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  • 1.
    Ainegren, Mats
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Laaksonen, Marko S.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    The influence of grip on oxygen consumption and leg forces when using classical style roller skis2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 2, p. 301-310Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the influence of classical style roller skis' grip (static friction coefficients, μ S) on cross-country skiers' oxygen consumption and leg forces during treadmill roller skiing, when using the diagonal stride and kick double poling techniques. The study used ratcheted wheel roller skis from the open market and a uniquely designed roller ski with an adjustable camber and grip function. The results showed significantly (P≤0.05) higher oxygen consumption (∼14%), heart rate (∼7%), and lower propulsive forces from the legs during submaximal exercise and a shorter time to exhaustion (∼30%) in incremental maximal tests when using roller skis with a μ S similar to on-snow skiing, while there was no difference between tests when using different pairs of roller skis with a similar, higher μ S. Thus, we concluded that oxygen consumption (skiing economy), propulsive leg forces, and performance time are highly changed for the worse when using roller skis with a lower μ S, such as for on-snow skiing with grip-waxed cross-country skis, in comparison to ratcheted wheel roller skis with several times higher μ S.

  • 2.
    Andersson, Erik
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Björklund, Glenn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Swedish Olympic Committee, Stockholm, Sweden.
    Ørtenblad, Niels
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. 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 skiing2017In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 27, no 4, p. 385-398Article in journal (Refereed)
    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.

  • 3.
    Andersson, Erik
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Stöggl, Thomas
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Pellegrini, Barbara
    CeRiSM Research Center for Sport, Mountain and Health University of Verona Rovereto Italy.
    Sandbakk, Øyvind
    Department of Human Movement Science Norwegian University of Science and Technology Trondheim Norway.
    Ettema, Gertjan
    Department of Human Movement Science Norwegian University of Science and Technology Trondheim Norway.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Biomechanical analysis of the herringbone technique as employed by elite cross-country skiers2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 3, p. 542-552Article in journal (Refereed)
    Abstract [en]

    This investigation was designed to analyse the kinematics and kinetics of cross-country skiing at different velocities with the herringbone technique on a steep incline. Eleven elite male cross-country skiers performed this technique at maximal, high, and moderate velocities on a snow-covered 15° incline. They positioned their skis laterally (25 to 30°) with a slight inside tilt and planted their poles laterally (8 to 12°) with most leg thrust force exerted on the inside forefoot. Although 77% of the total propulsive force was generated by the legs, the ratio between propulsive and total force was approximately fourfold higher for the poles. The cycle rate increased with velocity (1.20 to 1.60 Hz), whereas the cycle length increased from moderate up to high velocity, but then remained the same at maximal velocity (2.0 to 2.3 m). In conclusion, with the herringbone technique, the skis were angled laterally without gliding, with the forces distributed mainly on the inside forefoot to enable grip for propulsion. The skiers utilized high cycle rates with major propulsion by the legs, highlighting the importance of high peak and rapid generation of leg forces.

  • 4. Bucher Sandbakk, Silvana
    et al.
    Supej, Matej
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Department of Biomechanics, Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia.
    Sandbakk, Øyvind
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Department of Human Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Downhill turn techniques and associated physical characteristics in cross-country skiers2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 4, p. 708-716Article in journal (Refereed)
    Abstract [en]

    Three dominant techniques are used for downhill turning in cross-country skiing. In this study, kinematic, kinetic, and temporal characteristics of these techniques are described and related to skier strength and power. Twelve elite female cross-country skiers performed six consecutive turns of standardized geometry while being monitored by a Global Navigation Satellite System. Overall time was used as an indicator of performance. Skiing and turning parameters were determined from skier trajectories; the proportional use of each technique was determined from video analysis. Leg strength and power were determined by isometric squats and countermovement jumps on a force plate. Snow plowing, parallel skidding, and step turning were utilized for all turns. Faster skiers employed less snow plowing and more step turning, more rapid deceleration and earlier initiation of step turning at higher speed (r = 0.80–0.93; all P < 0.01). Better performance was significantly correlated to higher mean speed and shorter trajectory (r

    = 0.99/0.65; both P < 0.05) and to countermovement jump characteristics of peak force, time to peak force, and rate of force development (r  = -0.71/0.78/-0.83; all P < 0.05). In conclusion, faster skiers used step turning to a greater extent and exhibited higher maximal leg power, which enabled them to combine high speeds with shorter trajectories during turns.

  • 5.
    Calbet, J. A. L.
    et al.
    Univ Las Palmas Gran Canaria, Dept Phys Educ, Las Palmas Gran Canaria 35017, Canary Islands, Spain.
    Ponce-Gonzalez, J. G.
    Univ Las Palmas Gran Canaria, Dept Phys Educ, Las Palmas Gran Canaria 35017, Canary Islands, Spain.
    Perez-Suarez, I.
    Univ Las Palmas Gran Canaria, Dept Phys Educ, Las Palmas Gran Canaria 35017, Canary Islands, Spain.
    de la Calle Herrero, J.
    Univ Las Palmas Gran Canaria, Dept Phys Educ, Las Palmas Gran Canaria 35017, Canary Islands, Spain.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    A time-efficient reduction of fat mass in 4 days with exercise and caloric restriction2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 2, p. 223-233Article in journal (Refereed)
    Abstract [en]

    To determine whether a fast reduction in fat mass can be achieved in 4 days by combining caloric restriction (CR: 3.2kcal/kg body weight per day) with exercise (8-h walking+45-min arm cranking per day) to induce an energy deficit of approximate to 5000kcal/day, 15 overweight men underwent five experimental phases: pretest, exercise+CR for 4 days (WCR), control diet+reduced exercise for 3 days (DIET), and follow-up 4 weeks (POST1) and 1 year later (POST2). During WCR, the diet consisted solely of whey protein (n=8) or sucrose (n=7) (0.8g/kg body weight per day). After WCR, DIET, POST1, and POST2, fat mass was reduced by a mean of 2.1, 2.8, 3.8, and 1.9kg (P<0.05), with two thirds of this loss from the trunk; and lean mass by 2.8, 1.0, 0.5, and 0.4kg, respectively. After WCR, serum glucose, insulin, homeostatic model assessment, total and low-density lipoprotein cholesterol and triglycerides were reduced, and free fatty acid and cortisol increased. Serum leptin was reduced by 64%, 50%, and 33% following WCR, DIET, and POST1, respectively (P<0.05). The effects were similar in both groups. In conclusion, a clinically relevant reduction in fat mass can be achieved in overweight men in just 4 days by combining prolonged exercise with CR.

