Lower-limb biomechanics during stair descent: influence of step-height and body mass
Lower-limb biomechanics during stair descent: influence of step-height and body mass
复制标题
下楼梯时下肢生物力学：步高和体重的影响
DOI：
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发表时间：
2008
影响因子：
2.8
通讯作者：
C. Maganaris
中科院分区：
文献类型：
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作者：
M. Spanjaard;Neil D. Reeves;J. Dieen;V. Baltzopoulos;C. Maganaris
总结本研究的目的是检查下楼梯过程中下肢的生物力学，以及通过两种方式增加需求的影响：增加步高和增加体重。10名男性受试者走下一个四阶楼梯，楼梯的高度可以改变。台阶高度为：标准（17 cm），50%下降，50%增加和75%增加。在标准身高下，受试者还穿着一件加重的夹克，携带20%的额外体重。下肢运动学和动力学确定使用运动捕捉和地面反作用力。同时测量腓肠肌内侧（GM）肌肌电图和GM肌束长度使用超声。GM肌束在所有条件下楼梯的触地阶段主动缩短，而根据膝关节和踝关节运动学计算的肌肉-肌腱复合体（MTC）延长。随着步高的增加，GM肌束缩短幅度增大，与踝关节力矩的增加相对应。增加的身体质量并没有改变踝关节或膝关节的时刻在第一个接触阶段的一步下来，由于战略的变化，后腿，而不是领先的腿，支持额外的质量。因此，在触地阶段，GM肌束缩短的量也不随体重增加而改变。我们的研究结果表明，关节力矩的增加与肌束缩短的量有关，肌束缩短发生在MTC延长的同时，从而拉伸了弹性肌腱组织。
SUMMARY The aim of the present study was to examine the biomechanics of the lower limb during stair descent and the effects of increasing demand in two ways: by increasing step-height and by increasing body mass. Ten male subjects walked down a four-step staircase, the height of which could be altered. The step-heights were: standard (17 cm), 50% decreased, 50% increased and 75% increased. At the standard height, subjects also walked down wearing a weighted jacket carrying 20% extra body mass. Lower limb kinematics and kinetics were determined using motion capture and ground reaction forces. Also measured were gastrocnemius medialis (GM) muscle electromyography and GM muscle fascicle length using ultrasonography. GM muscle fascicles actively shortened during the touch-down phase of stair descent in all conditions, while the muscle–tendon complex (MTC), as calculated from the knee and ankle joint kinematics, lengthened. The GM muscle fascicles shortened more when step-height was increased, which corresponded to the increase in ankle joint moment. Increased body mass did not alter the ankle or knee joint moment in the first contact phase of a step down; due to a change in strategy, the trailing leg, instead of the leading leg, supported the extra mass. Hence, the amount of GM muscle fascicle shortening, during the touch-down phase, also did not change with added body mass. Our results suggest that the increase in joint moments is related to the amount of fascicle shortening, which occurs whilst the MTC is lengthening, thereby stretching the elastic tendinous tissues.