This is a catchall term for a tear to one of the muscles in the back of the thigh. Whilst some general short-term measures can be considered (i.e. rest, ice, stretches) a more accurate diagnosis is required for specific treatment. The specific muscle involved need to be identified and the severity of the strain can be graded (1-3) dependent upon the percentage of muscle fibres torn.
However, if there is a recurrent injury then this can be due to a problem with the underling biomechanics. If this is the case, a 3-D gait evaluation will help to identify the problem.