Psychosocial Correlates of Sedentary Behavior Reduction Readiness Relevant to Zero-Time Exercise Among Chinese Adults in Sedentary Occupations: Cross-Sectional Study.

backgroundProlonged sitting is an increasingly important public health concern, particularly in occupations that offer few opportunities for conventional exercise. Zero-time exercise (ZTEx) integrates brief muscle-engaging movements into daily routines without requiring dedicated time or equipment and may offer a practical way to interrupt prolonged sitting. However, the motivational, cognitive, and contextual factors associated with intention relevant to ZTEx adoption remain poorly understood.

objectiveThis study examined the association between exercise motivation and general sedentary behavior reduction intention, used as a zero-time exercise-related intention proxy (ZTEx-IP), and assessed model-implied indirect associations involving general self-efficacy and perceived physical activity triggers among Chinese adults in sedentary occupations.

methodsThis cross-sectional survey included 790 adults working full-time in sedentary occupations across 20 provincial-level administrative divisions in China between May and September 2025. Eligible participants reported at least 6 hours of work-related sitting on a typical workday. Standardized questionnaires assessed exercise motivation, general self-efficacy, perceived physical activity triggers, and the ZTEx-IP. Multivariable regression and restricted cubic splines examined graded and nonlinear associations between exercise motivation and the ZTEx-IP. PROCESS Models 4 and 6 estimated covariate-adjusted direct and model-implied indirect associations using 5000 bootstrap resamples.

resultsHigher exercise motivation scores were associated with higher ZTEx-IP scores. Compared with participants in the lowest motivation tertile, those in the highest tertile had an adjusted score difference of 8.49 points (unstandardized regression coefficient, B=8.49, 95% CI 6.43-10.60; P<.001), and the association was nonlinear (P for nonlinearity<.001). In the prespecified ordered model, exercise motivation retained a direct association with the ZTEx-IP (B=0.167, 95% CI 0.088-0.246). Model-implied indirect associations were observed through general self-efficacy (B=0.104, 95% CI 0.057-0.155), perceived physical activity triggers (B=0.157, 95% CI 0.110-0.205), and their prespecified ordering (B=0.025, 95% CI 0.013-0.039). Perceived triggers accounted for a larger increment in explained variance than general self-efficacy (ΔR²=0.054 vs 0.033), and the adjusted outcome model explained 37.6% of the variance in ZTEx-IP scores (R²=0.376).

conclusionsAmong Chinese adults in sedentary occupations, exercise motivation was positively associated with the ZTEx-IP, with model-implied indirect associations involving general self-efficacy and perceived physical activity triggers. The statistical ordering of these associations does not establish that the constructs develop sequentially over time. The comparatively larger trigger-related estimate identifies contextual cue salience as a candidate mechanism for prospective testing but does not demonstrate intervention effectiveness. These hypothesis-generating findings provide a basis for workplace trials of contextually adapted, multicomponent strategies that evaluate actual ZTEx frequency, objectively measured sitting interruptions, adherence over time, and workplace acceptability.