CHANGES IN MUSCLE THICKNESS AND MECHANICAL POWER IN JAPANESE MIDDLE AND OLD AGED WOMEN

为了研究随着年龄的增长，机械功率的下降，力-速度特性和最大功率进行了检查，在上，下肢人体运动。受试者为167名年龄在31岁至82岁之间的健康中老年日本女性，他们没有参加任何日常体育锻炼活动计划。他们充分了解了该项目的内容，并签署了共识。研制了一种专用测力仪，用于测量肘关节屈曲（EF）、膝关节伸直（KE）、髋关节屈曲（HF）和髋关节清洁（HIC）等单关节和多关节运动时的峰值功率（Pp）、力（Fp）和速度（Vp）。在每一个动作中，由电控粉末制动系统提供的测功机的不同的几个负载，得到Pp和Fp-Vp关系。用超声技术测量肌肉厚度。30岁时EE、KE、HF和HIC的Pp平均值分别为108、332、141和486 W，70岁时分别为62、131、55和206 W。随年龄增长，下肢运动功率下降的比率有高于上肢运动的趋势。KE、HF、HIC、EF随增龄下降的比例分别为61%、58%、43%。从随年龄增长的力-速度关系来看，下肢运动如KE、HF和HIC运动，力的下降比速度的下降明显。结果表明，下肢运动功率随年龄增长下降幅度较大的主要原因是肌肉收缩力的下降，而不是收缩速度的下降。这一发现表明，有必要对中老年妇女进行肌肉力量训练，特别是下肢肌肉组织，以防止机械功率随年龄增长而下降。

In order to study the decrease in mechanical power with aging, force-velocity characteristics and maximum power were examined during upper and lower limb human movements. Subjects were 167 healthy middle and old aged Japanese females aged 31 to 82 yrs who did not participate in any daily physical exercise activity programs. They were fully informed the contents and signed to consensus of this project. Special dynamometer was developed for the measurements of peak power (Pp), force (Fp) and velocity (Vp) during mono and multi articular movements such as elbow flexion (EF), knee extension (KE), hip flexion (HF) and gh clean (HIC). In each movements, Pp and Fp-Vp relations were obtained from different several loads of the dynamometer which was provided by the electrically controlled powder brake system. Muscle thickness was measured by ultrasound technique. Mean values of Pp for EE,KE,HF and HIC were 108,332,141 and 486W for thirties and 62,131,55 and 206W for seventies, respectively. Decreased ratio in power with aging had tendency to be higher in lower limb movements compared to that of upper movement. Decreased ratio were 61% for KE and HF,58% for HIC and 43% for EF.Decrease in muscle thickness with aging was more pronounced in lower limb (Quardriceps femoris) than upper one (Biceps brachii). From the force-velocity relations with aging, decrease in force was obvious than velocity for lower limb movements such as KE,HF and HIC movements. It was concluded that the larger decrease in power with aging in lower limb movements was mainly caused from the decrease in force than velocity of muscle contraction. This finding suggests the necessity of muscle strength training for middle and old aged women particularly to the lower limb musculature for preventing the drop-off in mechanical power with aging.