Effect of Hip Flexion Angle on the Hamstring to Quadriceps Strength Ratio — Hamstrings Perform Better at 90 Degrees

According to the authors, the purpose of this study was to compare the hamstring to quadriceps ratio (H:Q) obtained from three different hip flexion angles …

90°, 60°, and 120°

Seventy-three young athletes performed maximum isokinetic concentric and eccentric knee extension and flexion efforts at 60 °·s-1 and 240 °·s-1 from hip flexion angles of 90°, 60°, and 120°. The conventional (concentric to concentric), functional (eccentric to concentric) and mixed (eccentric at 30 °·s-1 to concentric torque at 240 °·s-1) H: Q torque ratios and the electromyographic activity from the rectus femoris and biceps femoris were analyzed.

The conventional H:Q ratios and the functional H:Q ratios at 60 °·s-1 did not significantly differ between the three testing positions (p > 0.05).

Greater Functional Torque 240 °·s-1 (Hamstrings were stronger) at 90 degrees. Testing from the 90° hip flexion angle showed a greater functional torque ratio at 240 °·s-1 and a mixed H:Q torque ratio compared with the other two positions (p < 0.05). The hip flexion angle did not influence the recorded muscle EMG activation signals (p > 0.05). For the range of hip flexion angles tested, routine isokinetic assessment of conventional H:Q ratio and functional H:Q ratio at slow speed is not angle-dependent. Should assessment of the functional H:Q ratio at fast angular velocity or the mixed ratio is required, then selection of hip flexion angle is important.

ExerciseReports.com Note: The greater strength with hip flexion at 90 degrees might be caused by optimal length-tension relationship of the hamstring muscles at hip flexion at 90 degrees.

Researchers located at the Laboratory of Neuromechanics, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Greece.

Kellis E, Ellinoudis A, Kofotolis AN. Effect of Hip Flexion Angle on the Hamstring to Quadriceps Strength Ratio Sports (Basel). 2019 Feb 15;7(2)