  • 6.
    Elmer, Steven
    et al.
    Department of Exercise and Sport Science, The University of Utah, Salt Lake City, Utah, USA.
    Hahn, S.
    McAllister, P.
    Leong, C.
    Martin, J.
    Improvements in multi-joint leg function following chronic eccentric exercise2012In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 22, no 5, p. 653-661Article in journal (Refereed)
    Abstract [en]

    Previous authors have reported that chronic eccentric cycling facilitates greater changes in multi-joint leg function (hopping frequency, maximum jumping height) compared with concentric cycling. Our purpose was to evaluate changes in leg spring stiffness and maximum power following eccentric and concentric cycling training. Twelve individuals performed either eccentric (n=6) or concentric (n=6) cycling for 7 weeks (3 sessions/week) while training duration progressively increased. Participants performed trials of submaximal hopping, maximal counter movement jumps, and maximal concentric cycling to evaluate leg spring stiffness, maximum jumping power, and maximum concentric cycling power respectively, before and 1 week following training. Total work during training did not differ between eccentric and concentric cycling (126 ± 15–728 ± 91 kJ vs 125 ± 10–787 ± 76 kJ). Following training, eccentric cycling exhibited greater changes in kleg and jumping Pmax compared with CONcyc (10 ± 3% vs −2 ± 4% and 7 ± 2% vs −2 ± 3%, respectively, P=0.05). Alterations in CONcycPmax did not differ between ECCcyc (1035 ± 142 vs 1030 ± 133 W) and CONcyc (1072 ± 98 vs 1081 ± 85 W). These data demonstrate that eccentric cycling is an effective method for improving leg spring stiffness and maximum power during multi-joint tasks that include stretch-shortening cycles. Improvements in leg spring stiffness and maximum power would be beneficial for both aging and athletic populations.

  • 7.
    Engan, Harald
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering. Department of Human Movement Science, Faculty of Social Sciences and Technology Management, NTNU, Trondheim, Norway.
    Schagatay, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    Lodin-Sundström, Angelica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    Richardson, Matt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Sustainable Building Engineering.
    Beekvelt, Mireille
    Department of Human Movement Science, Faculty of Social Sciences and Technology Management, NTNU, Trondheim, Norway.
    Effects of two weeks of daily apnea training on diving response, spleen contraction, and erythropoiesis in novel subjects.2013In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 3, p. 340-348Article in journal (Refereed)
    Abstract [en]

    Three potentially protective responses to hypoxia have been reported to be enhanced in divers: (1) the diving response, (2) the blood-boosting spleen contraction, and (3) a long-term enhancement of hemoglobin concentration (Hb). Longitudinal studies, however, have been lacking except concerning the diving response. Ten untrained subjects followed a 2-week training program with 10 maximal effort apneas per day, with pre- and posttraining measurements during three maximal duration apneas, and an additional post-training series when the apneic duration was kept identical to that before training. Cardiorespiratory parameters and venous blood samples were collected across tests, and spleen diameters were measured via ultrasound imaging. Maximal apneic duration increased by 44 s (P < 0.05). Diving bradycardia developed 3 s earlier and was more pronounced after training (P < 0.05). Spleen contraction during apneas was similar during all tests. The arterial hemoglobin desaturation (SaO(2)) nadir after apnea was 84% pretraining and 89% after the duration-mimicked apneas post-training (P < 0.05), while it was 72% (P < 0.05) after maximal apneas post-training. Baseline Hb remained unchanged after training, but reticulocyte count increased by 15% (P < 0.05). We concluded that the attenuated SaO(2) decrease during mimic apneas was due mainly to the earlier and more pronounced diving bradycardia, as no enhancement of spleen contraction or Hb had occurred. Increased reticulocyte count suggests augmented erythropoiesis.

  • 8.
    Gejl, K. D.
    et al.
    Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Campusvej 55, DK-5230 Odense M, Denmark.
    Hvid, L. G.
    Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Campusvej 55, DK-5230 Odense M, Denmark.
    Willis, Sarah J.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Andersson, Erik
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Swedish Olympic Comm, Stockholm, Sweden.
    Jensen, R.
    Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Campusvej 55, DK-5230 Odense M, Denmark.
    Frandsen, U.
    Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Campusvej 55, DK-5230 Odense M, Denmark.
    Hansen, J.
    Rigshosp, Ctr Inflammat & Metab, Dept Infect Dis, DK-2100 Copenhagen, Denmark.
    Plomgaard, P.
    Rigshosp, Ctr Inflammat & Metab, Dept Infect Dis, DK-2100 Copenhagen, Denmark.
    Ortenblad, N.
    Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Campusvej 55, DK-5230 Odense M, Denmark.
    Repeated high-intensity exercise modulates Ca2+ sensitivity of human skeletal muscle fibers2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 5, p. 488-497Article in journal (Refereed)
    Abstract [en]

