Task 1: Introduction

What is the hamstring?

The hamstring refers to the three posterior thigh muscles, the Semitendinosis, Semimembrinosis and Biceps femoris (see fig 1).

Fig 1
Fig 1

The hamstring muscles are primarily used to extend the hip and flex the knee (Abraham.D, 2003). They are also used in walking or running to decelerate the lower leg in the saggital plane (BetterU Inc, 2010).

The hamstring muscles constantly perform eccentric (lengthening) & concentric (shortening) muscle contraction.

Hamstring injuries are extremely common in athletes, especially to ones that participate in sports that require sprinting or high intensity efforts such as AFL, rugby and track & field (AmericanAcademyOrthopaedicSurgeons, 2009). The most common hamstring injury is a strain or tear of one of the three muscles in the hamstring group.

In current times, hamstring injuries have become a major cause of concern for the sport of AFL, with notable severe hamstring injuries occurring to St.Kilda captain Nick Riewoldt, and statistics indicating a rise in the average hamstring injuries per year. (See Q2)

Here are some examples of hamstring injuries:
Fig 2.2

Fig 2.1

Fig 2.3

Fig 2.1 shows a slight pull of the hamstring muscle fibers. This is less severe and would be categorised as a Grade 1.

Fig 2.2 shows an Magnetic Resonance Image (MRI) of a mild strain. It displays a tear of the Biceps femoris (white arrow). This would likely categorised as a Grade 2.

Fig 2.3 displays a severe tear to the hamstring where the tendon has been ripped off the bone. This would be categorised as a Grade 3.