Grading Muscle Injuries

Muscle injury grading is based on imaging and helps us understand how severe the injury is and how long it might take to recover.

Grade guide:

Grade 1 (mild): Small area of injury in the muscle, less than 10% of the muscle size or shorter than 5 cm, with very little tearing of the muscle fibers (less than 1 cm).

Grade 2 (moderate): Moderate injury affecting 10–50% of the muscle or 5–15 cm in length, with some tearing of the muscle fibers (less than 5 cm).

Grade 3 (severe/extensive): Large injury affecting more than half of the muscle or longer than 15 cm, with significant tearing of the muscle fibers (more than 5 cm).

Grade 4: Complete tear of the muscle.

Location of injury:

A: Myofascial (peripheral): Injury at the edge of the muscle.

B: Myotendinous junction / muscular: Injury where the muscle meets the tendon.

C: Tendinous: Injury in the tendon itself.

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Example:

A Grade 3c hamstring injury indicates a large tear at the hamstring tendon. In general, the higher the grade and letter, the longer the recovery time.