Relationships between intramuscular fat, muscle strength and gait independence in older women: A cross-sectional study

Aim: The objectives of the present study were to examine the relationships between intramuscular fat, muscle strength and gait independence, as well as to clarify the intramuscular fat characteristics of dependent older women. Methods: A total of 25 older women who were unable to walk with or without assistance (dependent group), 22 frail older women (frail group) and 22 healthy older women (healthy group) participated in the present study. The frail participants could walk independently, but showed three or more of the following characteristics: slowness, weakness, weight loss, exhaustion and low physical activity. Outcome measures were quadriceps intramuscular fat determined by ultrasound echo intensity, and quadriceps muscle strength of the dependent, frail and healthy groups. In addition, the degree of gait independence (functional independence measures gait score) was assessed in the dependent and frail groups. Results: Echo intensity in the dependent group was significantly negatively correlated with muscle strength and the functional independence measure gait score (correlation coefficients -0.635 and -0.344, respectively). Furthermore, echo intensity in the dependent group was significantly higher than in the healthy group. There was no significant difference in echo intensity between the dependent and frail groups. Conclusions: The present results suggest negative relationships between intramuscular fat and muscle strength, and intramuscular fat and degree of gait independence in dependent older women. In addition, dependent older women have more intramuscular fat than healthy older women.