Bobbert M F, Mackay M, Schinkelshoek D, Huijing P A, van Ingen Schenau G J
Eur J Appl Physiol Occup Physiol. 1986;54(6):566-73. doi: 10.1007/BF00943342.
For 13 subjects the performance of drop jumps from a height of 40 cm (DJ) and of countermovement jumps (CMJ) was analysed and compared. From force plate and cine data biomechanical variables including forces, moments, power output and amount of work done were calculated for hip, knee and ankle joints. In addition, electromyograms were recorded from five muscles in the lower extremity. The results obtained for DJ appeared to depend on jumping style. In a subgroup of subjects making a movement of large amplitude (i.e. bending their hips and knees considerably before pushing off) the push-off phase of DJ closely resembled that of CMJ. In a subgroup of subjects making a movement of small amplitude, however, the duration of the push-off phase was shorter, values for moments and mean power output at the knees and ankles were larger, and the mean EMG activity of m. gastrocnemius was higher in DJ than in CMJ. The findings are attributed to the influences of the rapid pre-stretch of knee extensors and plantar flexors after touch-down in DJ. In both subgroups, larger peak resultant reaction forces were found at the knee and ankle joints, and larger peak forces were calculated for the Achilles tendon in DJ than in CMJ.
对13名受试者进行了分析和比较，他们分别进行了从40厘米高度的下落跳（DJ）和反向运动跳（CMJ）。根据测力板和影像数据，计算了髋、膝和踝关节的生物力学变量，包括力、力矩、功率输出和做功量。此外，还记录了下肢五块肌肉的肌电图。DJ的结果似乎取决于跳跃方式。在一组进行大幅度动作（即起跳前大幅度弯曲髋部和膝盖）的受试者中，DJ的蹬地阶段与CMJ非常相似。然而，在一组进行小幅度动作的受试者中，蹬地阶段的持续时间较短，膝盖和踝关节处的力矩值和平均功率输出较大，DJ中腓肠肌的平均肌电活动高于CMJ。这些发现归因于DJ着地后膝伸肌和跖屈肌快速预拉伸的影响。在两个亚组中，DJ的膝关节和踝关节处的峰值合成反作用力都更大，跟腱的峰值力也比CMJ更大。
