HAMSTRING REHABILITATION PART 1

HAMSTRING REHABILITATION – THE EVIDENCE BASE

By Don Gatherer, MCSP and Kerry Peek, MCSP

Introduction Hamstring injuries are one of the most prevalent to affect sportsmen and women and can represent a significant loss of on-field time. Unfortunately once the hamstrings have been injured, the risk of recurrence is high, particularly if the patient does not receive the correct rehabilitation. It is the aim of this article to address this issue and offer guidance to the practi- tioner through the rehabilitation process of a mid-belly ham- string injury from 72 hours up to return to sport. The principles, protocols and programming have been thoroughly researched and implemented and are intended to be used as an example when formulating a sport and position-specific rehabilitation routine and not a definitive regime.

At the clinic we also integrate throughout the rehabilitation phas- es Cybex dynamometry to phase test and then exercise with con- tinuous passive movements, active assisted, isometric, isokinetic, isokinetic dynamic ramping, concentric and eccentric ramping and isotonic modalities. Dynamometry has not been included in the rehabilitation programme because it may not be readily available.

Overview and evidence-base Anatomy The hamstrings consist of three muscles covering the posterior thigh; biceps femoris is the most lateral with semitendinosus and semi-membranosus making up the medial side. Biceps femoris orig- inates from two heads, the long head shares the common origin of semi-tendinosus and semi-membranosus from the ischial tuberosi- ty, whereas the short head originates from the linea aspera of the posterior femur. The two heads of biceps femoris attach onto the head of the fibula, here the attachment is divided by the fibular col- lateral tendon. Semimembranosus shares its insertion with semi- tendinosus on the medial tibial condyle, although semi-membra- nosus attaches slightly more posteriorly (Fig.1). Semi-membranosus and semi-tendinosus also share their innervation with the long head of biceps femoris, via the tibial division of the sciatic nerve (L5, S1, S2), whereas the short head is supplied by the common peroneal (fibular) division of the sciatic nerve.

The hamstrings produce and control movement at two joints (bi- articular) which no doubt makes them more susceptible to injury. The combined hamstring group is responsible for knee flexion as well as aiding hip extension.

controls lateral rotation of the knee, and the long head has a role in lateral rotation and adduction of the hip.

Semi-membranosus

and semi-tendinosus will produce medial knee rotation as well as assisting in medial rotation and adduction of the hip joint.

Biomechanics Hamstring injuries are particularly prevalent in sports that require

8 SportEX ©1999 Primal Pictures Ltd Figure 1: Posterior view of the femur showing the hamstrings

short bursts of power, acceleration and deceleration, such as soc- cer, rugby, American and Australian rules football. A brief descrip- tion of the biomechanics of the hamstrings during the gait cycle has been given to aid in the understanding of the function of this group in each gait phase (Fig.2).

There are two phases to the gait cycle in walking. These are the stance (weight-bearing portion of the gait cycle) and swing (non- weight bearing portion) phases. Walking dictates that one limb is in contact with the ground at all times. However with increases in speed, the length of the stance phase decreases and periods of time are spent without either leg being in contact with the ground, this is known as the floating phase of running (1). By the time the ath- lete is sprinting the ground contact time is at a minimum with the muscles having to work at a faster rate to produce and control movement.

Hamstring activity is activated in the second half of the swing phase as the hip starts to flex and the knee begins to rapidly extend. During this stage the hamstrings are working eccentrically to control knee extension and hip flexion. As the gait cycle moves into the stance phase, just before heel strike, the hamstrings begin

Gluteus medius Piriformis

Quadratus femoris

Trochanteric bursa of gluteus maximus

Adductor magnus Gracilis

Semitendinosus Semimembranosus Hamstrings

Biceps femoris long head

In addition, biceps femoris also