Gluteus medius weakness, Sean Fyfe says, is a likely culprit in many overuse injuries
The gluteus medius should be considered in every running injury. So many athletes with running overuse injuries of the lower limb present with poor gluteus medius function that I have come to the view that the strength and function of this muscle is probably the most important active component in the achievement of a biomechanically efficient running technique. This is not so surprising when you consider that during running you are always either completely in the air or dynamically balanced on one leg. All sports injury practitioners should, I believe, be able to assess and retrain gluteus medius function.
The gluteus medius muscle originates at the dorsal ilium below the iliac crest and inserts at the top outside surfaces of the greater trochanter. It is the major abductor of the thigh. The anterior fibres rotate the hip internally and the posterior fibres rotate externally. The muscle is innervated by the superior gluteal nerve (L4, L5, S1) and gains its blood supply via the superior gluteal artery.
During closed kinetic chain actions, such as the stance phase of running, the normal role of gluteus medius as a mover muscle is reversed, causing it to act as a pelvic stabiliser. So, for instance, during right stance phase, the muscle contracts to slow the downward motion of the left side of the pelvis so that the pelvis doesn’t tilt more than seven to eight degrees from parallel to the ground. If the gluteus medius is not functioning well enough to achieve this control, the athlete is said to have a ‘Trendelenburg gait’. Often, but not always, you may see the same weakness in walking (producing a waddling motion or, in extremis, a limp), and the dysfunction will then be more marked when they run.
The therapist should analyse the function of gluteus medius dynamically and manually. This is not easy. The assessor must be properly alert to the adaptations to running technique that an athlete can adopt to offload a weak or fatigued gluteus medius muscle. To scrutinise the dynamic function accurately, you will need to use video analysis.
Table 1 lists the adaptations or ‘cheating’ movements that occur through the stance phase of running.
|Adaptations||Areas at risk of structural overload|
|1. Trendelenburg||Lumbar spine, sacroiliac joint (SIJ), greater trochanter bursa, insertion of muscle on greater trochanter, overactivity of piriformis and tensor fascia lata (TFL)|
|2. Medial knee drift (valgus position of tibiofemoral joint)||Lateral tibiofemoral compartment (via compression), patellofemoral joint, patella tendon and fat pad, pes anserinus, iliotibial band (ITB)|
|3. Lateral knee drift (varus position of tibiofemoral joint)||Medial tibiofemoral compartment (via compression), ITB, posterolateral compartment, popliteus|
|4. Same-sided shift of trunk (lateral flexion of trunk)||Lumbar spine (increased disc and facet joint compression), SIJ (increased shear)|
Adaptations 2 and 3 clearly cannot occur simultaneously, but a runner’s technique may demonstrate a combination of adaptations, such as a mild Trendelenburg, medial knee drift and an ipsilateral (same-sided) trunk shift.
In my experience, runners with poor dynamic pelvis stability, for which gluteus medius is vital, will decrease their stride length and adopt a more shuffling pattern to reduce the ground reaction force at contact and thereby the muscle control required to maintain pelvic posture.
Weakness in gluteus medius will have implications all the way down the kinetic chain. Take adaptation 2. From heel contact to mid stance phase, gluteus medius weakness allows:
As a result the athlete is at increased risk of any condition relating to excessive and/or prolonged pronation of the foot, such as medial tibial stress syndrome or Achilles tendinitis.
Adaptation 3 is particularly interesting. As it is not often seen in the clinic or documented in the literature, many sports injury practitioners may not be aware of it. It occurs when the athlete is running in excessive anterior tilt and forward trunk position. At ground contact the knee is thrown laterally so that the gluteus medius is offloaded and the foot is forced into a more supinated position. Shock absorption through the lower limb is affected.
As always with muscle testing, it can be difficult to be completely objective in the clinic without lab equipment. But it is quite easy to gain valuable information to complement your dynamic assessment.My approach is threefold. Let’s imagine we are testing the right gluteus medius. First, I ask the athlete to perform the ‘clam’ exercise. In left side-lying, both hips are flexed to 30 degrees with knees bent and hips and feet stacked in line. The athlete has to open their knees while keeping heels together, and most importantly, holding the pelvis completely still. I palpate the gluteus medius for activation. If the pelvis moves despite education on positioning, it means the athlete is unable to isolate the muscle and is trying to recruit ‘cheating’ muscles such as TFL.
The second test is side-lying hip abduction, performed in the same position, but with the right leg straight and in slight hip extension (ie just behind the line of the trunk). The athlete must abduct the leg without hitching the right side of the pelvis (hip hitching would mean they were concentrically recruiting quadratus lumborum and obliques), without falling into anterior pelvic tilt and without letting the pelvis tip back. You can further test the strength of the muscle by getting the athlete to resist your attempts to push the abducted leg downwards. Check for any compensatory or cheating recruitment. To assess muscular endurance, ask the athlete to hold the abducted leg steady for 30 secs.
Lastly I ask the athlete to perform a single- leg squat while I observe control at the foot, knee and pelvis. This also gives me an idea of the stability of the whole lower- limb-to-pelvis chain. All this should be compared to the uninjured side.
A highly informative study by Fredericson et al (2000) upholds the idea that gluteus medius weakness is a contributing factor in ITB friction syndrome; confirms that injured and uninjured sides can be compared to determine weakness; and endorses retraining for strength gains as an effective treatment.
Fredericson measured hip abductor strength in a group of injured male and female subjects, and found an average deficit of 2% in gluteus medius strength on the injured side compared to the uninjured. After a six-week retraining programme, average hip abductor torque improved by 34.9% for females and 51.4% for males; 22 of the 24 injured athletes were able to return to running pain free. Most importantly, at a six-month follow-up, no injury recurrences were reported.
Sean Fyfe is a physiotherapist, tennis coach and director of TFP (Tennis Fitness Physio), a Queensland based company specialising in sports medicine, elite tennis player development, strength and conditioning and childhood motor learning programmes
Illustrations by Viv Mullett
Fredericson M, Cookingham CL, Chaudhari AM, Dowdell BC, Oestreicher N, Sahrmann SA (2000) ’Hip abductor weakness in distance runners with iliotibial band syndrome’ Clin J Sport Med Jul;10(3):169-75 Department of Functional Restoration, Stanford University, California 943055105, USA