Effects of Ballistic and Traditional Half-Squat Training With Light Loads on Strength, Jump, and Sprint Performance in Young Rugby Players: A Randomized Controlled Trial.

Purpose

This study examined the effects of two 6-week in-season training interventions using light loads (30%-40% 1-repetition maximum) and contrasting strategies: (1) ballistic jump squat (JS) and (2) traditional half squat on strength, jump, and sprint performance in youth rugby players.

Methods

Twenty-five highly trained players completed the randomized controlled trial, training 3 times per week alongside regular rugby practice and competition. Performance assessments included half-squat 1-repetition maximum, mean propulsive velocity, squat jump, countermovement jump, and 30-m sprint speed at 3 time points.

Results

Both groups improved maximal strength and jump performance, with greater gains observed in the JS group (≈7% vs 4% for strength, ≈16% vs 8% for jump performance). The JS group also showed specific improvements in relative strength and heavy-load mean propulsive velocity, whereas the half-squat group improved mean propulsive velocity at lighter loads. A significant group × time interaction was found for countermovement jump, favoring the JS condition. Despite these neuromuscular improvements, sprint performance decreased in both groups, with no between-group differences.

Conclusions

These findings suggest that light-load ballistic training may provide a more effective stimulus for improving strength and power qualities during the in-season period, likely due to its velocity-oriented and fully accelerative nature. However, strength-power gains alone appear insufficient to prevent decreases in sprint performance under congested fixture schedules. From a practical standpoint, incorporating light-load ballistic exercises may enhance neuromuscular performance while minimizing fatigue, but additional sprint-specific training is required to maintain or improve sprint speed in youth rugby players.