    The effects of short-term high-intensity exercise on single fiber contractile function in humans are unknown. Therefore, the purposes of this study were: (a) to access the acute effects of repeated high-intensity exercise on human single muscle fiber contractile function; and (b) to examine whether contractile function was affected by alterations in the redox balance. Eleven elite cross-country skiers performed four maximal bouts of 1300m treadmill skiing with 45min recovery. Contractile function of chemically skinned single fibers from triceps brachii was examined before the first and following the fourth sprint with respect to Ca2+ sensitivity and maximal Ca2+-activated force. To investigate the oxidative effects of exercise on single fiber contractile function, a subset of fibers was incubated with dithiothreitol (DTT) before analysis. Ca2+ sensitivity was enhanced by exercise in both MHC I (17%, P<0.05) and MHC II (15%, P<0.05) fibers. This potentiation was not present after incubation of fibers with DTT. Specific force of both MHC I and MHC II fibers was unaffected by exercise. In conclusion, repeated high-intensity exercise increased Ca2+ sensitivity in both MHC I and MHC II fibers. This effect was not observed in a reducing environment indicative of an exercise-induced oxidation of the human contractile apparatus.

  • 9.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The elite cross-country skier provides unique insights into human exercise physiology2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no S4, p. 100-109Article, review/survey (Refereed)
    Abstract [en]

    Successful cross-country skiing, one of the most demanding of endurance sports, involves considerable physiological challenges posed by the combined upper- and lower-body effort of varying intensity and duration, on hilly terrain, often at moderate altitude and in a cold environment. Over the years, this unique sport has helped physiologists gain novel insights into the limits of human performance and regulatory capacity. There is a long-standing tradition of researchers in this field working together with coaches and athletes to improve training routines, monitor progress, and refine skiing techniques. This review summarizes research on elite cross-country skiers, with special emphasis on the studies initiated by Professor Bengt Saltin. He often employed exercise as a means to learn more about the human body, successfully engaging elite endurance athletes to improve our understanding of the demands, characteristics, and specific effects associated with different types of exercise.

  • 10.
    Holmberg, Hans-Christer
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Rosdahl, Hans
    Svedenhag, Jan
    Lung function and oxygen uptake during double poling, running and diagonal skiing in elite cross-country skiers2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 4, p. 437-444Article in journal (Refereed)
    Abstract [en]

    Arterial desaturation during exercise is common in endurance-trained athletes, a phenomenon often more pronounced when the muscle mass engaged in the exercise is large. With this background, the present study monitored seven international-level cross country skiers performing on a treadmill while running (RUN), double poling (DP; upper body exercise) and diagonal skiing (DIA; arm and leg exercise). Static and dynamic lung function tests were performed and oxygen uptake was measured during submaximal and maximal exercise. Lung function variables (including the diffusion capacity) were only 5-20% higher than reported in sedentary men. Vital capacity was considerably lower than expected from the skiers' maximal oxygen uptake (VO(2max)), but the maximal ventilation followed a linear relationship with VO(2max). None or only a mild desaturation was observed in DP, RUN and DIA. Blood lactate concentration was slightly higher in DIA than in DP but not different from RUN. In DIA, VO(2max) was 6.23 +/- 0.47 L/min (mean +/- SD), which was 3.8% and 13.9% higher than in RUN and DP, respectively, with similar peak heart rates for the three exercise modes. No relationships were present either between the degree of desaturation and pulmonary functions tests, or with peak oxygen uptakes. The low blood lactate accumulation during the exhaustive efforts contributed to the arterial oxygen saturation being mild in spite of the very high oxygen uptake observed in these skiers.

  • 11. Häkkinen, K
    et al.
    Komi, P.V
    Tesch, P.A
    Effect of combined concentric and eccentric strength training and detraining on force-time, muscle fiber and metabolic characteristics of leg extensor muscles1981In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 3, p. 50-58Article in journal (Refereed)
  • 12.
    Hébert-Losier, Kim
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Jensen, Kurt
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Mourot, Laurent
    Culture Sport Health Society and Exercise Performance Health Innovation Platform, Franche-Comté University, Besançon, France .
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, Sweden.
    The influence of surface on the running velocities of elite and amateur orienteer athletes2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 6, p. 448--455Article in journal (Refereed)
    Abstract [en]

    We compared the reduction in running velocities from road to off-road terrain in eight elite and eight amateur male orienteer athletes to investigate whether this factor differentiates elite from amateur athletes. On two separate days, each subject ran three 2-km time trials and three 20-m sprints "all-out" on a road, on a path, and in a forest. On a third day, the running economy and maximal aerobic power of individuals were assessed on a treadmill. The elite orienteer ran faster than the amateur on all three surfaces and at both distances, in line with their better running economy and aerobic power. In the forest, the elites ran at a slightly higher percentage of their 2-km (∼3%) and 20-m (∼4%) road velocities. Although these differences did not exhibit traditional statistical significance, magnitude-based inferences suggested likely meaningful differences, particularly during 20-m sprinting. Of course, cognitive, mental, and physical attributes other than the ability to run on different surfaces are required for excellence in orienteering (e.g., a high aerobic power). However, we suggest that athlete-specific assessment of running performance on various surfaces and distances might assist in tailoring training and identifying individual strengths and/or weaknesses in an orienteer.

