The Indirect Role of Gluteus Medius Muscle in Knee Joint Stability during Unilateral Vertical Jump and Landing on Unstable Surface in Young Trained Males

Balázs Sebesi,Petra Mayer,Kitty Vadász,Balázs Meszler,Tamás Atlasz,Márk Váczi,Mátyás Varga,Bence Balázs,Ádám Fésüs,Lívia Vass

doi:10.3390/app11167421

Abstract

(1) In the present investigation, we tested the hypothesis that unilateral countermovement jump performance is associated with knee joint stabilization ability during unilateral landing on unstable surface. (2) Twenty-five male sport students were tested for dynamometric knee extension and flexion, and hip abduction isometric strength. Myolectric activity of vastus lateralis and medialis, gluteus medius, and biceps femoris muscles were measured during unilateral countermovement vertical jump performed on a force plate, and during unilateral landing on unstable surface. (3) Vertical jump impulse negatively correlated with biceps femoris activation at landing. Participants with greater hip abduction force performed greater vertical jump impulse, and activated the biceps femoris less when landing on unstable surface. Furthermore, participants with smaller knee flexion/extension torque ratio increased biceps femoris/vastus medialis activation ratio at landing. (4) We conclude that hip abduction strength is an important contributor to unilateral vertical jump performance. Because biceps femoris is considered the synergist of the anterior cruciate ligament, we also propose that hip abductors are primary frontal plane protectors of the knee joint by reducing knee valgus and stress, allowing for smaller biceps femoris co-activation (secondary protection) at landing on unstable surface.

Highlights

Unilateral lower extremity jumps and landings are very common in ground-contact sports [1,2]
Because biceps femoris is considered the synergist of the anterior cruciate ligament, we propose that hip abductors are primary frontal plane protectors of the knee joint by reducing knee valgus and stress, allowing for smaller biceps femoris co-activation at landing on unstable surface
The post-hoc tests revealed that EMG activity was higher during countermovement jump (CMJ) versus landing (p = 0.0001), and that biceps femoris (BF) activity was lower than the activity of any other muscles (p = 0.001 or less) (Figure 3)

Summary

Introduction

Unilateral lower extremity jumps and landings are very common in ground-contact sports [1,2]. The knee flexor co-activation as well as flexor to extensor strength ratio, known as knee joint stability indicators, have been considered important contributors to knee joint protection during unilateral landings on unstable surface [11]. The gluteus medius muscle interests physiotherapists because it functions as a hip abductor, suggesting a potential role in knee valgus control [13,14,15]. The closest to the focus of the present work is a study by Moisan et al [9], in which individuals with chronic ankle instability demonstrated smaller gluteus medius activation during landing on unstable surface, compared to healthy controls. Despite the fact that the gluteus medius is a pelvic muscle, its strength and/or activation seems to be important in the indirect stabilization of the knee joint during landings as it prevents excessive knee valgus

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Discussion

Conclusion