This study examined the influence of turn radius on velocity and energy profiles when skidding and step turning during more and less effective downhill turns while cross-country skiing. Thirteen elite female cross-country skiers performed single turns with a 9- or 12-m radius using the skidding technique and a 12- or 15-m radius with step turning. Mechanical parameters were monitored using a real-time kinematic Global Navigation Satellite System and video analysis. Step turning was more effective during all phases of a turn, leading to higher velocities than skidding (P < .05). With both techniques, a greater radius was associated with higher velocity (P < .05), but the quality of turning, as assessed on the basis of energy characteristics, was the same. More effective skidding turns involved more pronounced deceleration early in the turn and maintenance of higher velocity thereafter, while more effective step turning involved lower energy dissipation during the latter half of the turn. In conclusion, the single-turn analysis employed here reveals differences in the various techniques chosen by elite cross-country skiers when executing downhill turns of varying radii and can be used to assess the quality of such turns.
Øyvind Sandbakk, Silvana Bucher Sandbakk, Matej Supej, and Hans-Christer Holmberg
Billy Sperlich, Christoph Zinner, David Trenk, and Hans-Christer Holmberg
To examine whether a 3-min all-out test can be used to obtain accurate values for the maximal lactate steady state (v MLSS) and/or peak oxygen uptake (VO2peak) of well-trained runners.
The 15 male volunteers (25 ± 5 y, 181 ± 6 cm, 76 ± 7 kg, VO2peak 69.3 ± 9.5 mL · kg−1 · min−1) performed a ramp test, a 3-min all-out test, and several submaximal 30-min runs at constant paces of v END (mean velocity during the last 30 s of the 3-min all-out test) itself and v END +0.2, +0.1, –0.1, –0.2, –0.3, or –0.4 m/s.
v MLSS and v END were correlated (r = .69, P = .004), although v MLSS was lower (mean difference: 0.26 ± 0.32 m/s, 95% CI –.44 to –.08 m/s, P = .007, effect size = 0.65). The VO2peak values derived from the ramp and 3-min all-out tests were not correlated (r = .41, P = .12), with a mean difference of 523 ± 1002 mL (95% CI –31 to 1077 mL).
A 3-min all-out test does not provide a suitable measure of v MLSS or VO2peak for well-trained runners.
Billy Sperlich, Karsten Koehler, Hans-Christer Holmberg, Christoph Zinner, and Joachim Mester
The aim of the study was to determine the cardiorespiratory and metabolic characteristics during intense and moderate table tennis (TT) training, as well as during actual match play conditions.
Blood lactate concentration (Lac), heart rate (HR, beats per minute [bpm]), oxygen uptake (VO2), and energy expenditure (EE) in 7 male participants of the German junior national team (age: 14 ± 1 y, weight: 60.5 ± 5.6 kg height; 165 ± 8 cm) were examined during six training sessions (TS) and during an international match. The VO2 was measured continuously with portable gas analyzers. Lac was assessed every 1 to 3 min during short breaks.
Mean (peak) values for Lac, HR, VO2, and EE during the TS were 1.2 ± 0.7 (4.5) mmol·L–1, 135 ± 18 (184) bpm, 23.5 ± 7.3 (43.0) mL·kg–1· min–1, and 6.8 ± 2.0 (11.2) METs, respectively. During match play, mean (peak) values were 1.1 ± 0.2 (1.6) mmol·L–1, 126 ± 22 (189) bpm, 25.6 ± 10.1 (45.9) mL·kg–1·min–1, and 4.8 ± 1.4 (9.6) METs, respectively.
For the frst time, cardiorespiratory and metabolic data in elite junior table tennis have been documented demonstrating low cardiorespiratory and metabolic demands during TT training and match play in internationally competing juniors.
Laurent Mourot, Nicolas Fabre, Erik Andersson, Sarah Willis, Martin Buchheit, and Hans-Christer Holmberg
Postexercise heart-rate (HR) recovery (HRR) indices have been associated with running and cycling endurance-exercise performance. The current study was designed (1) to test whether such a relationship also exists in the case of cross-country skiing (XCS) and (2) to determine whether the magnitude of any such relationship is related to the intensity of exercise before obtaining HRR indices. Ten elite male cross-country skiers (mean ± SD; 28.2 ± 5.4 y, 181 ± 8 cm, 77.9 ± 9.4 kg, 69.5 ± 4.3 mL · min−1 · kg−1 maximal oxygen uptake [VO2max]) performed 2 sessions of roller-skiing on a treadmill: a 2 × 3-km time trial and the same 6-km at an imposed submaximal speed followed by a final 800-m time trial. VO2 and HR were monitored continuously, while HRR and blood lactate (BLa) were assessed during 2 min immediately after each 6-km and the 800-m time trial. The 6-km time-trial time was largely negatively correlated with VO2max and BLa. On the contrary, there was no clear correlation between the 800-m time-trial time and VO2, HR, or BLa. In addition, in no case was any clear correlation between any of the HRR indices and performance time or VO2max observed. These findings confirm that XCS performance is largely correlated with VO2max and the ability to tolerate high levels of BLa; however, postexercise HRR showed no clear association with performance. The homogeneity of the group of athletes involved and the contribution of the arms and upper body to the exercise preceding determination of HRR may explain this absence of a relationship.
Matthias W. Hoppe, Christian Baumgart, Jutta Bornefeld, Billy Sperlich, Jürgen Freiwald, and Hans-Christer Holmberg
The aims of this study were (1) to assess the running activities of adolescent tennis players during match play with respect to velocity, acceleration, and deceleration; (2) to characterize changes in these activities during the course of a match; and (3) to identify potential differences between winners and losers. Twenty well-trained adolescent male athletes (13 ± 1 y) played one simulated match each (giving a total of 10 matches), during which distances covered at different velocity categories (0 to < 1, 1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 m·s−1) and number of running activities involving high velocity (≥ 3 m·s−1), acceleration (≥ 2 m·s−2), and deceleration (≤ −2 m·s−2) were monitored using a global positioning system (10 Hz). Heart rate was also assessed. The total match time, total distance covered, peak velocity, and mean heart rate were 81.2 ± 14.6 min, 3362 ± 869 m, 4.4 ± 0.8 ms−1, and 159 ± 12 beats min−1, respectively. Running activities involving high acceleration (0.6 ± 0.2 n·min−1) or deceleration (0.6 ± 0.2 n·min−1) were three times as frequent as those involving high velocity (0.2 ± 0.1 n·min−1). No change in the pattern of running activities (P ≥ .13, d ≤ 0.39) and no differences between winners and losers (P ≥ .22, d ≤ 0.53) were evident during match play. We conclude that training of well-trained adolescent male tennis players need not focus on further development of their running abilities, since this physical component of multifactorial tennis performance does not change during the course of a match and does not differ between the winners and losers.
Billy Sperlich, Dennis-Peter Born, Christoph Zinner, Anna Hauser, and Hans-Christer Holmberg
To evaluate whether upper-body compression affects power output and selected metabolic, cardiorespiratory, hemodynamic, and perceptual responses during three 3-min sessions of double-poling (DP) sprint.
Ten well-trained male athletes (25 ± 4 y, 180 ± 4 cm, 74.6 ± 3.2 kg) performed such sprints on a DP ski ergometer with and without a long-sleeved compression garment.
Mean power output was not affected by such compression (216 ± 25 W in both cases; P = 1.00, effect size [ES] = 0.00), although blood lactate concentration was lowered (P < .05, ES = 0.50–1.02). Blood gases (ES = 0.07–0.50), oxygen uptake (ES = 0.04–0.28), production of carbon dioxide (ES = 0.01–0.46), heart rate (ES = 0.00–0.21), stroke volume (ES = 0.33–0.81), and cardiac output (ES = 0.20–0.91) were also all unaffected by upper-body compression (best P = 1.00). This was also the case for changes in the tissue saturation index (ES = 0.45–1.17) and total blood content of hemoglobin (ES = 0.09–0.85), as well as ratings of perceived exertion (ES = 0.15–0.88; best P = .96).
The authors conclude that the performance of well-trained athletes during 3 × 3-min DP sprints will not be enhanced by upper-body compression.
Dennis-Peter Born, Christoph Zinner, Britta Herlitz, Katharina Richter, Hans-Christer Holmberg, and Billy Sperlich
The current investigation assessed tissue oxygenation and local blood volume in both vastus lateralis muscles during 3000-m race simulations in elite speed skaters on ice and the effects of leg compression on physiological, perceptual, and performance measures.
Ten (6 female) elite ice speed skaters completed 2 on-ice trials with and without leg compression. Tissue oxygenation and local blood volume in both vastus lateralis muscles were assessed with near-infrared spectroscopy. Continuous measures of oxygen uptake, ventilation, heart rate, and velocity were conducted throughout the race simulations, as well as blood lactate concentration and ratings of perceived exertion before and after the trials. In addition, lap times were assessed.
The investigation of tissue oxygenation in both vastus lateralis muscles revealed an asymmetry (P < .00; effect size = 1.81) throughout the 3000-m race simulation. The application of leg compression did not affect oxygenation asymmetry (smallest P = .99; largest effect size = 0.31) or local blood volume (P = .33; 0.95). Lap times (P = .88; 0.43), velocity (P = .24; 0.84), oxygen uptake (P = .79; 0.10), ventilation (P = .11; 0.59), heart rate (P = .21; 0.89), blood lactate concentration (P = .82; 0.59), and ratings of perceived exertion (P = .19; 1.01) were also unaffected by the different types of clothing.
Elite ice speed skaters show an asymmetry in tissue oxygenation of both vastus lateralis muscles during 3000-m events remaining during the long gliding phases along the straight sections of the track. Based on the data, the authors conclude that there are no performance-enhancing benefits from wearing leg compression under a normal racing suit.
Billy Sperlich, Silvia Achtzehn, Mirijam Buhr, Christoph Zinner, Stefan Zelle, and Hans-Christer Holmberg
This study aimed to quantify the intensity profile of elite downhill mountain bike races during competitions.
Seventeen male downhill racers (22 ± 5 y; 185.1 ± 5.3 cm; 68.0 ± 3.9 kg; VO2peak: 59.4 ± 4.1 mL·min·kg−1) participated in the International German Downhill Championships in 2010. The racers’ peak oxygen uptake and heart rate (HR) at 2 and 4 mmol·L−1 blood lactate (HR2 and HR4), were assessed during an incremental laboratory step test (100 W, increase 40 W every 5 min). During the races, the HR was recorded and pre- and postrace blood lactate concentrations as well as salivary cortisol levels were obtained.
During the race, the absolute time spent in the “easy” intensity zone was 23.3 ± 6.8 s, 24.2 ± 12.8 s (HR2–HR4) in the “moderate” zone, and 151.6 ± 18.3 s (>HR4) in the “hard” zone. Eighty percent of the entire race was accomplished at intensities >90% HRpeak. Blood lactate concentrations postrace were higher than those obtained after the qualification heat (8.0 ± 2.5 mmol·L−1 vs 6.7 ± 1.8 mmol·L−1, P < .01). Salivary levels of cortisol before the competition and the qualification heat were twice as high as at resting state (P < .01).
This study shows that mountain bike downhill races are conducted at high heart rates and levels of blood lactate as well as increased concentration of salivary cortisol as marker for psycho-physiological stress.
Øyvind Sandbakk, David B. Pyne, Kerry McGawley, Carl Foster, Rune Kjøsen Talsnes, Guro Strøm Solli, Grégoire P. Millet, Stephen Seiler, Paul B. Laursen, Thomas Haugen, Espen Tønnessen, Randy Wilber, Teun van Erp, Trent Stellingwerff, Hans-Christer Holmberg, and Silvana Bucher Sandbakk
Background: Elite sport is continuously evolving. World records keep falling and athletes from a longer list of countries are involved. Purpose: This commentary was designed to provide insights into present and future trends associated with world-class endurance training based on the perspectives, experience, and knowledge of an expert panel of 25 applied sport scientists. Results: The key drivers of development observed in the past 10–15 years were related to (1) more accessible scientific knowledge for coaches and athletes combined with (2) better integration of practical and scientific exchange across multidisciplinary perspectives within professionalized elite athlete support structures, as well as (3) utilization of new technological advances. Based on these perspectives, we discerned and exemplified the main trends in the practice of endurance sports into the following categories: better understanding of sport-specific demands; improved competition execution; larger, more specific, and more precise training loads; improved training quality; and a more professional and healthier lifestyle. The main areas expected to drive future improvements were associated with more extensive use of advanced technology for monitoring and prescribing training and recovery, more precise use of environmental and nutritional interventions, better understanding of athlete–equipment interactions, and greater emphasis on preventing injuries and illnesses. Conclusions: These expert insights can serve as a platform and inspiration to develop new hypotheses and ideas, encourage future collaboration between researchers and sport practitioners, and, perhaps most important, stimulate curiosity and further collaborative studies about the training, physiology, and performance of endurance athletes.