ABSTRACT

　This study examined whether home-based, high-speed calf-raise training changes the rate of torque development (RTD) of the plantar flexion, balance performance and the resting muscle hardness of the gastrocnemius medialis (MG) in elderly men. Twentythree healthy elderly men (70-79yr) were randomly assigned to a training (n=13; 73.9±2.9yr) or control group (n=10; 73.2 ±3.3yr). The subjects in the training group performed 8 weeks (3 times per week) of home-based bilateral calf-raise training using body mass. On the other hand, the subjects in the control group were requested to continue their normal daily activities throughout the same period. The RTD of the plantar flexion, the outer circumferential area of center of pressure (COP) displacement during single-leg standing and the resting MG hardness were measured before and after the intervention. The RTD relative to maximal strength of the plantar flexion was calculated as nRTD. In addition, the muscle volume of the plantar flexors was estimated using the muscle thickness of them and the lower leg length. No variables changed in the control group. In contrast, nRTD of the plantar flexion and the resting MG hardness increased and the outer circumferential area of COP displacement during single-leg standing decreased significantly after the intervention in the training group. Our findings indicate that the calf-raise training at home, performed without special equipment or venue, induces improvements of the rapid force generating capability of the plantar flexors and the ability of balance performance. That is, this training program is useful to maintain and/or improve the quality of life for elderly men. Furthermore, from the perspective of muscle mechanical properties, it is suggested that a stiffer muscle can contribute to the higher rapid force generating capability.

DESCENTE SPORTS SCIENCE Vol.38/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE