course was made up of two laps covering a total distance of 7 km and included six steep up- and downhill sections with an elevation gain of 486 m. All runners were equipped with a portable breath-by-breath gas analyzer, HR belt, global positioning system receiver and near-infrared spectroscopy (NIRS) device to measure the TSI.

    Results:

    During the trail run, the exercise intensity within the uphill and downhill sections was 94±2% and 91±3% of HRmax, 84±8% and 68±7% of V’O2max, respectively. The oxygen uptake (V’O2) increased within the uphill and decreased within the downhill sections (P< .01). While HR was unaffected by the altering slope conditions, the TSI was inversely correlated to the changes in V’O2 (r = - .70, P< .05).

    Conclusions:

    The HR was unaffected by the continuously changing exercise intensity, however, the TSI reflected the alternations in V’O2. Recently used exclusively for scientific purpose, this NIRS based variable may offer a more accurate alternative to HR to monitor running intensity in the future, especially for training and competition in hilly terrain.

  • 25. Born, Dennis
    et al.
    Stöggl, Thomas
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Swarén, Mikael
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Sperlich, Billy
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Is heart rate a valid measure to monitor exercise intensity during trail running in undulating terrain?2015Konferansepaper (Fagfellevurdert)
  • 26.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Haughey, Helena
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Pettersson, Sofia
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    High hemoglobin levels in divers may be a result of apnea induced EPO-production2005Inngår i: FASEB JOURNAL, 2005, s. A211-A212Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Oxygen storage capacity is important for apneic duration and affects performance in endurance sports. We studied if hemoglobin concentration (Hb) was different in divers compared to endurance athletes and untrained subjects and if any differences could be connected to training-induced erythropoietin (EPO) -production. We first compared Hb in 3 groups of subjects: 13 elite apneic divers (35±4 years), 13 elite cross-country skiers (20±1 years) and 23 untrained subjects (29±1 years) with similar weight and height. After 20 min of horizontal rest blood samples were drawn and analysed for Hb using standard methods. In a second experiment, we compared EPO levels before and after a series of 15 maximal apneas in air in 9 previously untrained volunteers (302 years). Apneas were spaced by 2 minutes, the last minute with hyperventilation to produce durations long enough to induce hypoxia. Values were also compared to the EPO levels of a control day without apneas. The apneic divers had higher Hb than untrained subjects (P<0.05) and skiers (P<0.01). After apnea training in untrained subjects EPO levels increased in all subjects, with a mean peak value after 3 h, where the increase was 135 % of the pre apnea value (P<0.05). No increase was observed during the same time period of the control day. We concluded that higher Hb levels in apneic divers may be a result of enhanced EPO-production due to the apnea training.

  • 27.
    de Bruijn, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Richardson, Matthew
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Haughey, Helena
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hemoglobin levels in elite divers, elite skiers and untrained humans2004Konferansepaper (Annet vitenskapelig)
  • 28.
    Ekström, Annika
    et al.
    Linnéuniversitetet, Kalmar/Växjö.
    Hafsteinsson Östenberg, Anna
    Linnéuniversitetet, Växjö.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Alricsson, Marie
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. Linnéuniversitetet, Kalmar/Växjö.
    The effects of introducing Tabata interval training and stability exercises to school children as a school-based intervention program2019Inngår i: International Journal of Adolescent Medicine and Health, ISSN 0334-0139, E-ISSN 2191-0278, Vol. 31, nr 4, artikkel-id 20170043Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background

    Physical activities during leisure time as well as school hours have changed over the past few years, with adolescents being less physically active and adopting a sedentary lifestyle.

    Objective

    The overall objective of this mixed-methods study was to evaluate the feasibility of introducing a 4-min Tabata interval training into a lower secondary school context. A further aim was to evaluate the possible effects on: coordination, balance, and strength.

