In a survey of injuries at a professional football club, it was reported that 26.8% of all injuries involved muscles and tendons (Lewin,1989). Muscles and their tendon attachments combine to form what are known as musculo-tendinous units. These musculo-tendinous units provide the force which is necessary for movement. Football is a dynamic sport which requires explosive movements (such as sprinting, jumping, shooting and heading the ball) with large forces generated by muscles and tendons. It is easy to see why over a quarter of all injuries affect these structures.
In order to understand how muscles are injured it is helpful to know how the muscle is made up. The muscle is surrounded by an outer sheath or covering. Inside this outer sheath are bundles of muscle fibres which are known as fasicles and are themselves surrounded by another inner sheath. If you looked at the bundles very closely you would just be able to see the individual muscle fibres. (The muscle fibres are made up of even smaller parts but a microscope is required to see them).
A muscle contracts when two of these microscopic parts link together and slide together (causing the muscle to shorten) or slide apart (causing the muscle to lengthen). If the muscle shortens, the result is movement of a joint in one direction; if it lengthens, it causes movement of a joint in the other direction. The co-ordination of this muscle activity by the brain allows us to perform complex movements such as kicking a football or running.
A muscle strain is damage caused by over-stretching of muscle tissue. In football, this is thought to occur most frequently when movements such as sprinting, stretching for the ball or kicking the ball are carried out in an unco-ordinated manner. The muscle tissue becomes overloaded and reaches a breaking point where a tear or partial tear occurs. The player will experience pain that will persist if he or she attempts to stretch or contract the muscle. Depending on their severity, muscle strains are categorised into Grades 1, 2 or 3:
All muscle strains should be rested and allowed to heal. If the patient continues to play, the condition will worsen. If ignored, a grade one strain has the potential to become a grade two strain or even a complete rupture.
The healing process of a muscle strain begins with an inflammatory response which can last for three to five days. This is a crucial time during which rest and protection of the injured part is vital in order to prevent any further damage. During the inflammatory reaction the body produces chemicals and cells which remove dead muscle fibres and start the repair process. The repair process consists of three stages:
The immediate treatment consists of the 'PRICE' protocol: Protection of the injured part from further damage, Rest, Ice, Compression and Elevation. The aim of this protocol is to reduce bleeding within the muscle tissue. Ice therapy in the form of ice pack applications should be continued for the first three days after the injury (never apply ice directly to the skin). The rehabilitation after this period involves gradually stretching the muscle to elongate the scar tissue and progressively increasing the muscle strength. Once this has been achieved, the player can begin sport-specific exercises, such as running, jumping and kicking. To reduce the risk of re-injury, this should be done under the supervision of a chartered physiotherapist.
The following measures may have the effect of reducing the chances of sustaining a muscle strain:
Adductor muscles - these are commonly injured during football because they are put under a great deal of stress during turning activities. They are also very active during side foot passing.
Hip flexor muscles - these are the kicking muscles at the front of the hip which are very active during shooting and striking a ball.
Quadriceps muscles - these powerful muscles of the thigh are responsible for straightening the knee and are active during running, kicking and jumping.
Hamstring muscles - these muscles are located at the back of the thigh and are most active during running, particularly sprinting, which is when they are most often injured.
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