I often receive this question from aspiring sports trainers.

✅Q: What are the criteria for deciding when to return to play after a hamstring strain?

✅A: For the past few years, we have been incorporating ultrasound evaluation in our decision-making process for return to play.

⚫️Case: Hamstring Strain in a Soccer Player

・Soccer player
・Proximal hamstring strain (diagnosed by a physician)
・Injury at the muscle-tendon junction of the long head of the biceps femoris (BFlh) and the conjoint tendon (CT)

⚫️Ultrasound Observation at 4 Weeks

・Prone position with slight knee flexion
・Isometric contraction
・Ultrasound observation shows that the (red circle) area does not appear to move as a single unit.

⚫️Physical Examination Findings

・Forward bending: no difference in hamstring stretch pain between the left and right sides
・Straight Leg Raise (SLR) test: no pain
・Hip flexion with knee extension: stretch pain present
・Hip flexion with knee extension followed by knee flexion: reduced strength and some discomfort

⚫️Evaluation (Including Physician's Diagnosis)

It is assessed that the muscle and tendon have not adequately healed. Sprinting is prohibited, and the patient is advised to progress gradually through jogging, strength training, agility drills, and sport-specific training. Although the patient hoped to return to play at 6 weeks, the current evaluation indicates a high risk of re-injury.

⚫️What if There Was No Ultrasound Evaluation?

Initially, I thought it might be possible to return at 6 weeks. The initial pain at 4 weeks has already subsided. However, based on the reduction in stretch pain and pain during muscle contraction, the decision would have still been that returning at 6 weeks carries a high risk even without the ultrasound evaluation.

The ultrasound provided additional evidence to support this decision.

⚫️Communicating with the Athlete

The presence of the ultrasound evaluation changes the nuance when communicating with the athlete.

This decision might seem ambiguous or different in some way. However, after making RTP (Return to Play) decisions for many years, it is often challenging to make a clear-cut judgment. Nine out of ten athletes return without issues.
However, some athletes experience recurrent injuries. To prevent this, continuous research is necessary.

⚫️Reasons for Recurrence of Hamstring Strains

Returning to play solely because the pain has subsided is believed to increase the risk of recurrence. Ultrasound images are difficult to reproduce, and the non-unified movement observed may still require further research to understand the underlying tissue structure.

However, viewing ultrasound images showing non-unified movement:

・It seems that if movement is forced, the tissue will not heal.
・Unhealed tissue is likely to re-injure.
・Is this the last chance to properly heal the initial strain? (Proper healing of the initial strain is crucial).

⚫️Criteria for Returning to Play After a Hamstring Strain

My criteria for returning after a hamstring strain are:

These criteria are used to make the decision.