    Methods

    The study was conducted as an intervention study with a mixed-method approach. Forty-three children, aged 7–9 years, participated in the intervention group. Additionally, 13 children were recruited as a control group. The intervention itself was delivered by the teachers and was performed for 4-min every day in a classroom setting. All participants performed physical tests before and after the intervention period to evaluate the Tabata training. After the completion of the 6-week Tabata interval training, the four teachers were interviewed.

    Results

    The push-ups (p = 0.004), kneeling push-ups (p = 0.03), and standing long jump (p = 0.01) improved in the intervention group after 6 weeks. No differences were observed between the genders. The teachers experienced that it worked well to integrate the Tabata interval training in the classroom setting.

    Conclusion

    After 6 weeks, a school-based Tabata intervention program improved physical performance. The teachers saw no obstacles in including the Tabata intervention program in a classroom setting and pointed out several positive aspects such as an increased energy level and development in the children’s movement patterns.

  • 29.
    Elgh, Tobias
    et al.
    Riksidrottsförbundet.
    Lindberg, Thomas
    Riksidrottsförbundet.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Metabolic response during submaximal and maximal ergometer tests in elite sprint kayakers2017Konferansepaper (Fagfellevurdert)
  • 30.
    Hansen, Elisabeth
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. The Swedish Sports Confederation.
    Vinberg, Stig
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Workplace Health Interventions and Physical Fitness Status among Managers of Small-Scale Enterprises in Norway and Sweden2016Inngår i: Health, ISSN 1949-4998, E-ISSN 1949-5005, Vol. 8, s. 1697-1712Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background : The ability of managers of small-scale enterprises (SSEs) to prioritize health, working conditions, and their own physical fitness is an important issue for workplace health promotion in Norway and Sweden, where most owner-manager positions are in SSEs. Aim : To assess the physical fitness status of SSE managers compared to a norm population and to study changes in physical fitness status, self-reported physical activity, and sickness outcomes after workplace health interventions. Methods : The study allocated SSE managers to either an intervention or a reference group. The intervention, over twelve months, consisted of motivational input related to lifestyle and physical activity through tests and feedback, individual support, and courses on health and psychosocial working conditions. The participants (N = 28) completed health screening checks, questionnaires and testing before and after the intervention. Results : SSE managers in the study had positive outcomes for BMI levels and strength compared to the norm population, while percentage of fat for both men and women indicated poor results. There were no further improvements in the intervention group after comparison with the reference group. Separately, both groups seemed to improve strength and body composition. Conclusion : Workplace health interventions with essentially motivational components may increase SSE managers’ attention to physical fitness, but appear to have limited effects on objective and subjective physical fitness outcomes.

  • 31.
    Holmberg, Hans-Christer
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Vintersportcentrum: En resurs för utveckling och uppföljning av olympiska vintergrenar2004Inngår i: Svensk Idrottsforskning: organ för Centrum för idrottsforskning, ISSN 1103-4629, nr 1, s. 10-14Artikkel i tidsskrift (Annet vitenskapelig)
  • 32.
    Holmberg, Hans-Christer
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Lindinger, Stefan
    University of Salzburg, Austria.
    Stöggl, Thomas
    University of Salzburg, Austria.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Muller, Erich
    University of Salzburg, Austria.
    Contribution of the legs to double-poling performance in elite cross country skiers2006Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 38, nr 10, s. 1853-1860Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: In the classical style of cross-country skiing, the double-poling (DP) technique, which is regarded as an upper-body exercise, is used on the flatter parts of a course. Limited biomechanical and physiological data are available about DP compared with other cross-country skiing techniques. The purpose of the present study was to evaluate the possible role of the lower body during DP. METHODS: Eleven elite cross-country skiers performed two incremental tests using DP roller skiing at 1 degree inclination on a treadmill with or without locking the knee and ankle joints (DPLOCKED and DPFREE). Maximal and peak oxygen uptake (VO2max and VO2peak) during classic diagonal skiing and DP, respectively, were measured. In addition, heart rate, blood lactate concentration, and maximal DP velocity (Vmax) were determined. Pole-ground reaction forces and joint angles (elbow, hip, knee, and ankle) were analyzed. RESULTS: The skiers obtained 7.7% higher VO2peak, 9.4% higher Vmax, and 11.7% longer time to exhaustion during DPFREE compared with DPLOCKED (all P < 0.05). There was a higher heart rate and blood lactate concentration in DPLOCKED at submaximal stages (all P < 0.05), with no difference in oxygen consumption. At 85% Vmax, corresponding to approximately 81% VO2peak FREE, the differences in physiological variables were accompanied by a 13.6% higher poling frequency, a 4.9% shorter poling phase, 13.3% shorter recovery phase, and 10.9% lower relative pole force in DPLOCKED (all P < 0.05). CONCLUSIONS: Movements of the knee and ankle joints are an integrative part in the skillful use of the DP technique, and restriction of the motion in these joints markedly affects both biomechanical and physiological variables, impairing DP performance.

