INJURY PREVENTION

hamstrings. Similarly if the gluteus maximus is not recruited prior to hamstring activation, the load imposed on the hamstrings will be further increased.

When the piriformis muscle goes into spasm it causes irritation of the sciatic nerve. Anatomically, the piriformis lies deep to the gluteal muscles, its proximal attachment is at the anterior sacral spine and it runs distally to the greater trochanter of the femur. Usually the sciatic nerve passes distally to the piriformis muscle, but in approximately 15% of the population it passes through the muscle (i-3).

The piriformis assists in the abduction and lateral rotation of the hip joint. During the gate cycle the piriformis controls medial rota- tion of the hip during the initial stance phase by contracting eccen- trically on each step. Excessive over pronation will also cause the piriformis to work eccentrically because the tibia rotates medially, causing a strong adduction action in the upper leg. This means the abductors have to work very hard eccentrically in order to keep the leg in line during the gate cycle. Sustained tension in the piriformis muscle can lead to the formation of

massage and exercises to increase suppleness, flexibility stretch- ing, and gentle running at first increasing to sprinting as the limbs become warm.

Evidence-based statistics show that soccer players at the highest level are susceptible to hamstring tears. This fact must question the preparation and training of footballers.

It is important to realise that hamstring muscle injuries, may be quite minor and respond very quickly to treatment, or a major dis- ruption that can take weeks or even months to heal. A quick diag- nosis and identification of which muscle is involved is paramount.

trigger points (figure 1),

usually close to the attachment at the trochanter. This in turn caus- es an apparent limb length discrepancy leading to alteration in the length of the hamstring. Therefore regular assessment of the leg length helps to alleviate the biomechanical dysfunction in the piriformis which can lead to hamstring injuries. If on examination a limb length discrepancy is identified then immediate soft tissue work including muscle energy techniques to the piriformis to reduce its hypertonicity should be undertaken. This type of investigation should be carried out at least two to three times per week with any treatment if required.

A PODIATRIC PERSPECTIVE Injuries to the hamstring muscles are, along with adductor muscle injuries, common in sporting activity where explosive acceleration is necessary. This study will concern itself with the soccer player who falls into this category.

In soccer players hamstring tears are particularly liable to occur in the early stages of the sprint mechanism where the legs tend to be turned outwards. This laterally rotated limb position tends to put the hamstring muscles under greater strain than otherwise would be the case. This situation diminishes however as the individual achieves his/her desired speed and the limb becomes more centrally positioned.

Hamstring portion tears are particularly common in individuals who fail to go through a warming up routine. This should involve

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Playing surfaces – grounds that are either too soft or too hard both play their part in influencing how muscles respond to activity. Too hard a playing surface presents little yield to body weight and activity so requiring adjustments within the musculo- skeletal system. How the body adjusts is dependent on fitness and ability. Too soft a playing surface (often described as a heavy ground) makes the body work harder to complete the task involved. This is because purchase to the ground surface is greater so absorbing the energy of the body as it completes its given task. This energy-sapping situation will seek out muscles that are either weak or suspect due to previous injury or lack of fitness.

The use of video gait analysis (VGA) is essential in determining biomechanical dysfunction of the lower limb. Analysis will help the practitioner decide whether an injury such as a hamstring strain/tear is due to a faulty gait cycle or not particularly if it is recurring or chronic.

BOX 1: MINIMUM REQUIREMENTS FOR A BIOMECHANICAL ASSESSMENT OF THE LOWER LIMB

1. Limb length measurement 2. Recording of lateral and medial rotation of the hip joints

3. Examination of the knee joints – particularly the insertions of the hamstring tendons

4. Examination of the ankle joint(s) and foot with particular reference to sagittal plane movement of the ankle joint(s) and first metatarso-phalangeal joint(s)

5. Recording of heel strike in neutral calcaneal stance position (NCSP), mid-stance relaxed calcaneal stance position position (RCSP), subtalar joint axes and medial longitudinal arches

6. Recording of position of calluses on the feet, which may indicate faulty foot function.

sportEX dynamics 2008;15(Jan):10-14