Characteristic analysis of the isokinetic strength in lower limbs of the elderly on training for postural control

The principal objective of this study was to assess the characteristic of muscular strength in the lower limbs of elderly subjects after 8 weeks of postural control training with a postural control training system designed specifically for the elderly. In order to verify the characteristic of muscular strength in the lower limbs, 15 elderly volunteers (training group, TG) took part in a balance training regimen using the postural control training system. An additional 15 elderly volunteers (control group, CG), who were employed as the control group, were also tested for comparison with the training group. To evaluate the effects of the training and the characteristic of the muscular strength, we measured the relevant parameters, such as the sway path and the sway area of center of pressure under different visual conditions and the concentric isokinetic strength of the joints in the lower limbs prior to, during, and after training. In this study, we hypothesized that the participants would evidence better balance control, i.e. smaller postural sway and greater concentric isokinetic strength of the ankle and knee joints, than those who did not participate in the training program. We also assessed the relationship of the COP sway area and the concentric isokinetic strength of the ankle, knee, and hip joints of the elderly subjects. The results demonstrated that the correlation between isokinetic strength of the ankle and knee joints and the postural stability dropped significantly in a negative-linear fashion. However, no significant difference was noted between the concentric isokinetic strength of the hip joint and the postural stability of the subjects. The concentric isokinetic strength of the ankle and knee joints was found to be more relevant to the movement of the lower limbs, which is important in terms of the postural strategy. Via these results, we confirmed the characteristics of muscular strength in the lower limbs of the elderly and the relationship between muscular strength and postural stability. Therefore, the elderly that is reinforced muscular strength of the joints of lower limbs can perform increased postural training capability.