Hamstring-to-quadriceps ratio across menstrual cycle phases in physically active women: a repeated-measures study

Abstract Objective To evaluate conventional hamstring-to-quadriceps ratio across the menstrual cycle in distinct angular velocities in an eumenorrheic, physically active population. Design Repeated measures within-subjects design. Methods Assessments were conducted in early follicular, ovulatory, and mid-luteal phase in n = 30 eumenorrheic females (age 27.2 yrs ± 4.1; height 168.3 cm ± 5.6; body mass 64.7 kg ± 7.5; body fat 25.9% ± 4.4; fat free mass 47.0 kg ± 4.7, training hours 6.98 ± 3.01, cycle length 28.2 ± 2.9). Isokinetic concentric peak torque values of leg extension and leg flexion at 60°∙s − 1 and 120°∙s − 1 angular velocity were recorded. Participants performed five consecutive maximum repetitions, and the highest values were obtained for further analysis. Subsequently, conventional hamstring-to-quadriceps peak torque ratio (HQ Ratio) was calculated by dividing the highest peak torque value of leg flexion by the highest peak torque value of leg extension. Results HQ Ratio did not differ significantly across menstrual cycle phases at 60°∙s − 1 (F (2,51) = 0.86, p = 0.43), or at 120°∙s − 1 (F (2, 52) = 0.46, p = 0.64). Peak torque values of leg flexion did not differ significantly between menstrual cycle phases at 60°∙s − 1 (F (2,50 = 2.43, p = 0.1) or at 120°∙s − 1 (F (2,52) = 0.48, p = 0.62). Furthermore, peak torque values of leg extension remained unaltered across distinct menstrual cycle phases at 60°∙s − 1 (F (2,50) = 0.5, p = 0.58), and at 120°∙s − 1 (F (2,51) = 0.29, p = 0.75). Conclusion Strength ratios of leg extensors and flexors do not seem to differ between cycle phases. Isokinetic peak torque values of knee extension and flexions seem to remain constant across distinct menstrual cycle phases. Results indicated that conventional isokinetic peak torque testing does not need to be scheduled according to the menstrual cycle.