  • 33.
    Jensen, Kurt
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Höök, Martina
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Wedholm, Lars
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    How work economy changes during a summer season with roller skiing training and its influence on performance2012Inngår i: Science and Skiing V / [ed] Erich Mueller, Stefan Lindinger, Thomas Stöggl, Meyer & Meyer Sport, 2012, s. 523-529Kapittel i bok, del av antologi (Fagfellevurdert)
  • 34.
    Jensen, Kurt
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Höök, Martina
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Wedholm, Lars
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    How work efficiency changes during a summer season with roller skiing training and its influence on performace2010Inngår i: Proceedings for the fifth international conference on Science and Skiing / [ed] Erich Mueller, Salzburg: Meyer & Meyer Sport, 2010, s. 75-Konferansepaper (Fagfellevurdert)
  • 35.
    Kårström, Andreas
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    The effect of carbohydrate mouth rinse on simulated XC-sprint performance2015Konferansepaper (Fagfellevurdert)
  • 36.
    Laaksonen, Marko
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Heinonen, Ilkka
    Turku PET Centre, University of Turku, Finland.
    Kemppainen, Jukka
    Turku PET Centre, University of Turku, Finland.
    Knuuti, Juhani
    Turku PET Centre, University of Turku, Finland.
    Kyröläinen, Heikki
    University of Jyväskylä, Finland.
    Kalliokoski, Kari
    Turku PET Centre, University of Turku, Finland.
    Perfusion heterogeneity does not explain excess muscle oxygen uptake during variable intensity exercise2010Inngår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 30, nr 4, s. 241-249Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The association between muscle oxygen uptake (VO2) and perfusion or perfusion heterogeneity (relative dispersion, RD) was studied in eight healthy male subjects during intermittent isometric (1 s on, 2 s off) one-legged knee-extension exercise at variable intensities using positron emission tomography and a-v blood sampling. Resistance during the first 6 min of exercise was 50% of maximal isometric voluntary contraction force (MVC) (HI-1), followed by 6 min at 10% MVC (LOW) and finishing with 6 min at 50% MVC (HI-2). Muscle perfusion and O2 delivery during HI-1 (26 ± 5 and 5·4 ± 1·0 ml 100 g−1 min−1) and HI-2 (28 ± 4 and 5·8 ± 0·7 ml 100 g−1 min−1) were similar, but both were higher (P<0·01) than during LOW (15 ± 3 and 3·0 ± 0·6 ml 100 g−1 min−1). Muscle VO2 was also higher during both HI workloads (HI-1 3·3 ± 0·4 and HI-2 4·1 ± 0·6 ml 100 g−1 min−1) than LOW (1·4 ± 0·4 ml 100 g−1 min−1; P<0·01) and 25% higher during HI-2 than HI-1 (P<0·05). O2 extraction was higher during HI workloads (HI-1 62 ± 7 and HI-2 70 ± 7%) than LOW (45 ± 8%; P<0·01). O2 extraction tended to be higher (P = 0·08) during HI-2 when compared to HI-1. Perfusion was less heterogeneous (P<0·05) during HI workloads when compared to LOW with no difference between HI workloads. Thus, during one-legged knee-extension exercise at variable intensities, skeletal muscle perfusion and O2 delivery are unchanged between high-intensity workloads, whereas muscle VO2 is increased during the second high-intensity workload. Perfusion heterogeneity cannot explain this discrepancy between O2 delivery and uptake. We propose that the excess muscle VO2 during the second high-intensity workload is derived from working muscle cells.

