Evidence-Based Strength Training: Gluteus Medius, An Update

To build upon my previous post regarding Evidence-based Strength Training of the Gluteus Medius, I wrote the following article for MedBridge Education…

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Pain and Gluteal Strength

The gluteal musculature has been implicated in many different pathologies due to its potential impact on lower extremity biomechanics. During weight bearing, the femur moves about a fixed patella and therefore excessive femoral internal rotation and adduction results in increased contact directed primarily at the lateral facet of the patella¹. Just 10° of IR can lead to a substantial decrease in PFJ contract area and a 50% increase in joint stress. Coinciding with these findings, Souza et al.² found that females with patellofemoral pain syndrome (PFPS) demonstrated greater peak hip internal rotation compared to the control group during running, drop jump, and step down. The PFPS group also demonstrated 14% weaker hip abductor strength and 17% weaker hip extensor strength. Wilson et al³, Noehren et al⁴, and Nakagawa et al⁵ found that individuals presenting with PFPS demonstrated increased hip adduction during running, jumping, and single-leg squats. This excess femoral adduction creates an increased valgus force about the knee joint, which in turn causes increased loading of the lateral patellofemoral joint. In addition to patellofemoral pain, a hip etiology or influence has also been implicated in iliotibial band syndrome⁶, anterior cruciate ligament rupture⁷, and achilles tendinopathy⁸.

Gluteal strengthening and Rehabilitation

In support of a gluteal etiology, several studies have found the effectiveness of gluteal strengthening in the treatment of lower extremity disorders. A recent systematic review conducted by Santos and colleagues⁹ found gluteal strengthening decreased the highest intensity of pain experienced during the previous week, pain when ascending and descending stairs, and pain while squatting or sitting for prolonged periods amongst individuals diagnosed with PFPS. Additionally, with regards to rehabilitation following anterior cruciate ligament reconstruction, the inclusion of hip strengthening appears to improve sagittal plane dynamic balance at three months post-ACLR as compared to traditional rehabilitation¹⁰.

EMG Activity and Exercise Goals

According to Reiman et al.¹¹ and Escamilla et al.¹², moderate electromyographic activity (EMG) activation (21-40% MVIC) is best used to facilitate endurance and neuromuscular re-education; high activation (41-60+% MVIC) in order to promote strength gains.

From Biomechanics to Exercises

Gluteus Medius

Origin: External surface of Ilium between anterior and posterior gluteal lines

Insertion: Lateral surface of the greater trochanter

Primary Function: Abduction of the hip joint; the anterior fibers contribute to hip flexion and hip internal rotation, and the posterior fibers to hip extension and hip external rotation. Additionally, the gluteus medius is responsible for preventing the opposite side of the pelvis from dropping during the stance phase of gait and plays a major role in providing frontal stability for the entire pelvis during walking and other functional activities.

The gluteus medius achieves the highest EMG levels during^13,14:

1. Side-lying plank with hip abduction
2. Reverse clamshell with hip abduction and extension
3. Prone plank with hip extension
4. Reverse clamshell with hip abduction
5. Single-leg Bridge

Additionally, you must consider the interaction of other muscles acting with or against the gluteus medius when determining exercise prescription. It has been proposed that individuals who demonstrate excess femoral internal rotation during functional tasks may be relying too heavily on the tensor fasciae latae to control their pelvis in the presence of weak or inhibited gluteus medius musculature.

Selkowitz and colleagues determined that the following exercises achieved the best Gluteal to Tensor Fasciae Latae Activation Ratio¹⁵:

1. Clamshell
2. Side-step with resistance band
3. Single-leg bridge
4. Quadruped hip extension with knee extended
5. Quadruped hip extension with knee flexed

Finally, when progressing your patient towards more functional closed kinetic chain and sport/activity-specific exercises, the following exercises achieve the highest gluteus medius activation^13,16,17,18:

1. Walking lunge with dumbbell in contralateral hand
2. Unilateral mini-squat
3. Skater squat
4. Unilateral deadlift
5. Unilateral wall squat

Exercise prescription is a multi-faceted decision, which is driven by the individual patient’s goals, functional limitations, and the evidence supporting the treatment of these factors. Using EMG studies to drive the selection of exercise is highly valuable, especially during the early stages of rehabilitation or when attempting to isolate individual muscles and/or groups of muscles. However, there are limitations when comparing different studies due to methodological differences (the type of EMG, patient population, data analysis, etc.). Additionally, due to the cost and time to conduct these studies, there are thousands of exercises that have not been evaluated in the literature. In light of this information, these studies should be used to guide your decision making, it should not override your clinical expertise when accompanied by biological plausibility.

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Continued reading…

      

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