Sharifnezhad Ali, Marzilger Robert, Arampatzis Adamantios
Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
J Exp Biol. 2014 Aug 1;217(Pt 15):2726-33. doi: 10.1242/jeb.100370. Epub 2014 May 6.
The present study investigated the longitudinal growth of the vastus lateralis muscle using four eccentric exercise protocols with different mechanical stimuli by modifying the load magnitude, lengthening velocity and muscle length at which the load was applied. Thirty-one participants voluntarily participated in this study in two experimental and one control group. The first experimental group (N=10) exercised the knee extensors of one leg at 65% (low load magnitude) of the maximum isometric voluntary contraction (MVC) and the second leg at 100% MVC (high load magnitude) with 90 deg s(-1) angular velocity, from 25 to 100 deg knee angle. The second experimental group (N=10) exercised one leg at 100% MVC, 90 deg s(-1), from 25 to 65 deg knee angle (short muscle length). The other leg was exercised at 100% MVC, 240 deg s(-1) angular velocity (high muscle lengthening velocity) from 25 to 100 deg. In the pre- and post-intervention measurements, we examined the fascicle length of the vastus lateralis at rest and the moment-angle relationship of the knee extensors. After 10 weeks of intervention, we found a significant increase (~14%) of vastus lateralis fascicle length compared with the control group, yet only in the leg that was exercised with high lengthening velocity. The findings provide evidence that not every eccentric loading causes an increase in fascicle length and that the lengthening velocity of the fascicles during the eccentric loading, particularly in the phase where the knee joint moment decreases (i.e. deactivation of the muscle), seems to be an important factor for longitudinal muscle growth.
本研究通过改变负荷大小、拉长速度以及施加负荷时的肌肉长度，采用四种具有不同机械刺激的离心运动方案，对股外侧肌的纵向生长进行了研究。31名参与者自愿参加了本研究，分为两个实验组和一个对照组。第一个实验组（N = 10）以最大等长自愿收缩（MVC）的65%（低负荷大小）锻炼一条腿的膝关节伸肌，另一条腿以100%MVC（高负荷大小）、90度·秒⁻¹的角速度，在膝关节角度从25度到100度的范围内进行锻炼。第二个实验组（N = 10）以100%MVC、90度·秒⁻¹的角速度，在膝关节角度从25度到65度（短肌肉长度）的范围内锻炼一条腿。另一条腿以100%MVC、240度·秒⁻¹的角速度（高肌肉拉长速度）在膝关节角度从25度到100度的范围内进行锻炼。在干预前后的测量中，我们检查了静息状态下股外侧肌的肌束长度以及膝关节伸肌的力矩 - 角度关系。经过10周的干预后，我们发现与对照组相比，股外侧肌肌束长度显著增加（约14%），但仅在以高拉长速度锻炼的那条腿上出现了这种情况。这些发现提供了证据，表明并非每种离心负荷都会导致肌束长度增加，并且在离心负荷期间，特别是在膝关节力矩减小的阶段（即肌肉失活阶段），肌束的拉长速度似乎是肌肉纵向生长的一个重要因素。