  • 37.
    Laaksonen, Marko
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Pettersson, Sofia
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Performance predicting factors during prolonged non-steady state cycling2006Inngår i: Book of Abstracts of the 11th Annual Congress of the European College of Sport Science in Lausanne, Switzerland from 5-8 July 2006, 2006Konferansepaper (Fagfellevurdert)
  • 38.
    Laaksonen, Marko S
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Heinonen, Ilkka
    Turku PET Centre, University of Turku, Finland.
    Kemppainen, Jukka
    Turku PET Centre, University of Turku, Finland.
    Knuuti, Juhani
    Turku PET Centre, University of Turku, Finland.
    Kyrölainen, Heikki
    Neuromuscular Research Centre, University of Jyväskylä, Finland.
    Kalliokoski, Kari K
    Turku PET Centre, University of Turku, Finland.
    Effects of intensity variation and muscle fatigue during knee-extension exercise on muscle perfusion and oxygen uptake2008Inngår i: Book of Abstracts of the 11th Annual Congress of the European College of Sport Science in Estoril, Portugal, from 9-12 July 2008, 2008Konferansepaper (Annet vitenskapelig)
  • 39.
    McGawley, Kerry
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Platt, Simon
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Beaven, Martyn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    The validity and reliability of a four-minute running time trial in assessing VO2max and performance2015Konferansepaper (Fagfellevurdert)
    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.

  • 40.
    Richardson, Matthew
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    de Bruijn, Robert
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Haughey, Helena
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Schagatay, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Increase of hemoglobin concentration after maximal apneas in divers, skiers and untrained humans2005Inngår i: Canadian Journal of Applied Physiology, ISSN 1066-7814, Vol. 30, nr 3, s. 276-281Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Apnea is physiologically stressful and can within a short time frame pose a threat to survival. To sustain prolonged apnea, oxygen use should be minimized and its storage maximized. Two mechanisms known to have this effect are the cardiovascular diving response, directing the available oxygen selectively to the heart and brain, and spleen contraction increasing the circulating erythrocyte volume and thereby gas storage capacity. Spleen contraction is also observed after maximal exercise, and is thought to enhance aerobic performance. While the cardiovascular diving response is known to be more pronounced after apnea training, spleen contraction has not been studied in conjunction with apnea training or other types of training. The aim of the present investigation is to study the hematological responses to apnea performed during rest by elite apneic divers, by elite cross-country skiers and by untrained subjects. After 20 min of rest, subjects performed 3 maximal apneas spaced by 2 min normal breathing intervals. Blood samples were drawn before, directly after, and 10 min after the apnea series and hemoglobin concentration was measured. All groups responded to maximal apneas with an increase in hemoglobin concentration, which had disappeared after 10 min of recovery. The increase in hemoglobin concentration was more pronounced in the apneic divers (4g/L) than in skiers (3g/L) and untrained subjects (2g/L; P < 0.05). All groups prolonged their apneic times through the series, but the increase was most evident for the divers versus both the skiers (P < 0.05) and untrained subjects (P < 0.01). The results suggest that these responses could be more pronounced as a result of apnea training.

