Split-set resistance training in-season increases maximal vertical power without enhancing athletic performance: a comparison with failure training in youth handball players.

BACKGROUND: We tested the hypothesis that splitting resistance training sets would increase lifting velocity and lead to superior athletic performance adaptations, without compromising strength or muscle hypertrophy, compared to volume-matched sets performed to failure in youth handball players.

METHODS: Thirty resistance-trained youth handball players (8 females, 22 males; 18±2 years) completed a seven-week lower-body program performed either as all sets to failure (FAILURE) or volume-matched with repetitions split into double the number of sets (SPLIT). Pre- and post-intervention testing included one-repetition maximum (1RM) back squat (BS), squat jump (SJ) force-velocity (FV) profiling, one-legged jump and reach (JR), 20 m and change of direction (COD) sprints, and ultrasound assessment of the quadriceps cross-sectional area (CSA).

RESULTS: The mean propulsive training velocity was significantly higher in SPLIT compared to FAILURE (P<0.05). Both groups showed similar improvements in 1RM (15%, both P<0.001) and unloaded SJ height (6%, both P<0.02), with no significant between-group differences in regional or muscle-specific hypertrophy (P>0.05). However, only SPLIT increased maximal vertical power (P<inf>max</inf>, P<0.05) in the FV profile, with a medium effect on theoretical unloaded velocity (V<inf>0</inf>, ES=0.52, P=0.06). No changes were observed in JR, 20 m sprint, or COD performance in either group (all P>0.1).

CONCLUSIONS: These findings indicate that split set resistance training increases training velocity and enhances P<inf>max</inf> but does not translate to superior improvements in strength, hypertrophy, or athletic performance compared to traditional failure training in already trained youth handball players.