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  • Writer's pictureSachin Bhat

Grading Muscle Injuries

Many recreational, sub-elite, and professional athletes will sustain muscle injuries along the course of their sporting journeys. This may range from hamstring injuries during sprinting, groin injuries whilst playing soccer, calf tears whilst running, and so on. They are common and can present in different ways.

Have you ever wondered why each of these individual injuries can have such different rehabilitation timelines? This is in part due to the specific tissues involved, and the extent to which they are altered when an injury occurs.

As physiotherapists, we use injury grading systems to help stratify these injuries according to which part of the tissue is involved, and the severity of the injury. You may have heard for example, your physiotherapist describe your hamstring strain as a grade 2B biceps femoris strain.

What does this mean? The following information will be in respect to the British Athletics Muscle Injury Classification system (Pollock et al., 2014), which tends to be commonly used and is based on MRI findings. It is worth noting that for most muscular injuries, it is not necessary to obtain an MRI to gauge the extent of the injury.

Grading Muscle Injuries
Grading Muscle Injuries

The number - This is in reference to how much of the total tissue is involved. The higher the number, the more tissue is involved, which typically means a longer return to play time.

● grade 0

● grade 0a: focal neuromuscular injury with normal MRI

● grade 0b: generalized muscle soreness with normal MRI or MRI findings typical of

delayed onset muscle soreness (DOMS)

● grade 1 (mild): high STIR signal that is <10% cross-section or longitudinal length <5 cm with <1

cm fiber disruption

● grade 2 (moderate): high STIR signal that is 10-50% cross-section; longitudinal length 5-15 cm

with <5 cm fibre disruption

● grade 3 (extensive): high STIR signal that is<50% cross-section or longitudinal length <15 cm

with <5 cm fibre disruption

● grade 4: complete tear

The letter - This refers to which part of the muscle is involved. Refer to the image which helps to distinguish this:

A - myofascial

B - myotendinous/musculotendinous junction

C - tendinous/intratendinous

As a general rule of thumb, grade C injuries require notably more time to return due to tendon

involvement. As tendons do not have a rich blood supply like muscular structures do, healing times take longer and require more time to adapt to loading demands. Similarly, higher grade injuries will be initially more debilitating and require longer return to play times to account for the time required to return to previous levels of function.

Return to play times would then be dictated by numerous things, including but not limited to:

● activity

● muscle injured

● extent of injury

● history of previous injury

● strength

and so on.

If you’ve injured a muscle and want to return as quickly, and safely as possible, see a trained

physiotherapist who can help you understand the extent of your injury and help you develop a specific plan to get you to your goals!


Pollock N, James SLJ, Lee JC, et alBritish athletics muscle injury classification: a new grading

systemBritish Journal of Sports Medicine 2014;48:1347-1351.

Knipe, H. (2020, February 13). British Athletics Muscle Injury Classification: Radiology Reference Article.

McAleer, S., Macdonald, B., Lee, J., Zhu, W., Giakoumis, M., Maric, T., Kelly, S., Brown, J., &amp; Pollock, N.

(2022). Time to return to full training and recurrence of rectus femoris injuries in elite track and field

athletes 2010–2019; a 9‐year study using the British Athletics Muscle Injury Classification. Scandinavian

Journal of Medicine &amp;amp; Science in Sports, 32(7), 1109–1118.

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