Fragmented versus traditional resistance training: a randomized controlled trial on muscular strength, endurance, and enjoyment in recreationally trained young adults

Traditional resistance training requires prolonged continuous sessions, which may limit participation among time-constrained individuals. Fragmented resistance training (FRT), derived from ‘exercise snacking,’ may offer a more flexible alternative, but comparative evidence with traditional resistance training (TRT) remains limited. This study examined the effects of 8 weeks of FRT and TRT on muscular fitness and exercise enjoyment in 45 recreationally trained male students (18–25 years, ≥6 months training). Participants were randomised to FRT (three daily short bouts, 1×20 squats each), TRT (one continuous session, 3×20 squats), or a time-matched control group. Training was performed three times/week for 8 weeks using Smith-machine squats, with volume matched and intensity progressing from 40% to 55% of 1RM. Outcomes included 1RM strength, isometric squat force, relative muscular endurance (repetitions at 40% of current 1RM), and PACES enjoyment. Both FRT and TRT significantly outperformed the control in 1RM strength (FRT: +20.59 kg [8.69–32.49], p < 0.001; TRT: +28.93 kg [17.05–40.82], p < 0.001), isometric squat force (FRT: +27.89 kgf [12.15–43.64], p < 0.001; TRT: +35.24 kgf [19.48–51.00], p < 0.001) and relative muscular endurance (FRT: +9.97 repetitions [1.68–18.27], p = 0.020; TRT: +14.11 repetitions [5.84–22.38], p < 0.001), with no significant differences between FRT and TRT group (p = 0.164, 0.353 and 0.320). FRT reported significantly higher enjoyment than TRT (p = 0.034). These findings suggest FRT and TRT produce comparable improvements in strength and endurance under volume-matched conditions, both superior to control. FRT was more enjoyable, indicating it may serve as a practical alternative for time-constrained young adults, though further research on long-term adherence is warranted. Clinical Trial Registration : Chinese Clinical Trial Registry, ChiCTR2500115052.