How early should you start rehabilitation following a muscle strain injury?

It used to be thought that waiting to start rehabilitation on a muscle strain injury would improve the outcomes and reduce the likelihood of having a re-injury of the same muscle.  However research is starting to show that early intervention and loading reduces the time for return to activity, and does not add to increasing the likelihood of re-injuring the same strain.  

This is a question that often gets asked in clinic or when dealing with athletes in the sporting setting, ‘When should I start loading my hamstring, calf, quad following a strain injury?’  Research is starting to shed some light on these questions. Research by Bayer et al 2017, in amateur athletes showed that starting rehabilitation at 2 days post injury, compared with 9 days post injury, significantly reduced the time to returning to sport. This is something that we see daily in clinic also. When patients come in for rehabilitation, but have waited before starting they often have extended return to sport periods.

Why is this?

The body and particularly soft tissue structures (muscle, tendon, connective tissue) adapt through a process termed mechanotransduction. What this means is that mechanical loading (physical activity that places force through the tissue) is the signal for the tissue to adapt. Adaptation in this setting means laying down more muscle fibre volume, increasing the size, length or shape of the muscle fibres to increase the tissues ability to deal with the stress that has been placed upon that tissue.

Conversely doing no loading (resting or immobilising the injury for extended periods) sends the signal to reduce the tissue in size or volume, essentially the lack of loading sends the message that the tissue is not required.  

So when should you start loading following muscle strain injury?  Probably sooner than you think.