  • 13.
    Ihalainen, Simo
    et al.
    KIHU - Research Institute for Olympic Sports, Jyväskylä, and Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
    Laaksonen, Marko
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Kuitunen, Sami
    KIHU – Research Institute for Olympic Sports, Jyväskylä, Finland.
    Leppävuori, Antti
    Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, and Finnish Biathlon Association, Finland.
    Mikkola, Jussi
    KIHU – Research Institute for Olympic Sports, Jyväskylä, Finland.
    Lindinger, Stefan
    Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria.
    Linnamo, Vesa
    Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
    Technical determinants of biathlon standing shooting performance before and after race simulation2018In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 28, no 6, p. 1700-1707Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to identify performance determining factors in biathlon standing shooting in rest and after intense exercise. Eight Finnish national and nine junior team biathletes participated in the study. Participants fired 40 resting shots (REST) and 2*5 competition simulation shots (LOAD) after 5 min of roller skiing at 95% of peak heart rate. Hit percentage, aiming point trajectory and postural balance were measured from each shot. Cleanness of triggering (ATV, movement of the aiming point 0-0.2 s before the shot) and vertical stability of hold (DevY) were the most important components affecting shooting performance both in REST (DevY, R=-0.61, p<0.01; ATV, R=-0.65, p<0.01) and in LOAD (DevY, R=-0.50, p<0.05; ATV, R=-0.77, p<0.001). Postural balance, especially in shooting direction, was related to DevY and ATV. Stability of hold in horizontal (F(1,15)=7.025, p<0.05) and vertical (F(1,15)=21.285, p<0.001) directions, aiming accuracy (F(1,15)=9.060, p<0.01), and cleanness of triggering (F(1,15)=59.584, p<0.001) decreased from REST to LOAD, accompanied by a decrease in postural balance. National and junior team biathletes differed only in hit percentage in REST (92±8 % vs. 81±8 %, p<0.05) and left leg postural balance in shooting direction in LOAD (0.31±0.18 mm vs. 0.52±0.20 mm, p<0.05), and the intense exercise affected the shooting technical components similarly in both national and junior groups. Biathletes should focus on cleanness of triggering and vertical stability of hold in order to improve biathlon standing shooting performance. More stable postural balance in shooting direction could help to improve these shooting technical components.

  • 14.
    Lussiana, T.
    et al.
    Research Unit EA4660, Culture Sport Health Society and Exercise Performance Health Innovation Platform, Franche-Comté University, Besançon, France .
    Fabre, Nicolas
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Hébert-Losier, Kim
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Mourot, L.
    Research Unit EA4660, Culture Sport Health Society and Exercise Performance Health Innovation Platform, Franche-Comté University, Besançon, France .
    Effect of slope and footwear on running economy and kinematics2013In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 4, p. e246-e253Article in journal (Refereed)
    Abstract [en]

    Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4 +/- 4.4 years; 177.5 +/- 5.2cm; 69.5 +/- 5.3kg) ran 14 5-min trials in a randomized sequence at 10km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from -8% to +8%. We found that Cr increased with slope gradient (P<0.01) and was on average 1.3% lower in MS than TS (P<0.01). However, slope did not influence the Cr difference between MS and TS. In MS, contact times were lower (P<0.01), flight times (P=0.01) and step frequencies (P=0.02) were greater at most slope gradients, and plantar-foot angles - and often ankle plantar-flexion (P=0.01) - were greater (P<0.01). The 1.3% difference between footwear identified here most likely stemmed from the difference in shoe mass considering that the Cr difference was independent of slope gradient and that the between-footwear kinematic alterations with slope provided limited explanations.

  • 15.
    Patrician, Alexander
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Schagatay, Erika
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Dietary nitrate enhances arterial oxygen saturation after dynamic apnea2017In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 27, no 6, p. 622-626Article in journal (Refereed)
    Abstract [en]

    Breath-hold divers train to minimize their oxygen consumption to improve their apneic performance. Dietary nitrate has been shown to reduce the oxygen cost in a variety of situations, and our aim was to study its effect on arterial oxygen saturation (SaO2) after dynamic apnea (DYN) performance. Fourteen healthy male apnea divers (aged 33 ± 11 years) received either 70 mL of concentrated nitrate-rich beetroot juice (BR) or placebo (PL) on different days. At 2.5 h after ingesting the juice, they were asked to perform 2 × 75 m DYN dives in a pool with 4.5-min recovery between dives. Each dive started after 2-min countdown and without any warm-up apneas, hyperventilation, or lung packing. SaO2 and heart rate were measured via pulse oximetry for 90 s before and after each dive. Mean SaO2 nadir values after the dives were 83.4 ± 10.8% with BR and 78.3 ± 11.0% with PL (P &lt; 0.05). At 20-s post-dive, mean SaO2 was 86.3 ± 10.6% with BR and 79.4 ± 10.2% with PL (P &lt; 0.05). In conclusion, BR juice was found to elevate SaO2 after 75-m DYN. These results suggest an oxygen conserving effect of dietary nitrate supplementation, which likely has a positive effect on maximal apnea performance.

  • 16.
    Poetzelsberger, B.
    et al.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Lindinger, S. J.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Stöggl, Thomas
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Buchecker, M.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Mueller, E.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Alpine Skiing With total knee ArthroPlasty (ASWAP): effects on gait asymmetries2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, p. 49-59Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to examine the effect of a 12-week recreational skiing intervention on functional gait performance in people with unilateral total knee arthroplasty (TKA). Twenty-three older adults (71 +/- 5 years) were assigned to the intervention (IG) or control group (CG). Test time and ground reaction forces (GRF) were recorded at pre- and post-intervention and in the retention phase during functional gait tests. Ground contact was recorded bilaterally and divided into the weight acceptance and push-off phases. In IG, a faster stair descent time (16%) was observed at post-test with no further change at the retention test. The asymmetry indices for all analyzed variables were decreased in stair descent and during weight acceptance in stair ascent and level walking without further changes between post- and retention test. The reduced asymmetries occurred mainly because of increased loading of the operated leg. Most variables were unchanged in CG. Similar to the force data, the asymmetry index for temporal stride characteristics was reduced in all stair descent variables. These results demonstrate that alpine skiing as a leisure-time activity has a beneficial effect on gait performance and leads to a more balanced load distribution between the legs during daily activities.

