Objectives: To explore relationships between groin pain and adductor squeeze strength in male academy football players over a 14-week period. Design: Longitudinal cohort study. Methods: Weekly monitoring of youth male football players consisted of reporting groin pain and testing long lever adductor squeeze strength. Players who reported groin pain at any time during the study period were stratified into the “groin pain” group while players who did not report pain remained in the “no groin pain” group. Baseline squeeze strength was retrospectively compared between groups. Players that developed groin pain were examined via repeated measures ANOVA at four timepoints: baseline, last squeeze before pain, pain onset, and return to pain-free. Results: 53 players were included (age 14.4 ± 1.6 years). Baseline squeeze strength was not different between players in the “groin pain” (n = 29, 4.35 ± 0.89 N/kg) versus “no groin pain” group (n = 24, 4.33 ± 0.90 N/kg, p = 0.83). At a group level, players with no groin pain maintained similar adductor squeeze strength throughout 14 weeks (p > 0.05). Compared to baseline (4.33 ± 0.90 N/kg), players with groin pain had decreased adductor squeeze strength at the last squeeze before pain (3.91 ± 0.85 N/kg, p = 0.003) and at pain onset (3.58 ± 0.78 N/kg, p < 0.001). Adductor squeeze strength at the point where pain subsided (4.06 ± 0.95 N/kg) was not different from baseline (p = 0.14). Conclusions: Decreases in adductor squeeze strength manifest one-week prior to groin pain onset and further decrease at pain onset. Weekly adductor squeeze strength may be an early detector for groin pain in youth male football players.