Feasibility and Preliminary Effects of a Six-Week Equipment-Free High-Intensity Interval Resistance Training Intervention in University Students: A Nonrandomized Pilot Study

Abstract

Abstract Introduction. Physical inactivity is linked to poorer mental health and an increased risk of chronic diseases. High-intensity interval resistance training (HIRT) may be a strategy for improving well-being. The aim of this pilot study was to examine the feasibility and preliminary effects of a six-week equipment-free HIRT program on physical fitness, body composition, and mental health symptoms in university students. Material and Methods. In a longitudinal, non-randomized controlled study, 16 undergraduates (intervention group [IG], n = 7; control group [CG], n = 9; mean age 21.0 ± 2.3 years; 94% male) were assessed before and after the intervention. The IG completed biweekly 31-minute HIRT sessions for six weeks. Outcomes included pushup test, handgrip strength, squat jump, medicine ball throw, Yo-Yo Intermittent Recovery Test Level 1, and mental health measured by the Hospital Anxiety and Depression Scale. Baseline-adjusted ANCOVA tested group differences at post-intervention. Results. Significant group effects favoured the IG for push-up performance (p = .014) and cardiorespiratory fitness (Yo-Yo test; p = .025). No significant between-group differences were found for handgrip strength, squat jump, seated medicine ball throw, body composition, anxiety, or depressive symptoms (all p > .05). Within the IG, total minutes of high-intensity activity were negatively correlated with fat mass (r = -0.856, p = .014) and depressive symptoms (r = -0.943, p = .001). Conclusions. This non-randomized pilot study suggests that a six-week equipment-free HIRT intervention is feasible and may improve upper-body muscular endurance and cardiorespiratory fitness in university students. No significant between-group effects were observed for anxiety, depressive symptoms, or body composition. Associations between time spent at high intensity, fat mass, and depressive symptoms should be interpreted as exploratory and hypothesis-generating, requiring confirmation in adequately powered randomized controlled trials.