We get asked this question quite a lot. It's a good question, and surprisingly Wikipedia doesn't even have the correct answer! (if you can believe such a thing).
What Makes a Muscle Tear?
Muscles generally tear, not from being stretched too far, but from being placed under too much eccentric load. What does that mean? It means they are being lengthened while working to control that movement. For example your hamstrings work eccentrically while your leg is swinging during running and kicking, and it is these movements that often cause hamstring tears to occur.
What can be quite annoying and confusing is that there doesn't need to be anything special about the time you're doing a particular activity when you tear a muscle. It's more a build up of force over time and when the muscle tears it's the straw that broke the camel's back.
What Puts You At Greater Risk of a Muscle Tear?
There are some risk factors which increase your chance of suffering a muscle tear, such as
- Having previously injured that muscle
- Fatigue
- Inadequate warmup
- Muscle imbalances (such as weakness of the affected muscle or of muscles that would otherwise reduce the load on that muscle)
How Long Will It Take To Heal?
Muscles have a good blood supply and so they usually heal quite well, provided the injury isn't actually to the tendon portion of the muscle.
The length of recovery is dependent mainly upon the degree to which the muscle is torn. Smaller muscle tears may only take a few weeks to recover to the point you can return to sport, while large muscle tears may take two or three months.
What Can Physios Do For a Muscle Tear?
Initially a physio can provide treatment to assist in pain relief and reduction of inflammation during the acute inflammatory phase of healing.
As you progress, your physio will guide you through a rehab program focused on strengthening the muscle to make it better able to deal with eccentric loads, lengthening the muscle and correcting any other biomechanical issues which may be placing the muscle under increased load.