Perrey S, Millet G Y, Candau R, Rouillon J D
Laboratoire des Sciences du Sport UFR STAPS, Besanuon, France.
Int J Sports Med. 1998 Nov;19(8):513-20. doi: 10.1055/s-2007-971953.
The purposes of this study were 1) to examine the occurrence of the stretch-shortening cycle (SSC) in the three principal techniques of ski skating and 2) to test the hypothesis that differences in SSC behaviour may explain the choice of a technique when the grade is altered. Ten highly skilled male cross-country skiers roller skied at 5.3+/-0.1 m x s(-1) using the V1 skate (V1), V2-alternate (V2A), and V2 skate (V2) techniques. Knee and ankle joint kinematics, EMG of the vastus lateralis (VL) and gastrocnemius lateralis (GL) muscles, and roller ski velocity were recorded during the last 40 s of each bout of roller skiing. The existence of an EMG signal during the eccentric phase prior to the thrust, as well as the lack of significant delay between the two phases, showed that SSC occurs in the three techniques of roller ski skating with the exception of 50% of the subjects at the weak side knee with V1. The VL stretching velocity over the eccentric phase was higher (p < 0.005) with V2 and V2A than V1, indicating that less elastic energy was stored in the lower limbs extensor muscles with V1. This could partly explain why this technique is not used on flat terrains during races. However, no differences of average EMG activity or IEMG existed between techniques for either GL or VL during the concentric phase, suggesting that the theoretical advantage due to the SSC behaviour is minor in roller ski skating.
1）研究三种主要的滑雪滑冰技术中拉长-缩短周期（SSC）的发生情况；2）检验以下假设，即当坡度改变时，SSC行为的差异可能解释技术的选择。十名技术高超的男性越野滑雪运动员使用V1滑冰技术（V1）、V2交替技术（V2A）和V2滑冰技术（V2），以5.3±0.1 m·s⁻¹的速度进行轮滑滑雪。在每次轮滑滑雪的最后40秒内，记录膝关节和踝关节的运动学、股外侧肌（VL）和腓外侧肌（GL）的肌电图以及轮滑速度。在蹬地前的离心阶段存在肌电信号，并且两个阶段之间没有明显延迟，这表明除了50%使用V1技术的受试者在弱侧膝关节处外，SSC存在于三种轮滑滑雪技术中。与V1相比，V2和V2A在离心阶段的VL拉伸速度更高（p<0.005），这表明使用V1时下肢伸肌储存的弹性能量更少。这可以部分解释为什么在比赛中该技术不在平坦地形上使用。然而，在向心阶段，GL或VL的技术之间平均肌电活动或积分肌电不存在差异，这表明在轮滑滑雪中，由于SSC行为产生的理论优势较小。
