January 2012; Vol. 1, No. 1: Pages 6-9
Association of vigorous physical activity with age-related, site-specific loss of thigh muscle in women: the HIREGASAKI study
Madoka Ogawa, Naotoshi Mitsukawa, Mark Loftin, Takashi Abe
Abstract
Objectives: To investigate the relationship between age-related, site-specific loss of thigh muscle and accelerometer-determined daily physical activity. Design: Cross-sectional study. Methods: Fifty-one middle-aged and old women aged 52 to 83 years (mean age, 66.0 [SD 7.1] years) volunteered. Muscle thickness (MTH) was measured by B-mode ultrasound at 2 sites on the anterior (quadriceps [QF] 50% of thigh length) and posterior (hamstring [HM] 50% of thigh length) aspects of the thigh. MTH was expressed in terms relative to thigh length (MTH/L). Habitual daily activities on 30 consecutive days were recorded using an accelerometer. Exercise intensity was classified as sedentary to light, moderate, or vigorous. The total duration of each level of exercise intensity was calculated. Physical activity–related energy expenditure was estimated. Results: Age was inversely correlated with the QF-50% MTH/L (r=-0.286, P=.04), but not with the HM-50% MTH/L (r=0.102, P=.47). Age was also inversely correlated with the ratio of QF:HM 50% MTH (r=-0.330, P=.018). Site-specific muscle loss of the thigh was observed in the present sample. There were no significant (P>.05) correlations between the QF:HM 50% MTH ratio and daily step counts (r=0.205), duration of light (r=0.204), moderate-intensity (r=0.145) physical activity, and physical activity–related energy expenditure (r=0.223). However, the QF:HM 50% MTH ratio was significantly correlated with the duration of vigorous physical activity (r=0.287, P=.04). Conclusion: Age-related, site-specific loss of thigh muscle is associated with the amount of vigorous physical activity in middle-aged and old women.
Received November 7, 2011; accepted December 7, 2011