It would be valuable if at risk groups with low physical activity could be identified early and offered targeted intervention. Unfortunately, little is known about the tracking either of total physical activity, moderate to vigorous activity (MVPA) or sedentary behavior in young children.
The aim of the present study was to examine the tracking characteristics of total physical activity (PA), moderate to vigorous activity (MVPA) and sedentary behavior in a relatively large and homogeneous sample of young Scottish children over a two-year period.
The tracking of total physical activity, MVPA and sedentary behavior was examined in Glasgow, Scotland, UK at baseline and 24 months later. Subjects were 21 boys and 21 girls (mean age boys 3.8 SD 0.4 and girls 3.7 SD 0.5 at baseline). Total physical activity, MVPA and sedentary behavior were measured objectively for 7 consecutive days at baseline and 24 months later using the MTI/CSA accelerometer. Time spent in MVPA and sedentary behavior was established using published pediatric cut-offs for accelerometry output. In keeping with recent research in this area, tracking of physical activity, MVPA and sedentary behavior were analyzed in three ways: Spearman Rank correlations, percentage agreements, KAPPA statistics.
For total physical activity Spearman rank correlations ranged from 0.09–0.52; for MVPA Spearman and rank correlations ranged from 0.24–0.44; and for sedentary behavior Spearman rank correlations ranged from −0.09–0.61. Percentage agreement for total physical activity, MVPA and sedentary behavior ranged was 24–38%, 26%–33% and 20%–41% respectively. KAPPA statistics ranged from poor to fair for total physical activity (−0.013–0.005), MVPA (−0.16–0.17) and sedentary behavior (−0.013–0.39).
These results appear to indicate a relatively low to moderate level of tracking of total physical activity, MVPA and sedentary behavior in young Scottish children over a two-year period.