Sex Differences in Maximal and Endurance Adductor Strength: Implications for Athlete Screening and Return to Play

ABSTRACT: Quintana-Cepedal, M, Bailen-Garcia, T, Riestra-Cendan, S, Crespo, I, and Olmedillas, H. Sex differences in maximal and endurance adductor strength: implications for athlete screening and return to play. J Strength Cond Res XX(X): 000-000, 2026-Lower maximal and endurance adductor strength have been identified as modifiable risk factors contributing to groin injury. However, there are currently no data examining the relationship between these 2 variables. This study aimed to determine if maximal hip adduction strength can be predicted by performance on the Brazilian Adductor Performance Test (BAPT) in competitive female and male athletes from different sports. Secondary aims were to compare strength output between female and male athletes in all tests. Baseline demographic characteristics were collected alongside the Hip and Groin Outcome Score and adductor strength. Maximal isometric hip adductor strength was assessed during the 5-second squeeze test, whereas the BAPT evaluated adductor endurance. Linear mixed-effects models were developed with maximal isometric adductor strength as the dependent variable. Strength was quantified as absolute strength (N), normalized strength (N·kg-1), and normalized torque (N·m·kg-1). A total of 131 healthy athletes (n = 253 limbs, 54% female; ≥ Tier 2) were included in the study. This final count excludes 9 limbs that failed to meet the eligibility criteria. The BAPT could not predict maximal strength (R2 = 0.049 to 0.11); however, model fit improved when sex was included as a covariate (R2 = 0.23 to 0.50). Male subjects performed significantly more repetitions in the endurance test (28 vs. 21, d = 0.84) and exhibited higher maximal strength (N·m·kg-1 = 3.08) compared with female subjects (N·m·kg-1 = 2.34; d = 1.23). Because hip adductor maximal and endurance strength correlate poorly, each test evaluates a particular physical capacity and, as such, should not be used interchangeably. Our findings suggest that clinicians should use both tests to screen for potential deficits in either endurance or maximal adduction strength.