Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany.
J Strength Cond Res. 2010 Mar;24(3):668-78. doi: 10.1519/JSC.0b013e3181c088ce.
This study investigated whether different length-restricted strength training regimens affect voluntary explosive concentric power-load curves of the quadriceps femoris (QF) and hamstring (HAM) muscles. Thirty-two athletes were divided into 3 different training groups (G1-G3): G1 performed isometric training at knee joint angles corresponding to long muscle-tendon unit (MTU) length for QF and HAM; G2 conducted concentric-eccentric contraction cycles that were restricted to a knee joint range of motion corresponding to predominantly long MTU length for QF and HAM; and G3 combined the protocols of G1 and G2. Knee joint angle-dependent power-load curves during maximal voluntary explosive concentric knee extensions and flexions were measured for loads corresponding to 40, 60, and 80% of individual 1 repetition maximum at 5 different occasions: 2 times before, after 5 and 8 weeks of training, and 4 weeks post training. Power values of each subject were normalized to the largest value produced at any knee joint position (percent maximum). Obtained by curve fitting, the optimal knee joint angle for power production of QF and HAM remained unaltered throughout the course of the study for all testing loads and training groups. Therefore, different strength training regimens with a common restriction to long MTU lengths failed to induce length-dependent alterations in athlete's voluntary concentric power-load curves of knee extensors and flexors. The approach to develop strength training programs that induce systematic shifts in length-dependent power production of QF and HAM is of direct practical relevance for athletic activities such as cycling, ice skating, and skiing. However, restricting the muscle excursion range during loading seems to be an inappropriate trigger to cause length-dependent alterations in athlete's voluntary concentric power-load curves.
本研究旨在探讨不同长度限制的力量训练方案是否会影响股四头肌（QF）和腘绳肌（HAM）的主动向心爆发力-负荷曲线。32 名运动员被分为 3 个不同的训练组（G1-G3）：G1 在膝关节角度下进行等长训练，该角度对应于 QF 和 HAM 的长肌肌腱单位（MTU）长度；G2 进行向心-离心收缩循环，其限制在膝关节运动范围，主要对应于 QF 和 HAM 的长 MTU 长度；G3 结合了 G1 和 G2 的方案。在 5 个不同的场合测量了最大主动向心膝关节伸展和弯曲时的最大爆发力的膝关节角度依赖的功率-负荷曲线，负荷对应于个体 1 次最大重复次数的 40%、60%和 80%：训练前 2 次、训练后 5 周和 8 周以及训练后 4 周。每个受试者的功率值均归一化为任何膝关节位置（最大百分比）产生的最大功率值。通过曲线拟合，在整个研究过程中，对于所有测试负荷和训练组，QF 和 HAM 的最佳膝关节角度用于产生功率保持不变。因此，对于以长 MTU 长度为共同限制的不同力量训练方案，未能引起运动员主动向心膝关节伸肌和屈肌的负荷曲线的长度依赖性改变。开发力量训练方案以引起 QF 和 HAM 的长度依赖性功率产生的系统变化的方法对于像自行车、滑冰和滑雪等运动活动具有直接的实际意义。然而，在加载过程中限制肌肉行程范围似乎是引起运动员主动向心功率-负荷曲线的长度依赖性改变的不合适触发因素。
