Jumat, 13 Agustus 2010

Are Weak Gluteus Minimus Muscles Undermining Your Running Performance – and Exposing You to the Risk of Injury?

So-called weak buttocks have ‘ruined’ more running seasons than perhaps any other single cause of running-related injury.
And it’s for that reason that we devote several sections of Unbeatable Buttocks - for injury-free performance to explaining the role of the gluteus medius in maintaining an athlete’s efficient running technique, discussing how to diagnose whether you (or any of the athletes in your charge) have a weakness in the buttocks area -- and if they do, how best to remediate the situation through appropriate exercise and rehabilitation.
The gluteus medius muscle originates at the top of the ilium (hip bone of the pelvis) below the iliac crest, and runs to the top outside surface of the greater trochanter (outer side of the thigh bone). It is the major abductor of the thigh (lifts it away from the body to the side). The fibres at the front rotate the hip internally and the rear fibres rotate it externally.
During closed kinetic chain actions (foot on the ground), 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 (right leg on the ground), the muscle contracts to slow the downward motion of the left side of the pelvis so that the pelvis doesn’t tilt more then 7 or 8 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, you can see the same weakness in walking (producing a waddling motion or in extremis a limp), and the dysfunction will be more marked when that person runs.
NB: athletes can adopt all sorts of cheating adaptations to their running technique adopt to offload a weak or fatigued gluteus medius muscle, something that sports therapists need to be alert to when making an assessment.
Runners with poor dynamic pelvic stability, (lacking vital gluteus medius strength) 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. For example, from heel strike to mid-stance phase, gluteus medius weakness allows:
• the femur (thigh bone) to shift inwards and internally rotate excessively
• the knee to fall into a knock-kneed position
• the lower leg to rotate internally relative to the foot
• weight to be excessively transferred to inner side of the foot.
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.
So how can such an important muscle become weak? Several factors can contribute:
• Medical – hip rotator tears and congenital dislocation of the hip
• Lifestyle – standing predominantly on one leg with the pelvis swayed sideways and hip joint adducted (the classic hip-hitch slouch, often used by mothers when they stand with a child in their arms)
• Simply sleeping on your side with the top leg flexed and adducted over the other leg: maintaining an elongated position for sustained periods can weaken the glute med.
Fortunately, in Unbeatable Buttocks - for injury-free performance we have the answers for anyone wanting know how to cure their med problems – or to how to avoid them in the first place.
First we tell you how to test for muscle strength in the gluteus medius, using a threefold approach. The discussion includes an actual case study of a runner who was training for his first ever marathon, but who started experiencing pain on the inner side of the knee after just four weeks of training. We take you through both the assessment and the rehabilitation programme he followed to get back on the road to recovery.
NB: our section on testing is valuable for medical professionals, athletes and coaches alike. Several of the exercises are easily performed without requiring the intervention of a sports physiologist or other, similarly qualified individual.
Then we explain how to strengthen the gluteus medius. It is important to note that there is no shortage of source materials to find exercises for retraining glute med function. But not all of them exercise the muscle equally effectively for the different roles required in running-based sports.
By contrast, all of our exercises featured in Unbeatable Buttocks - for injury-free performance meet the following two criteria:
• they are performed in weight-bearing or simulated weight-bearing
• they are performed in neutral hip position or positions of slight hip extension (most glute med exercises are done in positions of hip flexion, which tends to preferentially recruit the TFL in a hip abduction or hip stabilisation role).
Whether you are a sports injury professional, athlete or a coach you'll find something of value in our wide range of strengthening exercises -- they vary from those requiring specialised equipment, to exercises which any athlete or coach can perform at home, outdoors or in the club room.
In addition, we provide full details of an Antipodean programme of the strengthening and maintenance of the gluteus medius, which progresses step-by-step from an initial assessment right the way through to a return to full function. Each exercise described here has a grading to denote its difficulty / complexity, and the progressive programme splits into three main stages plus two additional sub-phases.
The programme even includes a progression chart with milestones, so you can assess and engage your progress (or that of your client) by reference to the relevant milestone. That way you can be certain when you or your client is ready to progress to the next level.
It’s essential information for anyone with a personal and/or professional interest in this area, be they athlete, coach or sports physio.



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