Electromyography activity of posterior oblique sling muscles during high-speed running in elite soccer players: risk factors for hamstring injury.

OBJECTIVE: This study examined how changing Posterior Oblique Sling muscles (POS) activity during the Prone Hip Extension (PHE) test can influence the activity of POS muscles and the risk of hamstring injury during high-speed running. METHOD: Twenty-four male soccer players were divided into Non-Delayed (NDG, N = 13) and Delayed groups (DG, N = 11) (delay in activation of hamstring and gluteus maximus) based on activity patterns of POS muscles (Gluteus Maximus (GM), Hamstring muscles (H), and contralateral Lumbar Erector Spine (CLES)) during the PHE test. Then, they ran on a treadmill at 20 Km/h, and muscle activity of these muscles was recorded. Before recording muscle activity, we omitted participants with limited range of motion (ROM) to eliminate the effect of ROM on muscle activity patterns. RESULTS: Results showed that GM activities were significantly higher in the NDG at 7–10% of the running cycle, while the DG had greater GM activities at 55–62%. Semitendinosus (ST) activities were significantly higher in the DG at 45–70%, and the NDG exhibited greater ST activities at 95–100%. Biceps Femoris (BF) activities were significantly higher in the DG at 0–15% and 95–100%, while the NDG had higher BF activity at 45–62%. BF -to-GM activity ratio was significantly higher in the DG at 7–11%, and BF -to-Contralateral Lumbar Erector Spine (CLES) activity ratio was higher in the NDG at 52–55%. CONCLUSION: Athletes in DG may have different POS muscle activity patterns compared to NDG, which may increase hamstring injury risk compared to the NDG due to observed activity patterns.