Tracking physical activity in different settings from late childhood to early adulthood in Germany: the MoMo...

Regular physical activity is important for remaining healthy. Most studies on the association between active child- and adulthood were based on small non-representative populations. The purpose of the study was to quantify tracking of leisure-time PA (in and outside sports clubs) for 6 years from adolescence into young adulthood in a representative sample in Germany.

This study was a subsample of the "Motorik-Modul (MoMo) Longitudinal Study" (baseline: 2003-2006, wave 1: 2009-2012). Representative longitudinal physical activity data of N = 947 adolescents were included and collected using the MoMo-physical activity questionnaire (MoMo-PAQ). Stability of different physical activity indices was measured using Spearman's rank-order correlations and ANOVA with repeated measurement with age, sex and socio-economic status (SES) as determinants.

While mean leisure-time physical activity outside sports clubs (LTPA) (F(1,397) = 7.9, df = 1; p < .01), sports club physical activity (SCPA) (F(387) = 4.8, df = 1; p < .05) and overall physical activity (OPA) (F(1,441) = 7.7, df = 1; p < .01) changed significantly over time, no changes in overall sports index (OS index) (F(371) = 3.2, df = 1; p > .05) were observed. Low tracking correlations were found for different physical activity indices (LTPA: r = .094, p < .05; SCPA: r = .248 p = <.05; OPA: r = .211 p < .05; OS index: r = .266 p < .05). Results by sex, age and SES were inconsistent. Analyses of agreement showed different results for determinants and settings.

The results of this representative study were comparable to previous studies and showed significant but low stability. Possible reasons for low stability coefficients are a relatively long timespan between both measurement points and potential effects of the reliability of subjective assessment methods. The results confirm that physical activity is a fluctuating variable. Future studies should examine the determinants of tracking and change in physical activity.