  • 17.
    Poetzelsberger, B.
    et al.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Stöggl, Thomas
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Lindinger, S. J.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Dirnberger, J.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Stadlmann, M.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Buchecker, M.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Hofstaedter, T.
    Paracelsus Med Univ Salzburg, Orthopaed Clin, Salzburg, Austria.
    Gordon, K.
    Paracelsus Med Univ Salzburg, Orthopaed Clin, Salzburg, Austria.
    Mueller, E.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Alpine Skiing With total knee ArthroPlasty (ASWAP): effects on strength and cardiorespiratory fitness2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, p. 16-25Article in journal (Refereed)
    Abstract [en]

    This study investigated the effect of a 12-week recreational skiing intervention on lower limb muscle strength and cardiorespiratory fitness in participants with unilateral total knee arthroplasty (TKA). Twenty-seven older adults (70 +/- 5 years) were assigned to the intervention (n=13) or control group (n=14) after surgery (2.5 +/- 1 years). Leg muscle strength was measured using an IsoMed 2000 dynamometer and cardiorespiratory fitness was determined by cycle ergometry before and after the intervention as well as after an 8-week retention period. The skiing intervention led to increased muscle strength in the operated leg during unilateral single joint isometric extension (maximal force: 11%; P<0.05; rate of torque development: 24%; P<0.05) and during the unilateral multi-joint isokinetic single leg strength test (8%; P<0.05). This resulted in a decreased asymmetry index in the isokinetic test (13% to 5%; P<0.05). These adaptations remained unchanged toward the retention test. No effect was observed for cardiorespiratory fitness. The results demonstrate that muscle contraction forces required during recreational skiing in individuals with TKA seem adequate and effective to increase quadriceps and hamstrings muscle strength in the initially weaker operated leg and to reduce an augmented post-operative asymmetry index.

  • 18.
    Poetzelsberger, B.
    et al.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Stöggl, Thomas
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Scheiber, P.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Lindinger, S. J.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Seifert, J.
    Montana State Univ, Movement Sci Lab, Bozeman, MT 59717 USA.
    Fink, C.
    Sportsclin Austria, Innsbruck, Austria.
    Mueller, E.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5400 Salzburg, Austria.
    Alpine Skiing With total knee ArthroPlasty (ASWAP): symmetric loading during skiing2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no S1, p. 60-66Article in journal (Refereed)
    Abstract [en]

    The aim of this pilot study was to determine the pressure distribution, symmetry of load between operated (OP) and non-operated (NOP) leg, and pain level during alpine skiing in participants with unilateral total knee arthroplasty (TKA). The responses of the dependent variables were analyzed following a 10-week guided skiing intervention of 2-3 days of skiing per week. Ground reaction force (GRF) was recorded bilaterally and was determined for 13 participants with TKA (65 +/- 4 years) at pre- and post-test. Additionally, pain perception was determined using a numeric rating scale in the OP leg at both test sessions and after each skiing day. No statistical differences were observed between OP and NOP legs for peak and average GRF as well as the asymmetry indices at pre-test. Pain perception was low and was not increased as a consequence of the skiing intervention. In conclusion, alpine skiing did not lead to increased or decreased loading of the OP leg compared with the NOP leg. Therefore, alpine skiing may be allowed for patients with skiing experience and a good clinical outcome.

  • 19.
    Sandbakk, Öyvind
    et al.
    Norwegian Univ Sci & Technol, Dept Human Movement Sci, N-7491 Trondheim, Norway.
    Ettemaa, Gertjan
    Norwegian Univ Sci & Technol, Dept Human Movement Sci, N-7491 Trondheim, Norway.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Gender differences in endurance performance by elite cross-country skiers are influenced by the contribution from poling2014In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, no 1, p. 28-33Article in journal (Refereed)
    Abstract [en]

    Greater gender differences have been found in exercise modes where the upper body is involved. Therefore, the present study investigated the influence of poling on gender differences in endurance performance by elite cross-country skiers. Initially, the performance of eight male and eight female sprint skiers was compared during four different types of exercise involving different degrees of poling: double poling (DP), G3 skating, and diagonal stride (DIA) techniques during treadmill roller skiing, and treadmill running (RUN). Thereafter, DP was examined for physiological and kinematic parameters. The relative gender differences associated with the DP, G3, DIA and RUN performances were approximately 20%, 17%, 14%, and 12%, respectively. Thus, the type of exercise exerted an overall effect on the relative gender differences (P < 0.05). In connection with DP, the men achieved 63%, 16%, and 8% higher VO2peak than the women in absolute terms and with normalization for total and fat-free body mass (all P < 0.05). The DP VO2peak in percentage of VO2max in RUN was higher in men (P < 0.05). The gender difference in DP peak cycle length was 23% (P < 0.05). In conclusion, the present investigation demonstrates that the gender difference in performance by elite sprint skiers is enhanced when the contribution from poling increases.

  • 20.
    Sandbakk, Øyvind
    et al.
    Human Movement Science Programme, Norwegian University of Science and Technology, Trondheim, Norway.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Leirdal, Stig
    Human Movement Science Programme, Norwegian University of Science and Technology, Trondheim, Norway.
    Ettema, Gertjan
    Human Movement Science Programme, Norwegian University of Science and Technology, Trondheim, Norway.
    The Physiology of World Class Sprint Skiers2011In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 21, no 6, p. e9-e16Article in journal (Refereed)
    Abstract [en]

    The present study investigated the physiological characteristics of eight world class (WC) and eight national class (NC) Norwegian sprint cross-country skiers. To measure physiological response and treadmill performance, the skiers performed a submaximal test, a peak aerobic capacity (VO2peak) test, and a peak treadmill speed (Vpeak) test in the skating G3 technique. Moreover, the skiers were tested for G3 acceleration outdoors on asphalt and maximal strength in the lab. The standard of sprint skating performance level on snow was determined by FIS points, and the training distribution was quantified. WC skiers showed 8%higher VO2peak and twice as long VO2 plateau time at the VO2peak test, and higher gross efficiency (GE) at the submaximal test (all P < 0.05). Furthermore, WC skiers showed 8%higher Vpeak (P < 0.05), but did not differ from NC skiers in acceleration and maximal strength. WC skiers performed more low and moderate-intensity endurance training and speed training (both P < 0.05). The current results indicate that aerobic capacity, efficiency and high speed capacity differentiate WC and NC sprint skiers and are strong determinants of sprint performance.

