Effect of a Structured Active Break Program on Indicators of Muscle Fatigue and Perceived Physical Load in Administrative Staff of the State University of Bolívar
DOI:
https://doi.org/10.70577/asce.v5i1.730Keywords:
Active Breaks, Muscle Fatigue, Occupational Health, Cluster Randomized Trial, Mixed Linear Models, Borg CR-10, NASA-TLX.Abstract
Objective. To evaluate the effect of a structured active break program on muscle fatigue and perceived physical load in university administrative staff compared to a control group maintaining their usual work routine. Design. Cluster randomized controlled trial with parallel groups and pre- and post-intervention measurements over 12 weeks. Randomization was performed at the administrative unit level to minimize contamination bias. Participants. 120 administrative workers from Universidad Estatal de Bolívar (Ecuador); the final analysis included 112 participants (57 intervention, 55 control). Intervention. The intervention group completed three daily active break sessions (10–12 min each) over 12 consecutive weeks, comprising low-intensity joint mobility, stretching, and muscle activation exercises targeting the cervical, lumbar, and upper limb regions. Measurements and analysis. Muscle fatigue was assessed using the Borg CR-10 scale and perceived physical load using the NASA Task Load Index (NASA-TLX). The intervention effect was estimated through linear mixed-effects models with a group × time interaction term, adjusted for sociodemographic covariates. Effect sizes (Cohen's d, partial η²), 95% confidence intervals, and multiple imputation sensitivity analyses were reported. Results. The intervention group showed significant reductions in muscle fatigue (adjusted Δ = −2.21 points; 95% CI: −2.51 to −1.91; p < 0.001; d = 0.91) and perceived physical load (Δ = −12.2 points; 95% CI: −14.0 to −10.4; p < 0.001; d = 0.83). Sensitivity analyses confirmed the robustness of the findings. Conclusions. A structured 12-week active breaks program produces potentially clinically relevant and statistically significant reductions in both indicators, providing rigorous quantitative evidence to support institutional occupational health policies in Latin American contexts.
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