What Is a Muscle Strain?

You felt something pull, and now you want to know whether that is a muscle strain and how serious it is.

What a muscle strain is

A muscle strain is a tear in the muscle fibers. Cleveland Clinic says: "A muscle strain, or pulled muscle, is a tear in your muscle fibers." It also notes that "Muscle strains can be mild to severe."

What separates a mild strain from a severe one

The grade tells you how much of the muscle has torn. Cleveland Clinic describes it this way: "A grade 1 muscle strain only pulls and breaks a few fibers. But a grade 3 muscle strain tears all the way through."

Strains also come from two familiar causes. According to Cleveland Clinic, "You can strain a muscle by pulling it too hard or using it too much, which weakens the fibers."

Cleveland Clinic adds: "It’s one of the most common soft tissue injuries." A common injury still deserves a clear standard for when it counts as finished.

What to read before you return to activity

Match your own symptoms against a published description. Cleveland Clinic's page on a torn calf muscle covers causes, symptoms and treatment for one common site. Its page on sprains is a companion read.

Then write down what should be true before you go back to running, work or lifting. If your symptoms look more like the severe end of the grades, take that list to a clinician.

Why the grade matters

A mild strain and a severe one need different benchmarks. Start by finding out where your injury sits on the grades.