  • 21.
    Sperlich, B.
    et al.
    Integrative and Experimental Training Science, Institute for Sport Sciences, Julius-Maximilians University Würzburg, Würzburg, Germany.
    Calbet, J. A. L.
    Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain; School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
    Boushel, R.
    School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. School of Kinesiology, University of British Columbia, Vancouver, BC, Canada; School of Sport Sciences, University of Tromsø – The Arctic University of Norway, Tromsø, Norway.
    Is the use of hyperoxia in sports effective, safe and ethical?2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 11, p. 1268-1272Article in journal (Refereed)
  • 22.
    Sperlich, B.
    et al.
    Institute of Training Science and Sport Informatics, German Sport University, Am Sportpark Müngersdorf, Köln, Germany.
    Zinner, C.
    German Research Centre of Elite Sport, Am Sportpark Müngersdorf, Köln, Germany.
    Krueger, M.
    German Research Centre of Elite Sport, Am Sportpark Müngersdorf, Köln, Germany.
    Wegrzyk, J.
    German Research Centre of Elite Sport, Am Sportpark Müngersdorf, Köln, Germany.
    Mester, J.
    German Research Centre of Elite Sport, Am Sportpark Müngersdorf, Köln, Germany.
    Holmberg, H. -C
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Ergogenic effect of hyperoxic recovery in elite swimmers performing high-intensity intervals2011In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 21, no 6, p. e421-e429Article in journal (Refereed)
    Abstract [en]

    This investigation tested the hypothesis that breathing oxygen-enriched air (FiO2=1.00) during recovery enhances peak (Ppeak) and mean power (Pmean) output during repeated high-intensity exercise. Twelve elite male swimmers (21 ± 3 years, 192.1 ± 5.9cm, 79.1 ± 8.2kg) inhaled either hyperoxic (HOX) or normoxic (NOX) air during 6-min recovery periods between five repetitions of high-intensity bench swimming, each involving 40 maximal armstrokes. Oxygen partial pressure (pO2) and saturation (SO2), [H+], pH, base excess and blood lactate concentration were measured before and after all intervals. The production of the reactive oxygen species (ROS) hydrogen peroxide was measured before, directly after and 15min after the test. Ppeak and Pmean with HOX recovery were significantly higher than with NOX throughout the third, fourth and fifth intervals (P<0.001-0.04). With HOX, electromyography activity was lower during the third, fourth and fifth intervals than during the first (P=0.05-0.001), with no such changes in NOX (P=0.99). There were no differences in blood lactate, pH, [H+] or base excess and ROS production at any time point with either HOX or NOX recovery. These findings demonstrate that the Ppeak and Pmean of elite swimmers performing high-intensity intervals can be improved by exposure to oxygen-enriched air during recovery. © 2011 John Wiley & Sons A/S.

  • 23.
    Stocks, Ben
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Human Physiology Research Group Department for Health University of Bath, Bath, UK.
    Betts, James
    Human Physiology Research Group Department for Health University of Bath, Bath, UK.
    McGawley, Kerry
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Effects of carbohydrate dose and frequency on metabolism, gastrointestinal discomfort, and cross-countryskiing performance2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 9, p. 1100-1108Article in journal (Refereed)
    Abstract [en]

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

  • 24.
    Stöggl, R.
    et al.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5020 Salzburg, Austria.
    Mueller, E.
    Salzburg Univ, Dept Sport Sci & Kinesiol, A-5020 Salzburg, Austria.
    Stöggl, Thomas
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Salzburg Univ, Dept Sport Sci & Kinesiol, A-5020 Salzburg, Austria.
    Motor abilities and anthropometrics in youth cross-country skiing2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 1, p. E70-E81Article in journal (Refereed)
    Abstract [en]

    The purposes were to validate whether general motor abilities and anthropometrics are determinants of youth cross-country (XC) skiing performance; evaluate gender-specific differences; and to establish noninvasive diagnostics. Fifty-one youth XC skiers (34 boys; 13.8 +/- 0.6 years and 17 girls; 13.4 +/- 0.9 years) performed motor skill and laboratory tests, and anthropometric data were collected and correlated with XC skiing performance. Anthropometrics and maturity status were related to boys but not to girls XC skiing performance. Push-ups and 20-m sprint were correlated to XC skiing performance in both boys and girls. XC skiing performance of boys was predominantly influenced by upper body and trunk strength capacities (medicine ball throw, push-ups, and pull-ups) and jumping power (standing long and triple jump), whereas XC skiing of girls was mainly influenced by aerobic capacities (3000-m run). Laboratory measures did not reveal greater correlations to XC skiing performance compared with simple test concepts of speed, strength, and endurance. Maturity was a major confounding variable in boys but not girls. Use of noninvasive simple test concepts for determination of upper body strength, speed, and endurance represent practicable support for ski clubs, schools, or skiing federations in the guidance and evaluation of young talent, being aware of the effect of maturity especially in boys.

