Effect of Gluteus Maximus Muscle Strengthening on the Intensity of Quadriceps Muscle Contraction: A Non-Contact ACL Injury Risk Factor

An increased Quadriceps to Hamstrings muscle strength ratio, which leads to development of anterior shear forces on the Tibia, is known as a risk factor for Anterior Cruciate Ligament (ACL) injury. The purpose of the present study was to investigate the effect of Gluteus Maximus Muscle (GM) strengthening exercises on the intensity of Quadriceps Muscle (QFM) contraction at landing.

A total of 25 healthy volunteer females, aged 18-30 years, were assigned into two groups of control (n = 13) and experimental (n = 12) in a randomized control trial. Maximum isometric strength was measured using hand-held dynamometer and the intensity of contraction on the moment of landing to the maximum intensity of voluntary isometric contraction (%MVIC) for GM, QFM, and Hams were measured using surface EMG, respectively. After eight weeks (3 sessions per week) of resistance training on the experimental group, measurements were repeated. Two-factor mixed model ANOVA was used as a significance test and paired samples T-test as the post hoc.

There was a 4.55% non-significant increase in the mean GM strengths in the experimental group. In term of the intensity of contraction, there were a 16.36% increase, a 8.26% decrease, and a 9.21% increase all of which were significant in the experimental group (P≤0.05), and a 2.93% increase, a 4.73% decrease, and a 4.3% increase, all non-significant, in control group, for GM, QFM and HAMS, respectively.

These results suggest that GM strengthening exercises along with HAMS could be effective in decreasing the intensity of QFM contraction, preventing anterior translation of Tibia, and decreasing ACL injury, as a consequence.