Author(s): IGUCHI, J., YANASE, K., KUZUHARA, K., FUJISAWA, Y., HOJO, T., NAKAMURA, Y., MATSUKURA, K., MOCHIZUKI, C., YAMASHITA, D., Institution: KYOTO UNIVERSITY OF ADVANCED SCIENCE, Country: JAPAN, Abstract-ID: 374

INTRODUCTION:
Groin pain is commonly observed in athletes who participate in multidirectional sports such as soccer. The purpose of this study was to longitudinally examine how training load and recovery status (sleep quality and quantity) during the in-season affect the adductor muscles, which are most frequently associated with groin pain.
METHODS:
Eight collegiate male soccer players who had recently (within the past year) experienced groin pain participated in this study. (age: 20.3 ± 0.7 years). To explore the mechanisms of groin pain, monthly assessments during the in-season (September to November in 2024) included adductor muscle stiffness via ultrasound elastography, sleep quality, training load (session-RPE), the Copenhagen Hip And Groin Outcome Score (HAGOS), handheld dynamometer–measured muscle strength and countermovement jump (CMJ) performance. Repeated measures ANOVA (or Friedman test) and paired t-tests examined temporal and seasonal changes in ΔYoung% ([(late-season value in November − early-season value in September) / early-season value] × 100). Variables identified as showing significant time effects were further examined for associations with ΔYoung% using month-specific simple linear regression models, with Holm-adjusted p-values.
RESULTS:
Adductor muscle stiffness significantly increased from early to late season (ΔYoung%, p < 0.05). Significant time effects were observed for RSI_mod, RFD during the yielding phase (Yielding_RFD), Unload_Time and HAGOS-QOL (p < 0.05), and these variables were entered into month-specific simple linear regression models to examine associations with ΔYoung% (Holm-adjusted p-values). No month-specific associations survived Holm correction; however, several predictors showed trend-level (uncorrected) associations with ΔYoung% (p < .10).
CONCLUSION:
Adductor muscle stiffness increased from early to late in-season in collegiate male soccer players with a recent history of groin pain. Significant time effects were also observed in RSI_mod, Yielding_RFD, Unload_Time, and HAGOS-QOL, indicating concurrent changes in neuromuscular performance and patient-reported outcomes. However, month-specific simple regression models did not show associations with ΔYoung% that remained significant after multiple-comparison adjustment. Overall, seasonal stiffness changes appear multifactorial, supporting the need for larger prospective studies to clarify links with performance, recovery, and groin pain risk.