  • 25.
    Stöggl, T.
    et al.
    Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria.
    Holmberg, H. -C
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Force interaction and 3D pole movement in double poling2011In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 21, no 6, p. e393-e404Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to analyze double poling using combined kinetic and 3D kinematic analysis at high skiing speeds as regards pole force components, pole angles and pole behavior during the poling and swing phase. The hypothesis was that a horizontal pole force is more predictive for maximal skiing speed (Vmax) than the resultant pole force. Sixteen elite skiers performed a double-poling Vmax test while treadmill roller skiing. Pole forces and 3D kinematics of pole movement at a speed of 30km/h were analyzed and related to Vmax. The duration of the "preparation phase" showed the strongest relationship with Vmax (r=0.87, P<0.001). Faster skiers generated longer cycle lengths with longer swing and poling times, had less inclined pole angles at pole plant and a later peak pole force. Horizontal pole forces were not more highly related to Vmax compared with the resultant pole force. Impact force was not related to Vmax. At high skiing speeds, skiers should aim to combine high pole forces with appropriate timing of pole forces and appropriate pole and body positions during the swing and poling phase. The emphasis in training should be on the development of specific strength capacities for pole force production and the utilization of these capacities in double-poling training sessions. © 2011 John Wiley & Sons A/S.

  • 26.
    Stöggl, Thomas
    et al.
    Department of Sport Science and Kinesiology, University of Salzburg, Austria.
    Björklund, Glenn
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Biomechanical determinants of oxygen extraction during cross-country skiing2013In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 1, p. e9-e20Article in journal (Refereed)
    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.

  • 27.
    Stöggl, Thomas
    et al.
    Department of Sport Science and Kinesiology, University of Salzburg & Christian Doppler Laboratory, Salzburg, Austria.
    Mueller, Erich
    Department of Sport Science and Kinesiology, University of Salzburg & Christian Doppler Laboratory, Salzburg, Austria.
    Ainegren, Mats
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Ainegren, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    General strength and kinetics: fundamental to sprinting faster in cross country skiing?2011In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 21, no 6, p. 791-803Article in journal (Refereed)
    Abstract [en]

    To determine relationships between general strength, maximal skiing speed (16 male elite skiers underwent three double poling, diagonal stride and V2 on a treadmill. The analyzed skiing speeds and leg and arm kinetics were among the highest ever recorded. Relationships between general strength exercises and Power output in bench press and bench pull were related to maximum was related to V2. Isometric squats were not associated with height and rate of force development during squat jump Vmax), pole and leg kinetics and kinematics,Vmax tests inVmax were technique dependent.Vmax in DP and diagonal stride, whereas each 1 repetitionVmax in all three techniques, whereas jump were. Analysis of kinetics and kinematics revealed that it was not exclusively the magnitude of applied forces during skiing, but the timing and proper instant of force application were major factors discriminating between faster and slower skiers. For all techniques, the faster skiers used different skiing strategies when approaching with the slower skiers. General strength and power Vmax when compared per se  seem not to be major determinants of performance in elite skiers, whereas coordination of these capacities within the different and complex skiing movements seems to be the discriminating factor.

  • 28.
    Supej, Matej
    et al.
    Department of Biomechanics, Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia .
    Kipp, Ronald W.
    Exercise and Sport Science, University of Utah, Salt Lake City, USA .
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Mechanical parameters as predictors of performance in alpine World Cup slalom racing2011In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 21, no 6, p. e72-e81Article in journal (Refereed)
    Abstract [en]

    The aims of the present study were to develop a method for classifying slalom skiing performance and to examine differences in mechanical parameters. Eighteen elite skiers were recorded with 3-D kinematical measurements and thereafter divided into a higher (HP) and lower performance (LP) group, using the ratio between the difference in mechanical energy divided by the mass of the skier and section entrance velocity (Δemech/vin). Moreover, the skiers’ velocity (v), acceleration (a), centre of mass turn radii (RCM) and skis’ turn radii (RAMS), ground reaction forces (GRF) and differential specific mechanical energy (diff(emech)) were calculated. v and diff(emech) were different between the performance groups (P < 0.001 and P < 0.05), while no inter-group differences in RCM, RAMS, a and GRF were observed. A relationship between RAMS and diff(emech) was demonstrated (r = 0.58; P < 0.001). The highest GRFs were related to the lowest diff(emech) and a was related to GRF (r = -0.60; P < 0.001). The Δemech/vin predicted performance over short course sections. The HP skiers skied with a higher v and a similar range of diff(emech). We suggest that shortest RAMS and the highest GRFs should be reduced in elite slalom in order to increase performance.

  • 29. Supej, Matej
    et al.
    Sætran, Lars
    Department of Energy and Process Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
    Oggiano, L
    Department of Energy and Process Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
    Ettemaa, Gertjan
    Department of Human Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
    Šarabon, N
    Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Koper, Slovenia.
    Nemec, B
    Department of Biocybernetics, Automatics and Robotics, Josef Stefan Institute, Ljubljana, Slovenia.
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Aerodynamic drag is not the major determinant of performance during giant slalom skiing at the elite level2013In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 1, p. e38-e47Article in journal (Refereed)
    Abstract [en]

    This investigation was designed to (a) develop an individualized mechanical model for measuring aerodynamic drag (Fd) while ski racing through multiple gates, (b) estimate energy dissipation (Ed) caused by Fd and compare this to the total energy loss (Et), and (c) investigate the relative contribution of Ed/Et to performance during giant slalom skiing (GS). Nine elite skiers were monitored in different positions and with different wind velocities in a wind tunnel, as well as during GS and straight downhill skiing employing a Global Navigation Satellite System. On the basis of the wind tunnel measurements, a linear regression model of drag coefficient multiplied by cross-sectional area as a function of shoulder height was established for each skier (r > 0.94, all P < 0.001). Skiing velocity, Fd, Et, and Ed per GS turn were 15–21 m/s, 20–60 N, −11 to −5 kJ, and −2.3 to −0.5 kJ, respectively. Ed/Et ranged from ∼5% to 28% and the relationship between Et/vin and Ed was r = −0.12 (all NS). In conclusion, (a) Fd during alpine skiing was calculated by mechanical modeling, (b) Ed made a relatively small contribution to Et, and (c) higher relative Ed was correlated to better performance in elite GS skiers, suggesting that reducing ski–snow friction can improve this performance.

