Effects of team- and individual-based financial incentives on physical activity: a prospective, nonrandomized intervention using the WeChat platform

Physical inactivity remains a global public health challenge, particularly among occupational groups. While mobile technology offers potential for promoting physical activity, evidence on combining team and individual financial incentives via social media platforms in collectivist workplace cultures is limited. This study evaluated the short- and long-term effects of a WeChat-based intervention integrating team and individual financial incentives on physical activity and weight loss in Chinese occupational populations. A quasi-experimental study was conducted across 16 workplaces in Shanghai, involving 680 participants (intervention: n = 387; control: n = 293). The 3-month intervention required daily step goals (10,000 steps) tracked via WeChat, with financial rewards for teams (weekly and final rankings) and individuals (top performers). Outcomes included daily step counts, Body Mass Index (BMI), and waist-to-hip ratio, measured at baseline, 3 months, and 12 months. Analyses used linear mixed-effects models (LMM) and repeated measures ANOVA. During the intervention, the intervention group increased monthly steps by 3003, while the control group decreased by 36 steps (between-group difference: 2967 steps, 95% CI: 2260–3274, P < .001). Subgroups with lower baseline steps (< 6000/day) showed greater increases (5045 vs. 2294 between-group difference: 2751 steps, 95% CI: 2298–3205, P < .001). Participants with normal weight exhibited larger step gains than those with overweight/obesity (3237 vs. 2661, between-group difference: 576 steps, 95% CI: 148–1002, P < .001). BMI and waist-to-hip ratio remained unchanged long-term. Post-intervention, daily steps were significantly reduced during COVID-19 lockdowns compared with the baseline, with no recovery to baseline levels. Combining team and individual financial incentives via WeChat improved short-term physical activity, particularly among individuals with lower baseline activity or normal weight. However, effects diminished post-intervention and did not translate to sustained weight loss. Seasonal factors and pandemic disruptions likely influenced long-term outcomes. The study protocol was approved by the Ethics Review Committee of the Shanghai Municipal Center for Disease Control and Prevention (ChiCTR1900023813,2019/06/13).