Sex differences in quadriceps rate of torque development within 1 year of ACL reconstruction

Abstract Objectives To investigate the effect of sex on measures of quadriceps strength, rate of torque development, and knee function during the first year following ACLR. Design Cross-sectional; Setting University community; Participants Sixty individuals (29 men) with unilateral ACLR in the last 12 months. Main outcome measures Participants completed bilateral knee extension maximal voluntary isometric contraction (MVIC, Nm/kg) strength assessments. Rates of torque development (Nm*kg -1 *s -1 ) were assessed from contraction initiation to 100 ms (RTD 100 ) and from 100 ms to 200 ms after contraction initiation (RTD 200 ). The effects of sex MVIC strength, RTD, and limb symmetry were assessed using separate ANCOVAs. Results Women displayed weaker involved limb (Men = 2.72 ± 0.72 Nm*kg -1 , Women = 2.01 ± 0.50 Nm*kg -1 , p -1 , Women = 2.66 ± 0.58 Nm*kg -1 , p 100 (Men = 8.36 ± 3.16 Nm*kg -1 *s -1 , Women = 6.50 ± 2.41 Nm*kg -1 *s -1 , p  = 0.01) and RTD 200 (Men = 9.49 ± 3.45 Nm*kg -1 *s -1 , Women = 9.49 ± 3.45 Nm*kg -1 *s -1 , p Conclusions Within the first year after ACLR, women displayed bilateral quadriceps weakness and slower involved limb quadriceps RTD when compared to men. Specific focus on facilitating quadriceps hypertrophy and improving neural drive to the quadriceps is indicated when treating female patients attempting to make a return to sport after ACLR.