This is the muscle injury classification that I generally refer to with expected return to sporting activity:
| GRADE | DESCRIPTION | RETURN TO SPORT |
| 0 | Oedema/fluid around tendon/epimysium | <2 weeks |
| 1 | Myofibril disruption without epimysial or myofascial changes | 1-4 weeks |
| 2 | plus epimysial/myofascial interuption or delamination | 3-6 weeks |
| 3 | intramusculat tendon or epimysial failure/tear | 6+ weeks |
This shows a grade 2 tear of the rectus femoris. Note the showdowing disruption extending from the epimysium into the muscle.