Comparisons of hamstrings-to-quadriceps ratio among resistance trained and non-resistance trained males and females

Purpose This study examined hamstrings-to-quadriceps ratio peak torque (HTQ PT ), HTQ cross-sectional area (HTQ CSA ), and HTQ activation (HTQ EMG ) in resistance and non-resistance trained (RT and NRT, respectively) males and females. Methods One hundred-five subjects ( n = 53 females, n = 52 males) participated. PT was taken from maximal voluntary isometric contractions (MVICs) and isokinetic knee extensions and flexions (from 60 to 300°⋅s −1 ) while wearing electromyographic (EMG) sensors on the quadriceps and hamstrings. HTQ PT was PT from leg flexion divided by leg extension. HTQ EMG was EMG amplitude from leg flexion divided by EMG amplitude from leg extension. Ultrasound images quantified quadriceps and hamstrings muscle CSA. HTQ CSA was hamstrings CSA divided by quadriceps CSA. A two-way factorial analysis of variance (ANOVA) and three-way mixed factorial ANOVAs examined differences in HTQ CSA , and HTQ PT and HTQ EMG , respectively. Results For both legs, HTQ CSA was greater for females ( p ≤ 0.011), and HTQ PT at MVIC was less than all other velocities ( p ≤ 0.001), with an increase until 180°⋅s −1 ( p ≤ 0.023), and plateau from 180 to 300°⋅s −1 ( p ≤ 0.070). For HTQ PT on the left leg, RT males had greater HTQ PT than RT females ( p = 0.043) and NRT males ( p = 0.050). HTQ EMG at MVIC was greater than all other velocities ( p ≤ 0.017) on the right leg. For HTQ EMG on the left leg, there were no differences across velocity or among groups ( p ≥ 0.079). Conclusion The present results suggest that some aspects of HTQ may be sex- or training-status dependent. However, the present results generally support the notion that HTQ may be multifactorial in nature and should take into consideration a variety of biomechanical and physiological aspects.