Up to the six week point after injury the remodelling phase can be said to occur and by this stage the physiotherapist will test the patient to see if they can contract the hamstring muscle against maximal resistance without pain or anxiety. The physio will then ask the patient to perform isotonic muscle contractions in the prone position with larger number of repetitions and lower weights initially, progressing to higher weights and fewer repetitions if no pain is experienced. It is advisable not to be too fast in increasing the weight and force applied to prevent a recurrent injury or a chronic strain.

If a muscle shortens while it is contracting and doing work the contraction is said to be concentric and if the athlete can manage this well then they can move on to working the muscle eccentrically. Eccentric muscle activity exists when muscle contraction is proceeding during which time the muscle is extending in length rather that shortening. Since eccentric muscle work is maximally stressful for a muscle this type of rehabilitation should be closely supervised. The starting position is on the front with the lower leg flexed to ninety degrees with an ankle weight and then lowering the leg down to the floor with close control.

This process continues as long as the injured area is not painful until the affected leg can perform as strongly as the unaffected leg (within 10 percent or so) then the programme can be progressed to a more active and vigorous one. During the whole programme the hamstring is regularly stretched to promote healing in a lengthened position and return it to the same length as the unaffected side. The functional stage of hamstring healing is the time from roughly two weeks to six months from the time of the injury, depending on the severity of the initial damage. Patients should have no apparent pain, a normal gait pattern and the ability to walk quickly.

Fast walking can be encouraged as a treatment goal and when the patient can manage half an hour without problems short bursts of jogging can be added. Without pain problems developing once half an hour of jogging is achievable then faster running and short lengths of sprinting can be inserted into the treatment plan. Gradual increase in the force and length of the sprinting is allowed, adding quick halts, twists and sprinting again to reflect more accurately the real world manoeuvres which can gradually become more specific to the sport concerned. The physio may now add plyometric exercises to increase the muscle and tendon stresses and deliver the speed and power which is necessary.

Plyometric exercises are designed to increase the contractile power of a muscle by stretching it in the preparatory phase of the exercise before it contracts, with typical exercises involving bounding or jumping. A more powerful contraction can be developed in this way and the muscle trained to cope with increased forces in activity. A low stress plyometric exercise is jumping rope or skipping and physios will carefully progress this to sideways jumping over obstacles, jumping up and down differing levels and other varied work.

The athlete can return to their particular sport at very variable times from about 3 weeks after the event up to 6 months if the injury is severe. A physio will check out the athlete in detail to make sure that they do not exhibit any loss of power, tissue length, strength, balance and coordination which may not be visible on superficial testing. Prior to competitive play it is recommended that the athlete warms up well and stretches comprehensively although little scientific evidence is available to back up this advice. An injury to a small part of the muscle or a superficial injury to the muscle may allow someone to return to their sport in the shorter time period.

In a study it was found that athletes who required more than one day to be able to walk normally without pain were more likely to need a longer time of rehabilitation over the three week mark. Typical medications recommended are non-steroidal anti-inflammatory drugs to reduce the inflammatory reaction and potentially speed healing.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapist, back pain, orthopaedic conditions, neck pain, injury management and Sheffield Physiotherapist. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.