Purpose: Determine the impact of preseason and between-seasons changes in individual physical performance on injury risk in elite junior Australian football players and if injuries sustained during a season impact subsequent-season performance improvement.
Methods: This prospective cohort study assessed individual performance measures (sprint speed, jump, agility, and aerobic endurance) during preseason over 4 consecutive seasons. Injury status (injured/not injured) was tracked weekly to determine the relationship between individual performance and in-season injury occurrence. Mixed models were used to determine the relationship between physical performance and injury, and the effect of injury on physical performance improvement.
Results: A total of 206 players played 2 consecutive seasons and were included (17.6 y, 181.9 cm, 75.7 kg). Faster players during preseason experienced higher injury incidence (injuries/season) during that playing season (incidence rate ratio = 0.127; P = .034). Injury incidence was not influenced by between-seasons change in any performance measure. Players injured during their first season maintained their aerobic fitness, which declined in noninjured players (d = 0.39; P = .013). Players who sustained a lower-limb injury during their first season saw smaller improvements in sprint speed than players who did not get injured (d = 0.39; P = .035).
Conclusion: Faster players experience higher injury incidence than slower players and may require specific prevention interventions. Players who experience a lower-limb injury during the playing season do not improve sprint speed between seasons to the same extent as players who do not get injured, highlighting the need for targeted high-speed running ability development as part of rehabilitation.
Keywords: adolescent; athletic training; fitness; injury management; physical performance.