Occurrence Hamstring strain is the most common single injury in elite soccer. To prevent these injuries and to optimise the rehabilitation it is important to analyse in what situations they occur. There are at least two distinctly different types of acute hamstring strains, one occurring during high-speed running and mainly involving the biceps femoris long head, the other during movements leading to extensive lengthening of the hamstrings (such as high kicking, sliding tackle, sagittal split) often involving the free proximal tendon of semimembranosus. These two injury types will be exemplified with injury situations, MRI findings and time back to sport from our ongoing study on acute hamstring strains. When the free proximal tendon is involved, there seems to be an extended period of time before full function without symptoms is reached. Injury type, palpation of maximal pain and MRI findings (tissues involved) can give important information about prognosis.

Prevention It seems to be very important to specifically restore the eccentric hamstring muscle strength after injury before returning to sport to prevent the common hamstring re-injury. Also in the few prospective studies that exist, eccentric training appears to be an essential ingredient. This has been indicated in two rather recent Scandinavian studies, one prospective randomised study on Swedish elite male football players and the other on Icelandic and Norwegian male elite football players. However, both studies suffer from methodological shortcomings, which limit their impact.

Rehabilitation There are no studies describing what kind of rehabilitation programme athletes suffering different types of hamstring strains should perform. One study indicated that core stability training is an important part of the rehabilitation programme. In our ongoing study we randomised the injured athletes into two different programmes. Different exercises with the aim of putting high eccentric demand on the hamstrings in situations with different degrees of lengthening of the hamstring muscle-tendon complex.

Testing There is no consensus about a single test, clinical examination or imaging investigation that would provide strict criteria for safe return to sport following hamstring muscle strain. We are currently evaluating a new active hamstring flexibility test that appears to add discriminative power and provide useful additional information to the common clinical examination before going back to full training/match. Preliminary data will be presented and discussed.