Effects of lower leg muscle quality on gait variability in community-dwelling older and healthy young adults.

[Purpose] We aimed to determine whether lower leg muscle echo intensity, an indicator of muscle quality, is a useful predictor of gait variability after examining the relationship between physical activity and gait variability in community-dwelling older and healthy young adults. [Participants and Methods] This study comprised two tasks. In the first task, 18 older and 25 young adults were included as participants. We examined the relationship between the amount of physical activity and gait variability in both groups. In the second task, muscle echo intensity related to gait variability in each group was measured using ultrasound echoes after identifying common factors related to gait variability in 19 older and 19 younger adults, and trends were compared. [Results] In the first task, gait variability was significantly higher in the younger group than in the older group. A significant negative correlation was found between the amount of physical activity and gait variability in both groups. In the second task, multiple regression analysis was performed for gait variability, and lower leg muscle echo intensity was identified as a significant factor. There was no difference in the correlation coefficient between gait variability and lower leg muscle echo intensity between the two groups. [Conclusion] Lower leg muscle quality was one of the causes of gait variability, suggesting that it is a useful predictor of gait sway status.