Muscle injuries: 2020 update of the I.S.Mu.L.T. classification

It is becoming increasingly important to have a common terminology, as international and shared as possible, beginning with the classification of injuries. This can then aid in correct diagnosis, a focus prognosis, and appropriate therapy. The most adopted classification system within practice must thus be both accurate and complete but also clinically useful for those less familiar in injury management. Muscle injuries are divided into two main categories according to the mechanism of onset: direct muscle injuries caused by the impact of a blunt body against the muscular belly and in indirect muscle injuries, caused by a phenomenon of overstretching or eccentric contraction causing internal disruption on the muscle-tendon unit. For the clinician who faces these pathologies, it is essential to utilize a classification system which considers both the clinical findings and information from diagnostic investigations, such as ultrasound and MRI. The multi-modal approach to muscle injury assessment (clinical, ultrasound and possibly resonance imaging) seems essential for a correct clinical framework and the assessment of the severity of injury, to subsequently determine the most appropriate therapeutic pathway. In recent years, numerous classifications have been published, to attempt to arrive at a standardized common language, but in most cases it has failed to make all the professional figures involved in the dialogue on rehabilitation. For an appropriate classification system, it is important to adopt correct terminology and avoid terms such as ‘elongation’ or ‘strain’. The objective of this paper is not to deeply address the diagnostic and therapeutic approach of muscle injuries, but to renew the standard scientific language related to muscle injuries among the various professional figures involved in rehabilitation starting from the already shared I.S.Mu.L.T. 2014 muscle injuries classification.