Muscle strains

The muscle's physical characteristics enable it to absorb energy. An injury occurs when the energy generated exceeds this intrinsic capacity. Muscle injuries can be classified into four main groups: 1. Delayed-onset muscle soreness (DOMS) 2. Strains: - First degree: local fibril and filament damage with no solution of continuity - Second degree: interruption of a certain number of muscles fibres without involvement of a grossly recognisable portion of the belly - Third degree: rupture of a large portion of the belly with clinically evident solution of continuity 3. Contusions: - Intermuscular haematoma - Intramuscular haematoma 4. Avulsions: - Osseous - Apophyseal - Muscular In the case of strains, the muscle-tendon junction is particularly at risk due to its lesser extensibility and the sudden reduction of local circulation in the tendon compared with the muscle and the bi-articular muscles, especially the hamstring with their greater number of type 2, fast-contraction fibres [1-3]. The clinical and functional picture of strains is worse the greater the tissue damage (Table 1).