  • 41.
    Schagatay, Erika
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Björklund, Glenn
    Rydh, F
    VO2 slow component abolished after warm up with apneas2009Inngår i: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009, 2009Konferansepaper (Fagfellevurdert)
  • 42.
    Schagatay, Erika
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Hubinette, A
    Klockervold, I
    Björklund, Glenn
    Enqvist, Jonas
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    The effects of 70 days of skiing across Greenland on body composition, cold- and altitude tolerance and work performance in two elderly men2009Inngår i: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009, 2009Konferansepaper (Fagfellevurdert)
  • 43.
    Sjöström, Rita
    et al.
    Umeå Universitet; Östersund sjukhus.
    Söderström, Lars
    Östersunds sjukhus.
    Klockmo, Carolina
    Kommunförbundet Västernorrland.
    Patrician, Alexander
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Sandström, Thomas
    Umeå Universitet.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Hanstock, Helen
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Stenfors, Nikolai
    Umeå Universitet.
    Qualitative identification and characterisation of self-reported symptoms arising in humans during experimental exposure to cold air2019Inngår i: International Journal of Circumpolar Health, ISSN 2242-3982, E-ISSN 2242-3982, Vol. 78, nr 1, artikkel-id 1583528Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Exposure to cold air is associated with increased morbidity and mortality in the general population. It is difficult to study the effects of whole-body exposure to cold air under controlled conditions in real life. Objectives: The aim of this study was to (1) explore and describe the experience of symptoms in humans during experimental and controlled exposures to cold air, by using controlled environmental chamber exposures and qualitative methodology, and to (2) categorise the symptoms. Method: The study used a randomised, double blind design, in which 34 subjects undertook rest and moderate-intensity exercise in an environmental chamber set to two or three different temperatures (0, −10, and −17°C) on separate occasions. During the chamber exposures, subjects were interviewed. Qualitative content analysis was selected as the method of analysis. Findings: Subjects reported 50 distinct symptoms during the exposures. The symptoms were grouped into ten sub-categories and two major categories; airway versus whole-body symptoms. Conclusion: We have identified a broad range of symptoms in humans undertaking rest and moderate-intensity exercise at sub-zero temperatures. The symptoms and their categories may well be used to more extensively and quantitatively map cold-induced morbidity.

  • 44.
    Stöggl, Thomas
    et al.
    University of Salzburg, Salzburg, Austria.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. The Swedish Sports Confederation, Stockholm, Sweden.
    High intensity interval training leads to greater improvements in acute heart rate recovery and anaerobic power as high volume low intensity training2017Inngår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, artikkel-id 562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of the current study was to explore if training regimes utilizing diverse training intensity distributions result in different responses on neuromuscular status, anaerobic capacity/power and acute heart rate recovery (HRR) in well-trained endurance athletes.

    Methods: Thirty-six male (n = 33) and female (n = 3) runners, cyclists, triathletes and cross-country skiers [peak oxygen uptake: (VO2peak): 61.9 ± 8.0 mL·kg−1·min−1] were randomly assigned to one of three groups (blocked high intensity interval training HIIT; polarized training POL; high volume low intensity oriented control group CG/HVLIT applying no HIIT). A maximal anaerobic running/cycling test (MART/MACT) was performed prior to and following a 9-week training period.

    Results: Only the HIIT group achieved improvements in peak power/velocity (+6.4%, P < 0.001) and peak lactate (P = 0.001) during the MART/MACT, while, unexpectedly, in none of the groups the performance at the established lactate concentrations (4, 6, 10 mmol·L−1) was changed (P > 0.05). Acute HRR was improved in HIIT (11.2%, P = 0.002) and POL (7.9%, P = 0.023) with no change in the HVLIT oriented control group.

    Conclusion: Only a training regime that includes a significant amount of HIIT improves the neuromuscular status, anaerobic power and the acute HRR in well-trained endurance athletes. A training regime that followed more a low and moderate intensity oriented model (CG/HVLIT) had no effect on any performance or HRR outcomes.

