Comparison of lower leg muscle strength and grip strength for diagnosing slower gait speed in the elderly

OBJECTIVES: Sarcopenia, decreased muscle volume and muscle weakness in the elderly is a serious risk of various adverse outcomes. Current diagnostic procedure for sarcopenia includes gait speed, grip strength, and percentage of skeletal muscle volume. However, lower leg muscle strength decreases much faster than grasp power, and we have evaluated the usefulness of its measurement using a recently developed instrument (Locomoscan). METHODS: Forty-three institutionalized elderly subjects were evaluated for their anthropometrical parameters, body composition, grasp and lower leg muscle strength, and gait speed. They were categorized into 2 groups; gait speed equal to or higher than 0.8 m/s and that below 0.8 m/s. RESULTS: Leg muscle strength per body weight was significantly greater in those with their gait speed equal to or higher than 0.8 m/s, whereas there was no significant difference in other parameters. Receiver operator characteristics analysis has shown that leg muscle alone significantly predicted the greater gait speed. CONCLUSIONS: Lower leg muscle strength can be useful for predicting gait speed.

Associations between serum 25-hydroxyvitamin D3 level and skeletal muscle mass and lower limb muscle strength in Japanese middle-aged subjects

OBJECTIVES: One of the important risk factors of falling is decreased muscle mass and muscle strength. Recently, there has been an increasing concern on the role of vitamin D in muscle strength and physical activity. Aim of our study is to examine the relationships between vitamin D status and muscle mass and muscle strength in middle-aged healthy adults. METHODS: Subjects were 40 healthy volunteers aged 42.0 ± 10.6 years old. Evaluation was made for serum vitamin D₃ metabolites including 25-hydroxyvitamin D₃ [25(OH)D₃] and 24,25-dihydroxyvitamin D₃ [24,25(OH)₂D₃] concentrations, lower limb muscle strength, and dietary intake by food frequency questionnaire. Body composition was measured by dual-energy X-ray absorptiometry (DXA), and appendicular skeletal mass index (ASMI) was calculated as skeletal muscle mass/squared height. RESULTS: 70% of the subjects had vitamin D insufficiency/deficiency (serum total 25(OH)D < 20 ng/mL), and female subjects had significantly lower serum total 25(OH)D level compared with males. Vitamin D insufficiency/deficiency group had significantly higher body fat, lower SMI and muscle strength, probably reflecting higher percentage of female subjects. Serum vitamin D₃ metabolites levels were significantly correlated with whole and site-specific ASMI, and lower limb muscle strength, except for the correlation between serum 24,25(OH)₂D₃ concentration and lower limb muscle strength. In addition, serum 25(OH)D₃ level was a positive significant predictor for both ASMI and lower limb muscle strength, while serum 24,25(OH)₂D₃ level was not their significant predictor. CONCLUSIONS: Serum 25(OH)D₃ level was significantly correlated with both skeletal muscle mass and lower limb muscle strength.