Changes in Velocity Decrement at Different Phases of a 30-Meter Resisted Sprint

Resisted sprint training is one of the most studied methods for developing speed capabilities, especially for elite-level athletes. While traditional sled training relies on a fixed load based on the percentage of body mass, recent research suggests that resistance based on velocity decrement (Vdec) may be a more practical option. This study examines whether Vdec at a given resistance remains consistent or varies across different phases of a 30 m sprint. Twelve male participants with a speed-focused training history were involved in this study. Participants performed 30 m sprint trials, with time splits recorded at 10 m intervals (0–10 m, 10–20 m, 20–30 m) and additional segmental analysis for distances 0–20 m, 10–30 m and the entire 0–30 m sprint. Each participant completed two repetitions at five different resistance levels provided by a cable-driven motorised resistance system (1080 Sprint). The analysis of horizontal force-velocity-power parameters showed moderate variation in force generation of the subjects, with an average theoretical maximal force of 6.33 ± 0.85 N/kg and a relatively consistent maximal velocity of 9.39 ± 0.42 m/s. The study revealed a statistically significant difference in % Vdec (p ≤ 0.05) across different sprint phases, with higher resistance leading to increased differences in the individual phases of the run. Segmental analysis showed a greater % Vdec as sprint distance increased across all resistance levels. These findings highlight the need for a deeper understanding of resisted sprint training for more effective speed development.