speed in the uphill terrain, and logically follows the pattern found in previous research. 6 , 9 Table 3 Speed and Work Rate (in Absolute Values and Percentage of the Maximal Speed/Work Rate Achieved in the Same Section) for Representative Uphill and Flat Sections During 5-km Cross-Country Skiing With
Pål Haugnes, Jan Kocbach, Harri Luchsinger, Gertjan Ettema and Øyvind Sandbakk
Harri Luchsinger, Jan Kocbach, Gertjan Ettema and Øyvind Sandbakk
Biathlon is an Olympic winter sport, where 3 or 5 (0.8–4 km) laps of cross-country skiing using the skating technique is interspersed with 5-shot series of rifle shooting, alternating between the prone or standing position. One of the traditional racing formats is the individual distance
Glenn M. Street and Robert W. Gregory
While the scientific literature has confirmed the importance of high maximal aerobic power to successful cross-country skiing performance, the same cannot be said of skiing technique or gliding characteristics of skis. The purpose of this study was to determine whether glide speed was related to Olympic race performance. Male competitors in the 50-km freestyle event were videotaped during the 1992 Winter Olympic Games. Glide speeds of the entire field were measured through a 20-m flat section at the bottom of a 150-m, 12° downhill. A significant correlation (r = -.73) was found between finish time and glide speed, showing that the more successful competitors tended to have faster glide speeds through this section of the course. A predictive model of glide speed suggested that the faster glide speeds were due primarily to differences in friction. There was little evidence to suggest that differences in air drag, body mass, or initial speed accounted for the major differences in glide speeds.
Gerald A. Smith, Jill McNitt-Gray and Richard C. Nelson
Cross-country ski technique is undergoing rapid evolution. Alternate stride skating was the dominant technique during the 1985–86 racing season (double poling is synchronized with the “strong” side skate; no poling occurs with the “weak” side skate). High-speed films were made of elite male racers at the Holmenkollen World Cup races, Oslo, Norway (March 1986), skating up a 7° hill. Digitized data were filtered and processed to determine three-dimensional coordinates throughout a complete skating cycle. Ten skiers were analyzed, representing a range of performances. Over the 10-km race length, cycle rates for all skiers were similar; however, cycle lengths were significantly related to cycle velocity. The correlation between cycle velocity and length was r = 0.85. Ski angles were found to be asymmetrical. Weak-side ski angles were negatively related to cycle velocity; strong-side ski angles were similar for all skiers. Center of mass (CM) position throughout the cycle exhibited characteristic differences between faster and slower skiers. CM velocity vector direction was related to cycle velocity. Thus, faster skiers tended to maintain CM motion more nearly aligned with the forward direction.
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.
Thomas Losnegard, Martin Andersen, Matt Spencer and Jostein Hallén
To investigate the effects of an active and a passive recovery protocol on physiological responses and performance between 2 heats in sprint cross-country skiing.
Ten elite male skiers (22 ± 3 y, 184 ± 4 cm, 79 ± 7 kg) undertook 2 experimental test sessions that both consisted of 2 heats with 25 min between start of the first and second heats. The heats were conducted as an 800-m time trial (6°, >3.5 m/s, ~205 s) and included measurements of oxygen uptake (VO2) and accumulated oxygen deficit. The active recovery trial involved 2 min standing/walking, 16 min jogging (58% ± 5% of VO2peak), and 3 min standing/walking. The passive recovery trial involved 15 min sitting, 3 min walk/jog (~ 30% of VO2peak), and 3 min standing/walking. Blood lactate concentration and heart rate were monitored throughout the recovery periods.
The increased 800-m time between heat 1 and heat 2 was trivial after active recovery (effect size [ES] = 0.1, P = .64) and small after passive recovery (ES = 0.4, P = .14). The 1.2% ± 2.1% (mean ± 90% CL) difference between protocols was not significant (ES = 0.3, P = .3). In heat 2, peak and average VO2 was increased after the active recovery protocol.
Neither passive recovery nor running at ~58% of VO2peak between 2 heats changed performance significantly.
Franziska Onasch, Anthony Killick and Walter Herzog
Cross country ski racing is divided into classic and skating races, which both require different skills from athletes. One thing they have in common is the double poling action, occurring in combination with skating push-off or classic striding patterns, or in isolation, as the only propulsive
Pål Haugnes, Per-Øyvind Torvik, Gertjan Ettema, Jan Kocbach and Øyvind Sandbakk
manifestations of localized muscular fatigue in humans . Crit Rev Biomed Eng . 1984 ; 11 ( 4 ): 251 – 279 . PubMed ID: 6391814 14. Zory R , Millet G , Schena F , Bortolan L , Rouard A . Fatigue induced by a cross-country skiing KO sprint . Med Sci Sports Exerc . 2006 ; 38 ( 12 ): 2144 – 2150
Paavo V. Komi
To understand cross-country (X-C) siding it is important to record and identity forces of skis and poles separately and together. They both contribute to the forward progression, but their functional significance may be more complex than that of the ground reaction forces in running and walking. This report presents two methods to record forces on skis and poles during normal X-C skiing. A long force-platform system with four rows of 6-m long plates is placed under the snow track for recording of Fz and Fy forces of each ski and pole separately. This system is suitable especially for the study of diagonal technique under more strict experimental conditions. The second system consists of small lightweight Fz and Fy component force plates which are installed under the boot and binding. These plates can be easily changed from one ski to another, and telemetric recording allows free skiing over long distances and with different skiing techniques, including skating. The presentation emphasizes the integrated use of either system together with simultaneous cinematographic and electromyographic recordings.
Javin C. Pierce, Malcolm H. Pope, Per Renstrom, Robert J. Johnson, Janet Dufek and Charles Dillman
A method for measuring the forces between the shoe and ski and upon the pole has been developed. Instrumented skis and poles are used with a portable data acquisition system that is carried by the skier in the field. Elite, top-level collegiate, and citizen skiers were used as subjects. Skiers performed the diagonal stride, and a marathon skate. Axial force levels at the forefoot were found to reach 164%, and 120% of body weight in the diagonal skate strides, respectively.