Andersson Erik, Pellegrini Barbara, Sandbakk Oyvind, Stüggl Thomas, Holmberg Hans-Christer
a Swedish Winter Sports Research Centre , Mid Sweden University , Östersund , Sweden.
Sports Biomech. 2014 Sep;13(3):267-84. doi: 10.1080/14763141.2014.921236. Epub 2014 Jun 23.
Cycle and force characteristics were examined in 11 elite male cross-country skiers using the diagonal stride technique while skiing uphill (7.5°) on snow at moderate (3.5 ± 0.3 m/s), high (4.5 ± 0.4 m/s), and maximal (5.6 ± 0.6 m/s) velocities. Video analysis (50 Hz) was combined with plantar (leg) force (100 Hz), pole force (1,500 Hz), and photocell measurements. Both cycle rate and cycle length increased from moderate to high velocity, while cycle rate increased and cycle length decreased at maximal compared to high velocity. The kick time decreased 26% from moderate to maximal velocity, reaching 0.14 s at maximal. The relative kick and gliding times were only altered at maximal velocity, where these were longer and shorter, respectively. The rate of force development increased with higher velocity. At maximal velocity, sprint-specialists were 14% faster than distance-specialists due to greater cycle rate, peak leg force, and rate of leg force development. In conclusion, large peak leg forces were applied rapidly across all velocities and the shorter relative gliding and longer relative kick phases at maximal velocity allow maintenance of kick duration for force generation. These results emphasise the importance of rapid leg force generation in diagonal skiing.
对11名精英男子越野滑雪运动员进行了周期和力量特征测试，他们采用对角步技术，在雪地上以中等速度（3.5±0.3米/秒）、高速（4.5±0.4米/秒）和最大速度（5.6±0.6米/秒）上坡（7.5°）滑行。视频分析（50赫兹）与足底（腿部）力量（100赫兹）、撑杆力量（1500赫兹）和光电管测量相结合。从中等速度到高速，周期频率和周期长度均增加，而与高速相比，在最大速度时周期频率增加而周期长度减小。蹬地时间从中等速度到最大速度减少了26%，在最大速度时达到0.14秒。相对蹬地时间和滑行时间仅在最大速度时发生改变，此时相对蹬地时间更长，相对滑行时间更短。力量发展速率随速度增加而提高。在最大速度时，短跑专项运动员比耐力专项运动员快14%，这是由于更大的周期频率、腿部峰值力量和腿部力量发展速率。总之，在所有速度下都能迅速施加较大的腿部峰值力量，且在最大速度时相对滑行阶段较短、相对蹬地阶段较长，这有助于维持产生力量所需的蹬地持续时间。这些结果强调了在对角滑行中快速产生腿部力量的重要性。
