The Impact of Hamstring Injuries on Season Best Performance at the Return-To-Sport Phase: A Survey of Track Runners in High-Altitude Training Camps in Kenya

Abstract

Background: Hamstring injuries are prevalent among runners, often resulting from sprinting techniques during acceleration. Such injuries frequently force athletes out of competition, impacting their performance and revenue. The rehabilitation period varies depending on the injury's nature; muscle bulk injuries generally heal faster than those involving the tendon. This study aimed to evaluate the impact of hamstring injuries on track runners’ performance during the return-to-sport phase of rehabilitation in high-altitude regions of Western Kenya.Design and Method: The study was conducted in accredited training camps in Western Kenya, with ethical approval from the JKUAT Ethics and Review Committee and NACOSTI. The Functional Assessment Scale for Hamstring Injuries (FASH) was used for injury screening, and an observational checklist recorded conventional rehabilitation strategies. A desk review assessed athletes' performance before injury. Post-rehabilitation performance data was collected and analyzed using SPSS version 25. Moderator effect analysis and multi-linear regression were conducted to determine the impact of injury on performance. Results: Out of 415 athletes screened, 221 (30.3%) had hamstring injuries. Among these, 72 (32.6%) experienced severe pain during static stretching, 71 (32.1%) during 30-meter sprints, and 69 (31.2%) during full weight-bearing lunges. Severe injuries were more common in males (93.8%, n=61) compared to females, although no significant relationship between gender and injury severity was found (p > .05). A dependent t-test revealed significant differences in performance times before and after injury, with average completion times increasing from 0:38:33.18 to 0:40:04.16, indicating a 1:30.97 increase (t (220) = -6.747, p < .001). Pearson correlation analysis showed a significant positive relationship between pain during sprinting, discomfort during partial and full weight-bearing lunges, and the time difference pre- and post-injury (p < .05). Regression analysis indicated that 4.8% of the variation in performance time after injury could be attributed to the injury severity (R² = .048, F (1, 117) = 5.85, p = .017). The severity of the injury significantly predicted performance time on return to sport (β = .048, t = 2.419, p = .017). Deviations in performance times post-rehabilitation included 24 seconds in 800m, 21 seconds in 1500m, 31.7 seconds in 3000m, 45 seconds in 5000m, 4 minutes in 10000m, 5 minutes in half-marathon, and 16 minutes in the 42km marathon. Conclusion: The study highlights the need for a standardized treatment protocol for hamstring injuries in Kenya. Developing such protocols will help sports physiotherapists and support staff provide consistent and effective rehabilitation, improving athletes’ return-to-sport outcomes. Further research is recommended to explore the prevalence of hamstring injuries in Kenya and to refine rehabilitation practices.