Fig. 1

Trajectories of daily step count (a) and duration of physical activity > 3 METs (b) of elderly Japanese participants over 5 years of observation. The physical activity was measured objectively by the use of an electronic accelerometer. The markers and solid lines indicate the observed data and predicted trajectories, respectively. HADS-D, depression score of Hospital Anxiety and Depression Scalel; METS, metabolic equivalents