  • 45.
    Stöggl, Thomas
    et al.
    Department of Sport Science and Kinesiology, University of Salzburg, Austria.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Biomechanical determinants of oxygen extraction during cross-country skiing2013Inngår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, nr 1, s. e9-e20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To determine the relationship of muscle activation, force production, and cycle characteristics to O2 extraction during high- and lower-intensity double poling (DP), nine well-trained male cross-country skiers performed DP on a treadmill for 3 min at 90% VO2peak followed by 6 min at 70%. During the final minute at each workload, arterial, femoral, and subclavian venous blood were collected for determination of partial pressure of O2, partial pressure of CO2, pH, and lactate. Electromyography (EMG) was recorded from six upper and lower body muscles, leg and pole forces were measured, and cardiorespiratory variables were monitored continuously. O2 extraction was associated with time point of peak pole force (PFpeak), duration of recovery, EMG activity, and lower body use. Arm O2 extraction was lower than in the legs at both intensities (P < 0.001) and was reduced to a lesser extent upon decreasing the workload (P < 0.05). Arm root-mean-square EMG was higher during the poling phase and entire cycle compared with the legs (P < 0.001). Blood lactate was higher in the subclavian than in femoral vein and artery (P < 0.001) and independent of intensity. O2 extraction was correlated to low muscle activation, later PFpeak, prolonged poling time, and extensive dynamic lower body use. Cycle rate and recovery time were associated with O2 extraction during high-intensity exercise only.

  • 46.
    Swarén, Mikael
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. KTH.
    Born, Dennis
    Julius-Maximilians-Universität Würzburg.
    Stöggl, Thomas
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Salzburg University, Department of Sport Science and Kinesiology.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Biomechanical 3D field measurements of trail runners2015Konferansepaper (Fagfellevurdert)
  • 47.
    Swarén, Mikael
    et al.
    KTH ; Swedish Olympic Academy.
    Fredrik, Hillergren
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Larsson, Andreas
    SkateCoach AB.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Swedish Sports Confederation.
    Key performance indicators of ice hockey sprint performance2018Inngår i: Journal of Sports Sciences: BASES Conference 2018 – Programme and Abstracts, Routledge, 2018, Vol. 36 (S1), s. 1-94Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Ice hockey is a physical demanding sport with high intensity and repetitive start and stop movements. Hence, players need to have excellent physical condition and ice skating skills with good acceleration and sprint capacities. However, little biomechanical research has been conducted on elite ice hockey players to analyse applicable key performance indicators of skating acceleration and short sprint performance. The aim of the study was to collect plantar forces data of elite ice hockey players during short sprints in order to analyse and identify plausible performance indicators. With institutional ethics approval, twelve professional male ice hockey players, (Age 22.8 ± 5.2 years, height 185.6 ± 5.0 cm, weight 86.9 ± 6.2 kg) from the Swedish Hockey League participated in the study. Following an individual warm up, each player performed three maximal sprints (18.4 m) from a stationary position, with three minutes of rest between each sprint. Sprint time was collected with timing gates (Brower Timing system, USA). The best trial for each player was chosen for further analysis. Plantar forces were collected at 100 Hz with pressure insoles (Novel GmbH, Germany), placed in both skates (Buckeridge et al., 2015, PLOS ONE, 10, 5). Analyses were made for stride rate, symmetry left-right, contact time, force production and impulse. Only the step frequency, 3.35 ± 0.38 strides/s was correlated to skating performance (r = -0.6, P < 0.05). For the second to seventh step, the mean contact time was 0.26 ± 0.04 s, the mean force was 844 ± 152 N and the mean peak force was 1335 ± 224 N. The mean impulse was 230 ± 52 Ns and the group showed greater force production for the left leg compared to the right leg −2.07 ± 9.08 %. The present study is the first study to analyse plantar forces on professional ice hockey players. The significance of stride rate is in line with previous research (Renaud et al., 2017, Sports Engineering, 20, 255–266) whereas the plantar force production is higher, compared to findings by Buckeridge et al. (2015). This is likely explained by the use of higher skilled players in the present study. Still, plantar force production is not significant for performance which points to the importance of skating kinematics and/or shear forces. Hence, the combination of kinetics and 3D kinematics on ice is important to enhance the knowledge about skating performance of elite ice hockey players as well as developing a kinetic measurement system to measure shear forces in combination with plantar forces.

