The aim of the present study was to design, construct, and scientifically validate a two-dimensional force measurement binding system for cross-country skiing. The system consists of two force measurement bindings. One binding was designed for analysing classic skiing (vertical and anterior-posterior [along the ski] force components) and the other one for skate (freestyle) skiing (vertical and medio-lateral [transverse to the ski] force components). Validation was accomplished by using a three step process 1) accuracy tests for the sensors in two temperatures, 2) sport-specific imitation jump test on standard force plates in a laboratory and 3) comparing the system against force measurement reference systems that are currently used when skiing on snow. During sport-specific imitation jumps, differences in peak forces and impulses between the classic binding and the reference systems ranged from 8.0 % to 19.9 % and were two to three times greater compared to differences between the skate binding and the reference systems (range: -5.9 to 5.5 %).However, high similarity coefficients were observed with both bindings (classic binding: 0.990 to 0.996; skate binding: 0.996 to 0.999) compared to the reference systems. Based on these results, the skate binding was shown to be fully valid for use in field measurements of skate skiing, whereas some improvements have to be performed in the construction and sensor placements for the classic binding (vertical as well as anteriorposterior force component).

IntroductionThis study aimed to 1) determine basic physiological demands during a simulated on-snow cross-country skiing (XCS) race when using grip-waxed skis (all classic XCS techniques [CLASSIC]), versus glide-waxed skis for exclusive double poling (DP) and 2) analyze in which track sections DP is different from CLASSIC under controlled gliding conditions in elite junior and senior skiers.MethodsNineteen male and female elite XC skiers performed 1) two randomized simulated XCS races over 5.3 km using DP or CLASSIC measuring section times, V˙O2, HR, blood lactate, and RPE; and 2) V˙O2peak tests using diagonal stride and DP on treadmill.ResultsThe total group showed no differences in performance or physiological responses between DP and CLASSIC. Elite male skiers achieved improved (~23 s, P < 0.05), male juniors equal (P > 0.05) and females worse (~43 s, P < 0.05) performance with DP versus CLASSIC. Flat and undulating terrain favored DP in men, whereas uphill favored CLASSIC in females (~60 s). Uphill sections showed the greatest group differences. Greater RPE was found in the arms during DP, whereas RPE was greater in the legs using CLASSIC. V˙O2peak in DP was ~95% of V˙O2max.ConclusionsMale skiers demonstrated superior performance with exclusively using DP on a Fédération International de Ski regulation-compliant XCS track, whereas junior males achieved similar, and females’ weaker performance using DP versus CLASSIC. The greatest potential in females is in uphill sections where they distinctly lose time. Exclusive DP might only be beneficial in athletes with high upper-body capacity, and double-pole–specific training and technique. To generalize the findings of the current study, further analysis of snow conditions and course topography is required.

In the sport of cross-country skiing, equipment has a direct influence on results. Ski teams do extensive testing of different ski base grinds and products on a yearly basis. To achieve reliable results, the quality of methods used for testing skis needs to be taken in to account in addition to factors including the physical characteristics of testing personnel and changes in weather conditions. The aim of this study was to introduce a custom-made skitester, that was developed for testing skis on real snow, in laboratory conditions, and to evaluate its precision. The current skitester is capable of glide testing both classic and skate skis as well as kick simulation for the testing of grip waxes. In the present study, glide testing precision was completed in three different conditions. Velocity and pressure of skis were evaluated in three different temperature conditions. During kick simulation, precision was determined in one temperature condition. For glide testing, the precision of the measurement unit was able to distinguish the differences between skis with a relative variation of 0.6–1.1%. However, the track preparation process caused variation. For kick simulation, precision of the measurement unit was slightly higher (2.5%), and track preparation caused less variation. The skitester is capable of distinguishing the differences between both skate and classic cross-country skis with certain limitations.

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