BackgroundHealth-enhancing physical activity (HEPA) promotion programs are implemented in sports clubs. The purpose of this study was to examine the characteristics of the insufficiently active participants that benefit from these programs.MethodsData of three sporting programs, developed for insufficiently active adults, were used for this study. These sporting programs were implemented in different sports clubs in the Netherlands. Participants completed an online questionnaire at baseline and after six months (n = 458). Of this sample, 35.1% (n = 161) was insufficiently active (i.e. not meeting HEPA levels) at baseline. Accordingly, two groups were compared: participants who were insufficiently active at baseline, but increased their physical activity to HEPA levels after six months (activated group, n = 86) versus participants who were insufficiently active both at baseline and after six months (non-activated group, n = 75). Potential associated characteristics (demographic, social, sport history, physical activity) were included as independent variables in bivariate and multivariate logistic regression analyses.ResultsThe percentage of active participants increased significantly from baseline to six months (from 64.9 to 76.9%, p < 0.05). The bivariate logistic regression analyses showed that participants in the activated group were more likely to receive support from family members with regard to their sport participation (62.8% vs. 42.7%, p = 0.02) and spent more time in moderate-intensity physical activity (128 ± 191 min/week vs. 70 ± 106 min/week, p = 0.02) at baseline compared with participants in the non-activated group. These results were confirmed in the multivariate logistic regression analyses: when receiving support from most family members, there is a 216% increase in the odds of being in the activated group (OR = 2.155; 95% CI: 1.118–4.154, p = 0.02) and for each additional 1 min/week spent in moderate-intensity physical activity, the odds increases with 0.3% (OR = 1.003; 95% CI: 1.001–1.006, p = 0.02).ConclusionsThe results suggest that HEPA sporting programs can be used to increase HEPA levels of insufficiently active people, but it seems a challenge to reach the least active ones. It is important that promotional strategies and channels are tailored to the target group. Furthermore, strategies that promote family support may enhance the impact of the programs.