Endurance Outcomes and Between-Group Effect Sizes of a Differentiated Special-Exercise Methodology for University Students with Disabilities during Sitting Volleyball Training

Abstract

This companion study examined endurance outcomes and the between-group statistical robustness of a differentiated special-exercise methodology for sitting-volleyball training in university students with musculoskeletal-system injuries and lower-limb amputation. A three-stage pedagogical experiment (2020–2023) was conducted with 24 students, allocated to a control group (CG, n = 12) and an experimental group (EG, n = 12). The EG followed a purpose-built complex of special, approach, and technical exercises within anaerobic-oriented weekly microcycles differentiated by functional nosology. Six endurance tests were assessed before and after the intervention using paired-samples t-tests; between-group post-intervention differences were additionally evaluated with Welch’s independent-samples t-test, and effect sizes were computed as Cohen’s d with 95% confidence intervals. The EG improved significantly on all six endurance tests (t = 3.51–4.43, p < .01 to p < .001, d = 1.43–1.81, all large), exceeding the CG (d = 0.72–0.86). Between-group comparison favoured the EG on all 16 outcome indicators assessed across the wider research program (d = 0.47–1.08), reaching significance for 3 of 16 despite limited statistical power at n = 12 per group. The differentiated methodology produced large, statistically robust endurance gains, and the effect-size analysis supports its practical value even where between-group significance was not reached.