Comparison of Velocity-Based and Traditional Strength Training Methods on Physiological and Motoric Parameters

Traditional resistance training (TRT) often relies on repetitions to failure, which may induce excessive fatigue and impair neuromuscular performance in athletes. Velocity-based training (VBT) offers an alternative by monitoring repetition velocity to prescribe volume. This study compared the effects of VBT with different velocity loss thresholds against TRT on physical performance and muscle adaptations in young soccer players. Twenty-four young male soccer players (age: 16.25 ± 0.53 years) were randomized into three groups: 10% velocity loss (VL10), 20% velocity loss (VL20), and traditional training to failure (TRD). Over a 6-week period, all groups performed squats, hip thrusts, and deadlifts twice weekly at 80% 1RM. Pre- and post-intervention assessments included 5-10-20 m sprints, countermovement jump (CMJ), zigzag change of direction speed, isokinetic muscle strength, and ultrasonographic muscle thickness. Post-intervention analysis revealed significant improvements in 20 m sprint, CMJ, and muscle thickness (rectus femoris and gluteus maximus) across groups (p<0.05). Notably, the VL10 and VL20 groups achieved performance gains similar to or greater than the TRD group but with significantly lower total training volumes. The VL20 group demonstrated the most significant hypertrophic development in the rectus femoris muscle compared to other methods. VBT with low velocity loss thresholds (10-20%) is an effective strategy to enhance explosive strength and hypertrophy while minimizing fatigue accumulation compared to traditional failure training. Specifically, a 20% velocity loss threshold appears optimal for hypertrophy, while 10% is efficient for maintaining power with minimal volume. These methods are recommended for in-season training to manage fatigue while improving athletic performance.