Examining the effect of team sport and associated training loads on changes in body composition : a systematic review and meta-analysis

Background: The monitoring of body composition together with training load provides an informative, comprehensive assessment of training effectiveness, adaptive responses, and physiological status to strengthen athlete management and development. Currently, this relationship has yet to be fully synthesized in team sport and warrants investigation. Objectives: The aim of this systematic review and meta-analysis was to synthesize the current literature regarding the effects of team sport and associated training loads on body composition changes. Methods: A systematic search was completed according to PRISMA guidelines in MEDLINE, EMBASE, CINAHL, and SPORTDiscus databases to identify articles that examine the relationship between team sport, training load, and changes in body composition. A random-effects meta-analysis was performed to analyze changes in body mass (kg), body fat (%, kg), and lean body mass (kg). Results: The database search yielded 4,594 studies, with six studies meeting all eligibility criteria for inclusion. Meta-analysis demonstrated that playing elite/professional level team sport is associated with small reductions in body fat percentage (SMD: -0.37, 95% CI [-0.74 to -0.01], p = 0.04). These changes appear to be associated with reductions in fat mass (SMD: -0.33, 95% CI [-0.68 to 0.02], p = 0.07), while body mass (SMD: -0.02 [95% CI -0.25 to 0.21], p = 0.87) and lean body mass (SMD: 0.02, 95% CI [-0.26 to 0.29], p = 0.91) tend to be maintained. Inconsistencies and diversity in training load methodologies and reporting resulted in unclear evidence depicting the moderating effect of training load; however, preliminary findings suggest that excessive volumes of high-speed running/sprinting loads may negatively impact body composition, while increasing accelerations/decelerations may provide an effective and efficient means to increase intensity, improve conditioning, and optimize adaptation. Conclusions: Findings from this work suggest that body composition changes as an effect of the cumulative factors and stimuli of elite/professional team sport. Further research is warranted to ascertain the effect of training loads on these changes, with an aim to standardize the quantification and reporting of these loads as well as improved nutritional reporting.Education, Faculty ofKinesiology, School ofGraduat