Pattern of physical activity can influence its efficacy on muscle and bone health in middle-aged men and women.

Purpose: This study aimed at investigating whether association between physical activity, and bone density and muscle strength depends on daily activity pattern.

Methods: Loading dose of moderate-to-vigorous physical activity (MVPA) was measured using accelerometer on 54 men ( M age  = 54.1 years) and 59 women ( M age  = 52.1 years). Pattern of MVPA was quantified as number and length of MVPA bouts, and the length of break bouts between MVPA bouts. Knee extension torque (KET) and broadband ultrasound attenuation (BUA) of the calcaneus were also measured. Regression analysis was employed to examine the moderation effect of MVPA pattern.

Results: Loading dose had a larger effect on BUA ( b  = .002, p  = .035) and KET ( b  = .004, p  = .01) with the increase of median length of MVPA bout, but had a smaller effect on KET with the increase of maximal length of break bout ( b  = - .015, p  = .024).

Conclusions: This study suggests that pattern of physical activity can influence its efficacy on muscle and bone health.