Force-velocity profile changes with forearm wearable resistance during standing start sprinting

Horizontal force-velocity (F-V) profiling is a strategy to assess athletes' individual performance capabilities during sprinting. This study investigated the acute changes in F-V profiles during sprinting of fourteen collegiate male sprinters with a mean 100-m sprint time of 11.40 +/- 0.39 s, from a split-stance starting position. The subjects sprinted 30-m with, and without, wearable resistance (WR) equivalent to 2% body mass, attached to their forearms. Sprinting time at 5, 10, 20, and 30-m was assessed using laser technology. External horizontal F-V relationships were calculated via velocity-time signals. Maximal theoretical velocity (V-0), theoretical relative and absolute horizontal force (F-0), and horizontal power (P-max) were determined from the F-V relationship. Paired t-tests were used to determine statistical differences (p <= 0.05) in variables across conditions with Cohen's d as effect sizes (ES) calculated to assess practical changes. Sprint times at 10-m and beyond were significantly increased (1.9-3.3%, p 0.01-0.03, ES 0.46-0.60) with WR compared to unloaded sprinting. The only significant change in F-V with the WR condition was found in relative P-max (system) (-6.1%, p 0.01, ES 0.66). A small decrease was reported in V-0 (-1.0%, p 0.11, ES 0.27), with small to medium ES decreases reported in F-0 (-4.8% to -6.1%, p 0.07-0.21, ES 0.25-0.51) and P-max (-4.3% to -4.6%, p 0.06-0.08, ES 0.32-0.45). The greater changes to F-0 and P-max suggest that forearm WR may be a possible training tool for athletes who wish to focus on force and power adaptation during sprint acceleration from a standing start.