Leisure time sedentary behavior, physical activity and frequency of protein consumption on lower extremity strength and lean mass

BACKGROUND/OBJECTIVES: The purpose of this study was to evaluate the independent and combined associations of moderate-to-vigorous physical activity (MVPA), leisure time sedentary behavior and daily protein consumption on lower extremity muscular strength and lean mass. SUBJECTS/METHODS: Data from the 1999-2002 NHANES were utilized (N=1080 adults 50-85 y). Leg lean mass was estimated from dual-energy x-ray absorptiometry scans. Knee extensor strength was assessed objectively using the Kin Com MP dynamometer. MVPA and leisure time sedentary behavior were assessed via questionnaire, with the number of meals per day of ⩾30 g of protein per meal assessed via a 'multiple pass' 24-h dietary interview. RESULTS: Meeting MVPA guidelines (β=16.3, P=0.02) and consuming at least two meals per day of ⩾30 g of protein per meal (β=28.8, P=0.02) were independently associated with greater lower extremity strength, whereas sedentary behavior was not (β=11.6, P=0.23). Finally, there was no evidence of a three-way interaction of these behaviors on lower extremity strength (β=-8.7; P=0.70) or lower extremity lean mass (β=144.5; P=0.75). CONCLUSIONS: Although MVPA and frequency of protein consumption of ⩾30 g of protein per meal were independently associated with lower extremity lean mass and strength, the results of the present study do not provide evidence to suggest that there is a three-way interplay between MVPA, sedentary behavior and frequency of protein consumption ⩾30 g of protein per meal on lower extremity lean mass and strength.