Training Load Factors and the Prevalence of Overuse Injuries Among Gym Participants: A Cross-Sectional Study

Abstract

Background: Gym-based fitness activities carry a well-documented risk of overuse injury, yet localized data linking specific training load variables to injury burden remain limited, particularly in South Asia.

Objective: To investigate the relationship between training load factors and the prevalence of overuse injuries among gym participants in Karachi, Pakistan, and to identify modifiable risk variables relevant to injury prevention.

Methods: A cross-sectional study was conducted among 279 adult gym-goers (18–40 years) recruited by non-probability convenience sampling from ten fitness centers in Karachi. Overuse injury burden was measured using the validated Oslo Sports Trauma Research Centre (OSTRC) Overuse Injury Questionnaire, alongside a structured form capturing demographic and training load variables (session duration, weekly frequency, exercise modality, structured programming, trainer supervision, and warm-up habits). Data were analyzed in SPSS v29.0 using descriptive statistics, Pearson correlation, and chi-square tests of association; reliability, multicollinearity, normality, and homogeneity assumptions were formally tested.

Results: The sample was predominantly male (64.2%) and aged 21–30 years (62.4%); bodybuilding (39.4%) and weightlifting (24.7%) were the most common activities, with most participants training 5–6 days/week (36.2%) for 1–2 hours per session (47.7%). Overuse injury prevalence was 100%, with mild severity most frequent (58.1%), followed by moderate (28.0%) and severe (14.0%). Muscle strain (51.6%) was the leading injury type, and the shoulder (33.3%) and lower back (29.0%) were the most affected sites; heavy weights (25.4%) and poor technique (22.6%) were the leading reported causes. Only 37.6% of injured participants sought medical care, despite 71.0% reporting disruption to their training routine. The OSTRC scale showed strong internal consistency (Cronbach’s α = 0.89) and strong inter-item correlations (r = 0.54–0.86). Chi-square analysis identified significant associations between overuse injury severity and age (p = 0.01), warm-up habit (p < 0.001), cause of injury (p = 0.03), and medical help-seeking (p < 0.001); BMI, gender, occupation, smoking status, gym experience, training frequency, session duration, activity type, structured programming, and trainer supervision were not significantly associated (all p > 0.05).

Conclusion: Overuse injury is near-universal among gym participants in this population, but its severity is shaped more by age and behavioral factors — particularly warm-up practice and injury causation — than by conventional demographic or training-volume variables. Structured, individualized load management and consistent warm-up promotion, supported by trainer supervision, are warranted injury-prevention targets. Prospective, objectively measured, and multi-site studies are needed to establish causal pathways.