  • 48.
    Swarén, Mikael
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Larsson, Oscar
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Using telecasting to identify key performance indicators in alpine skiing and evaluate the inter-analyst reliability of alpine ski coaches2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    ntroduction The most frequently used analysis method in alpine skiing is video footage. However, using video footage to identifying key performance indicators (KPIs) and other characteristics are difficult as each coach analyzes video footage in a subjective manner, which decreases the reliability of the analyses. Even though alpine skiing is a “closed sport”, without any external disturbing moments, each race is unique therefore never identical. It is thus difficult for coaches to know the validity and reliability of their analyses as the majority of the video footage of alpine skiers is captured during training, not racing. A large number of analyzed races with high reliability could therefore facilitate to identify KPIs in alpine skiing. The purpose of this study was to use the standardized typical error to explore the possibility to use telecasting to analyze performance and skiing characteristics in world cup slalom races. Method Standard telecasting footage (25 fps) from four different WC-races (eight runs) was used for analyzing turn times for eleven skiers (nine males and two females). The footage was analyzed at three separate situations, by two different alpine World Cup coaches and one video analyst. Turn time was defined as boot passage of the gate and all video analyses were made in DartFish ProSuite 6. Typical error (TE) was calculated by; TE=σ_diff/√(N_obs ) The standardized typical error (STE) was calculated by; TE= TE/√(((n_1-1)^2 σ_1^2+(n_2-1)^2 σ_2^2 ) /((n_1+n_2-2))-TE^2 ) The index described by Hopkins [1] was used for evaluating the influence of the STE. Results The mean turn time for the male skiers was 0.83 ± 0.18 s, with a coefficient of variation of 22%. The mean turn time for the two female skiers was 0.85 ± 0.19 s and the coefficient of variation was 22%. The TE between the different analyses was 0.03 s and the STE was 0.14. The results provide a detailed analysis of gate-to-gate times for each skier. Discussion The TE value of 0.03 s is most likely due to the 25 fps telecasting footage, where each frame is 0.04 s. The analysts must therefore choose one frame if the point of interest is between two frames. Hence, TE will presumably decrease with increase framerate. As the STE < 0.2, the disagreement between the different analysts can be considered as trivial [1, 2]. We here show how the STE can be used to identify inter-analyst reliability of alpine skiing video analyses. Furthermore, the presented method provides a robust, cheap and effective method to objectively analyze skiing performance and identifying plausible key performance indicators in alpine skiing. References 1. Hopkins, W., Reliability from consecutive pairs of trials (Excel spreadsheet). A new view of statistics, 2000. 2. Liu, H., et al., Inter-operator reliability of live football match statistics from OPTA Sportsdata. International Journal of Performance Analysis in Sport, 2013. 13(3): p. 803-821.

  • 49.
    Swarén, Mikael
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Larsson, Oscar
    Ultimate Performance AB, Uppsala.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Using telecasting to identify turn times in alpine skiing2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Alpine skiing can be considered as a “closed sport” where each athlete is alone in the course without any external disturbing moments. However, each alpine race is unique therefore never identical. In addition, the condition of the course is constantly changing as each skier makes new tracks in the snow. Identifying key performance indicators (KPI) and other characteristics are therefore difficult. The most frequently used analysis method in alpine skiing is video footage. However, it is not always possible for coaches to cover a complete course as they can be several kilometers long as e.g. downhill skiing. The purpose of this study was thus to explore the possibility to use telecasting to analyze performance and skiing characteristics in world cup slalom races to identify possible KPI.

  • 50.
    Swarén, Mikael
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. KTH.
    Soehnlein, Quirin
    Holmberg, Martin
    Stöggl, Thomas
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Salzburg University, Department of Sport Science and Kinesiology.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Using 3D motion capture to analyze ice-hockey shooting technique on ice2015Konferansepaper (Fagfellevurdert)
12 1 - 50 of 52
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf