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
Maria Heikkilä, Raisa Valve, Mikko Lehtovirta and Mikael Fogelholm
–20 years old. The three main sports among the participants were cross-country skiing ( n = 53 coaches and n = 111 athletes), orienteering ( n = 13 and n = 110), and biathlon ( n = 6 and n = 38). Other sports were endurance running and racewalking, triathlon, cycling, swimming, rowing, and canoeing
Nicolas Berryman, Iñigo Mujika and Laurent Bosquet
suggested that a CT mesocycle was associated with improvements (net standardized mean difference =0.52; 95% confidence interval, 0.33–0.70) in middle- and long-distance performance (events >75 s) in a variety of disciplines (running, cycling, cross-country skiing, and swimming). Interestingly, while VO 2
Christina Åsan Grasaas, Gertjan Ettema, Ann Magdalen Hegge, Knut Skovereng and Øyvind Sandbakk
This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.
Brent S. Rushall, Marty Hall, Laurent Roux, Jack Sasseville and Amy C. Rushall
The purpose of this investigation was to assess the effects of instructions—to think particular types of thoughts—on the cross-country skiing performances of elite skiers. Eighteen members of the Canadian Cross-Country Ski Team served as subjects. Instructions were given to plan and think particular types of thoughts while skiing, namely task-relevant statements, mood words, and positive self-statements. Performances on a standard test track under thought control conditions were compared to similar efforts under “normal” (control) thinking. Thirteen subjects also recorded heart rates at the completion of each trial. A balanced order design of two replications of each condition was employed in each of the three experiments. Sixteen subjects improved in all conditions whereas two subjects improved in only one condition. Heart rates were marginally higher and statistically significant in each experimental condition compared to the control condition. Performance improvements of more than 3% were registered under each thought content condition, even though all subjects reported that they were not aware of any effort differential. That performance improvements of this magnitude could be achieved in athletes of such a caliber indicates the value of attempts to use the particular forms of thoughts employed in this study for improving cross-country skiing performance.
Øyvind Skattebo, Thomas Losnegard and Hans Kristian Stadheim
Purpose: Long-distance cross-country skiers specialize to compete in races >50 km predominantly using double poling (DP). This emphasizes the need for highly developed upper-body endurance capacities and an efficient DP technique. The aim of this study was to investigate potential effects of specialization by comparing physiological capacities and kinematics in DP between long-distance skiers and skiers competing using both techniques (skating/classic) in several competition formats (“all-round skiers”). Methods: Seven male long-distance (32  y, 183  cm, 76  kg) and 6 all-round (25  y, 181  cm, 75  kg) skiers at high international levels conducted submaximal workloads and an incremental test to exhaustion for determination of peak oxygen uptake (VO2peak) and time to exhaustion (TTE) in DP and running. Results: In DP and running maximal tests, TTE showed no difference between groups. However, long-distance skiers had 5–6% lower VO2peak in running (81  vs 85  mL·kg−1·min−1; P = .07) and DP (73  vs 78  mL·kg−1·min−1; P < .01) than all-round skiers. In DP, long-distance skiers displayed lower submaximal O2 cost than all-round skiers (3.8 ± 3.6%; P < .05) without any major differences in cycle times or cyclic patterns of joint angles and center of mass. Lactate concentration over a wide range of speeds (45–85% of VO2peak) did not differ between groups, even though each workload corresponded to a slightly higher percentage of VO2peak for long-distance skiers (effect size: 0.30–0.68). Conclusions: The long-distance skiers displayed lower VO2peak but compensated with lower O2 cost to perform equally with the all-round skiers on a short TTE test in DP. Furthermore, similar submaximal lactate concentration and reduced O2 cost could be beneficial in sustaining high skiing speeds in long-duration competitions.
Kerry McGawley and Hans-Christer Holmberg
Cross-country-ski races place complex demands on athletes, with events lasting between approximately 3 min and 2 h. The aim of the current study was to compare the aerobic and anaerobic measures derived from a short time trial (TT) between male and female skiers using diagonal cross-country skiing.
Twenty-four highly trained cross-country skiers (12 male and 12 female, age 17.4 ± 1.4 y, body mass 68.2 ± 8.9 kg, height 174 ± 8 cm) participated. The submaximal VO2–speed relationship and VO2max were derived from an incremental ramp test to exhaustion (RAMP), while the accumulated oxygen deficit (AOD), peak VO2, and performance time were measured during a 600-m TT.
The female skiers took longer to complete the TT than the males (209 ± 9 s vs 166 ± 7 s, P < .001) and exhibited a lower relative anaerobic contribution (20% ± 4% vs 24% ± 3%, P = .015) and a higher fractional utilization of VO2max (84% ± 4% vs 79% ± 5%, P = .007) than males. Although there was no significant difference in AOD between the sexes (40.9 ± 9.5 and 47.3 ± 7.4 mL/kg for females and males, respectively; P = .079), the mean difference ± 90% confidence intervals of 6.4 ± 6.0 mL/kg reflected a likely practical difference (ES = 0.72). The peak VO2 during the TT was significantly higher than VO2max during the RAMP for all participants combined (62.3 ± 6.8 vs 60.5 ± 7.2 mL · kg−1 · min−1, P = .011), and the mean difference ± 90% confidence intervals of 1.8 ± 1.1 mL · kg−1 · min−1 reflected a possible practical difference (ES = 0.25).
These results show that performance and physiological responses to a self-paced TT lasting approximately 3 min differ between sexes. In addition, a TT may provide a valid measure of VO2max.
Almost half of the record 98 events being held at the 2014 Sochi Winter Olympic Games were either not held 20 years ago at Lillehammer or have been substantially modified. The Olympics as a global sports event are not stationary but must adapt and evolve in response to changing demands, just as the remarkable athletes who are competing do. While the Winter Olympics program has steadily grown since Chamonix in 1924, the rate of development has greatly accelerated in the last 20 years. Three factors seem to be instrumental. First, the Winter Olympics program has become more gender balanced. Female hockey teams are battling for gold, and this year women will compete in ski jumping for the first time. Most Winter Olympics sports have equal numbers of events for men and women today, although female participation still lags somewhat behind. Second, many traditional events have been modified by sport-governing bodies toward a more “TV friendly” format. Time-trial starts have been replaced by mass or group starts. “Sprint” and team events have been added to spice up traditional sports like cross-country skiing and speed skating. Finally “extreme” sports like half-pipe and ski-cross have crossed over from the X Games to the Olympics, with some arguing that the Olympics need these popular sports more than the X Games sports need the Olympics. All of these changes create new research questions for sport scientists who are also willing to adapt and evolve.
Øyvind Sandbakk and Hans-Christer Holmberg
Cross-country (XC) skiing is one of the most demanding of endurance sports, involving protracted competitions on varying terrain employing a variety of skiing techniques that require upper- and/or lower-body work to different extents. Through more effective training and extensive improvements in equipment and track preparation, the speed of cross-country ski races has increased more than that of any other winter Olympic sport, and, in addition, new types of racing events have been introduced. To a certain extent this has altered the optimal physiological capacity required to win, and the training routines of successful skiers have evolved accordingly. The long-standing tradition of researchers working closely with XC-ski coaches and athletes to monitor progress, improve training, and refine skiing techniques has provided unique physiological insights revealing how these athletes are approaching the upper limits of human endurance. This review summarizes current scientific knowledge concerning the demands involved in elite XC skiing, as well as the physiological capacity and training routines of the best athletes.
Thomas Losnegard, Håvard Myklebust, Øyvind Skattebo, Hans Kristian Stadheim, Øyvind Sandbakk and Jostein Hallén
In the double-poling (DP) cross-country-skiing technique, propulsive forces are transferred solely through the poles. The aim of the current study was to investigate how pole length influences DP performance, O2 cost, and kinematics during treadmill roller skiing.
Nine male competitive cross-country skiers (24 ± 3 y, 180 ± 5 cm, 72 ± 5 kg, VO2max running 76 ± 6 mL · kg–1 · min–1) completed 2 identical test protocols using self-selected (84% ± 1% of body height) and long poles (self-selected + 7.5 cm; 88% ± 1% of body height) in a counterbalanced fashion. Each test protocol included a 5-min warm-up (2.5 m/s; 2.5°) and three 5-min submaximal sessions (3.0, 3.5, and 4.0 m/s; 2.5°) for assessment of O2 cost, followed by a selfpaced 1000-m time trial (~3 min, >5.0 m/s; 2.5°). Temporal patterns and kinematics were assessed using accelerometers and 2D video.
Long poles reduced 1000-m time (mean ± 90% confidence interval; –1.0% ± 0.7%, P = .054) and submaximal O2 cost (–2.7% ± 1.0%, P = .002) compared with self-selected poles. The center-of-mass (CoM) vertical range of displacement tended to be smaller for long than for self-selected poles (23.3 ± 3.0 vs 24.3 ± 3.0 cm, P = .07). Cycle and reposition time did not differ between pole lengths at any speeds tested, whereas poling time tended to be shorter for self-selected than for long poles at the lower speeds (≤3.5 m/s, P ≤ .10) but not at the higher speeds (≥4.0 m/s, P ≥ .23).
DP 1000-m time, submaximal O2 cost, and CoM vertical range of displacement were reduced in competitive cross-country skiers using poles 7.5 cm longer than self-selected ones.