Hamstring Injuries In Football

Injuries to the posterior thigh muscles are the most prevalent muscular injuries in sports. The primary mechanism of injury is sprinting, followed by kicking and rapid stretching of the posterior upper leg. The most common injuries to this area occur when the hamstring muscles are in an eccentric contraction, producing significant forces.

The muscle group located on the posterior upper leg is known as the hamstrings. This group comprises three muscles: on the lateral side, there is the biceps femoris (BF), consisting of long and short heads, whilst on the medial side, there are the semimembranosus (SM) and the semitendinosus (ST).

The hamstring muscles primarily function as hip extensors and knee flexors. Running and walking are fundamental human movement methods. Both involve steps taken using leg muscle force and rebounding off the surface. Walking differs from running due to its double support phase (when both feet contact the ground simultaneously). Running lacks this phase and consists of support, flight (swing), and recovery phases.

In both modes of movement, the hamstrings' eccentric action is crucial. These muscles decelerate lower leg movements, slowing knee joint movements and hip flexion during the swing phase's final part to prepare for heel-ground contact. During the support phase's first half, hamstrings transition from eccentric to concentric work, acting as hip extensors. This requires a rapid change in operation mode due to the large forces involved. The greatest eccentric load on the hamstrings occurs in the swing phase's final part.

Hamstring injuries can occur during rapid running movements or intense ball-kicking in football. In British rugby, 68% of hamstring injuries result from running and sprinting, with only 10% caused by kicking. Studies show that hamstrings are most susceptible to injury during the swing phase's end and the support phase's beginning, particularly after heel-ground contact. Injury risk increases with running speed due to greater hip flexion. About 80% of hamstring injuries involve the biceps femoris long head. The biceps femoris is more prone to injury than the semitendinosus and semimembranosus due to its greater elongation amplitude and smaller knee flexion force moment.

Reducing Hamstring Injury Risk in Sports

Traditional approaches focus on stretching and strengthening the hamstrings. Recent literature emphasises eccentric muscle contractions, as injuries often occur during eccentric hamstring contraction. Some research indicates that eccentric contraction exercises, combined with proper warm-up, stretching, and load control, can reduce injury incidence by 65%. Sprint training within a training microcycle is also crucial, as avoiding it may increase match injury risk due to lack of adaptation.

Guidelines for Reducing Hamstring Injury Risk in Sports

1. Proper warm-up (dynamic stretching)
2. Sprint mechanics training
3. Lumbo-pelvic control exercises
4. Eccentric strength training (hip and knee dominant exercises)
5. Sprint training (300-350 m weekly)
6. Load control (volume and intensity management)
7. Muscular endurance development