Relationship between the method of mobility and limb skeletal muscle morphology in institutionalized elderly: An investigation using ultrasound imaging.

This study aimed to provide new insights into the relationship between muscle fiber morphology and means of mobility using ultrasound imaging devices in institutionalized elderly residents, to reduce the progression of sarcopenia.

The participants were 41 elderly people residing in the facility. The participants were divided into “Group 1; walking alone, walking with a cane/Group 2; walking with a wheeled walker/Group 3; wheelchair use/Group 4; transportation by stretcher” according to the means of transportation they used in the facility. The evaluation included the Barthel Index, right and left grip strength, limb circumference, and ultrasound morphometry. Ultrasonographic morphometry was measured by taking pictures of the limbs with an ultrasound imaging device and using image analysis software. A one-way ANOVA was performed on the measured values of each group, and multiple comparisons were performed using the Bonferroni method when significant differences were found. The significance level was set at 5%.

Morphological observations showed that the muscle fibers of the upper arm and thigh were relatively parallel and aligned in Group 1, whereas obscuration of the muscle fiber runners was observed in Group 4. Statistical processing revealed significant differences in “grip strength” and “thigh and lower leg muscle thickness” between the left and right groups (p 0.05). For grip strength, Group 1 was significantly greater than Groups 3 and 4, and Group 2 was also significantly greater than Group 4 (p 0.05). Leg muscle thickness was significantly greater in Group 1 than in Group 4 (p 0.05). Leg muscle thickness was significantly greater in Group 1 than in Group 3 and Group 4, Group 2 than Group 4, and Group 3 than Group 4 (p 0.05).

The group walking alone with a cane or with a wheeled walker showed greater grip strength and lower leg muscle thickness than the group transferred by stretcher, suggesting that walking is an important factor in maintaining muscle strength. In addition, the present study suggests that muscle fiber runs of the upper arm and thigh become misaligned when mobility is difficult.

The clinical significance of this study is that it reveals changes in mobility ability and muscle fiber morphology. In the future, evaluation of how these changes are improved by rehabilitation and exercise interventions will contribute to the development of effective intervention methods to improve mobility and maintain muscle function.