The Acute Effects of Hill Sprinting on Acceleration Kinematics of Subelite GAA Players.

Abstract: Bolger, L, Mooney, R, and Griffin, A. The acute effects of hill sprinting on acceleration kinematics of sub-elite GAA players. J Strength Cond Res XX(X): 000-000, 2025-Resisted sprint training (RST) is an effective method to improve early acceleration (EA) among team sport athletes (TSA). Uphill sprinting (UH), as a mode of RST for improving EA, has not been investigated. The aim of this study was to investigate the acute effects of UH on EA kinematics and compare with EA on a flat surface. Twenty-two subelite Gaelic football and hurling players (age: 20.2 ± 1.16 years; height: 181.1 ± 6.20 cm; body mass: 76.6 ± 8.51 kg) performed 10 m sprints on 3 inclines: 0°, 5°, and 8°. Sprint times were recorded using VALD SmartSpeed timing gates, and kinematics (step length [SL], step frequency [SF], step velocity [SV], ground contact time [GCT], and flight times [FT]) were recorded using the OptoJump Next system. Differences in kinematics across the inclines were investigated using a repeated-measures analysis of variance, with Bonferroni post hoc comparisons used to identify where differences existed. The level of significance was set at p ≤ 0.05. The results indicated significant decreases in SV, SL, SF, and FT, and increases in GCT and sprint times during UH relative to the 0° incline (p < 0.05; large ES for all). The magnitude of change in all kinematics increased with slope, with significant alterations to SL, SV, and sprint times observed (p < 0.05; large ES for all). Kinematics observed during UH seem optimal to facilitate greater force production during ground contacts, consequently increasing SL and improving unresisted EA. The findings suggest that UH has the potential as a form of RST to improve EA among TSA, such as GAA players.