  • 30. Terzis, Gerasimos
    et al.
    Stattin, B
    Holmberg, Hans-Christer
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Upper body training and the triceps brachii muscle of elite cross country skiers2006In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 16, no 2, p. 121-126Article in journal (Refereed)
    Abstract [en]

    This study aimed at evaluating whether addition of extensive upper body training in well-trained cross country skiers induces an adaptation of the triceps brachii (TB) muscle and whether this affects performance. Muscle biopsies were obtained from TB muscle in six male elite cross country skiers before and after 20 weeks of increased upper body training. The cross-sectional area of type I and IIA fibers increased by 11.3% and 24.0%, respectively, and so did the number of capillaries per fiber (2.3�3.2) (all P<0.05). SDS-polyacrylamide electrophoresis revealed in single fibers that the number of fibers expressing myosin heavy chain (MHC) type I isoform decreased from 68.7% to 60.9% (P<0.05), MHC I/IIA isoform was unaltered, while MHC IIA fibers increased from 21.6% to 35.7% and the 4.8% MHC IIA/IIX disappeared with the training (both P<0.05). Citrate synthase and 3-hydroxyacyl coenzyme A dehydrogenase activities increased by 23.3% and 15.4%, respectively, and double poling 10 km time-trial by 10.4% (all P<0.05). The values for TB are similar to what has been demonstrated for leg muscles after exercise training. The subjects who demonstrated the largest improvement in performance exhibited the largest muscle adaptation, which, in turn, was related to the pre-maximal oxygen uptake.

  • 31. Tesch, P
    et al.
    Larsson, L
    Eriksson, A
    Karlsson, J
    Muscle glycogen depletion and lactate concentration during down-hill skiing.1978In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 10, no 2, p. 85-90Article in journal (Refereed)
  • 32. Tesch, Per
    et al.
    Piehl, G
    Wilson, G
    Karlsson, J
    Physiological investigations of Swedish elite canoe competitors1976In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838Article in journal (Refereed)
  • 33. Thorstensson, A
    et al.
    Larsson, L
    Tesch, P
    Karlsson, J
    Muscle strength and fiber composition in athletes and sedentary men.1977In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 9, no 1, p. 26-30Article in journal (Refereed)
  • 34.
    Wedin, J. O.
    et al.
    Sundsvall Cty Hosp, Dept Clin Chem, SE-85186 Sundsvall, Sweden.
    Henriksson, Anders E.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Sundsvall Cty Hosp, Dept Clin Chem, SE-85186 Sundsvall, Sweden.
    Postgame elevation of cardiac markers among elite floorball players2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 4, p. 495-500Article in journal (Refereed)
    Abstract [en]

    Cardiac biomarker release after exercise is well documented in endurance sports, but neither the impact of intermittent high-intensity exercise nor the reproducibility has yet been established. Floorball, a popular sport in Scandinavia, involves intermittent periods of high-intensity exercise. This study aimed to determine the prevalence and reproducibility of elevated cardiac marker levels among elite floorball players after two games. Twenty-three healthy male elite floorball players of median age 19 years (range 16-34 years) participated in two standard games. Blood was drawn at three time points: pregame, immediately after, and 2h after the game. Creatine kinase MB (CK-MB), myoglobin, and high-sensitivity cardiac troponin T (hs-cTnT) were measured. The results showed significantly elevated median postgame values in all markers. In both games, hs-cTnT exceeded the cutoff for myocardial damage (14ng/L) 2h postgame in the same six players. The major findings were that postgame cardiac hs-cTnT values among elite floorball players were significantly elevated and reproducible. The findings imply that extended investigations should incorporate evaluation of myocardial function and myocardial perfusion during exercise to seek the clinical significance and underlying mechanisms of elevated cardiac troponin after high-intensity exercise.

  • 35.
    Örtenblad, Niels
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, DK-5230 Odense, Denmark.;Mid Sweden Univ, Dept Hlth Sci, Swedish Winter Sports Res Ctr, Ostersund, Sweden..
    Nielsen, J.
    Univ Southern Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, DK-5230 Odense, Denmark..
    Muscle glycogen and cell function - Location, location, location2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, p. 34-40Article, review/survey (Refereed)
    Abstract [en]

    The importance of glycogen, as a fuel during exercise, is a fundamental concept in exercise physiology. The use of electron microscopy has revealed that glycogen is not evenly distributed in skeletal muscle fibers, but rather localized in distinct pools. In this review, we present the available evidence regarding the subcellular localization of glycogen in skeletal muscle and discuss this from the perspective of skeletal muscle fiber function. The distribution of glycogen in the defined pools within the skeletal muscle varies depending on exercise intensity, fiber phenotype, training status, and immobilization. Furthermore, these defined pools may serve specific functions in the cell. Specifically, reduced levels of these pools of glycogen are associated with reduced SR Ca2+ release, muscle relaxation rate, and membrane excitability. Collectively, the available literature strongly demonstrates that the subcellular localization of glycogen has to be considered to fully understand the role of glycogen metabolism and signaling in skeletal muscle function. Here, we propose that the effect of low muscle glycogen on excitation-contraction coupling may serve as a built-in mechanism, which links the energetic state of the muscle fiber to energy utilization.

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