Hamstring strains are among the most common injuries in sports, often resulting in prolonged time away from competition and a substantial risk of recurrence. While rehabilitation typically incorporates strengthening, stretching, and progressive functional exercises, the evidence supporting these interventions is not always as strong as we might assume.
A 2026 clinical practice guideline published in the Journal of Orthopaedic & Sports Physical Therapy by Baroni and colleagues evaluated the available evidence for hamstring strain rehabilitation. The findings provide practical recommendations while highlighting significant gaps in our understanding of optimal treatment strategies.
The Study
This clinical practice guideline was developed using the GRADE framework, a standardized method for evaluating evidence quality and developing clinical recommendations.
Researchers reviewed 11 randomized controlled trials involving 551 athletes, examining interventions such as eccentric strengthening, phase-organized rehabilitation, agility and trunk stabilization exercises, stretching, and photobiomodulation.
Interestingly, all six recommendations were supported by evidence rated as either low or very low certainty, reflecting the relatively limited research available.
The Recommendations
1. Phase-organized rehabilitation
The guideline suggests progressing rehabilitation according to objective criteria, including pain, range of motion, strength, and functional performance, rather than time alone. Two small trials suggested potential improvements in strength, function, and recurrence rates, although the optimal progression criteria remain unclear.
Certainty of evidence: Very low.
2. Pain during exercise
Exercises may be performed with pain levels up to 4/10, provided symptoms are monitored and the athlete tolerates the loading. One trial involving 43 athletes found no difference in return-to-sport time or recurrence between pain-free and pain-threshold exercise groups, although greater isometric strength gains occurred in the latter.
Certainty of evidence: Very low.
3. Eccentric strengthening
Eccentric exercises received the strongest support among the interventions evaluated. Two trials involving 131 athletes reported an approximately 28-day earlier return to sport with eccentric-focused rehabilitation compared with conventional exercise programs.
Another trial suggested that eccentric loading could begin within the first week following injury when appropriately monitored and progressed.
Despite these promising results, the optimal exercise selection, intensity, and progression remain uncertain.
Certainty of evidence: Low.
4. Progressive agility and trunk stabilization
Progressive agility and trunk stabilization (PATS) exercises may improve functional outcomes and reduce recurrence risk, although results were inconsistent.
One small trial reported substantially lower reinjury rates with PATS exercises compared with conventional rehabilitation. However, the small sample sizes limit confidence in these findings.
Certainty of evidence: Very low.
5. Static stretching
The guideline found insufficient evidence to recommend routine static stretching. Two trials demonstrated limited or inconsistent effects on pain, function, and return-to-sport time.
Stretching may be appropriate for individual mobility limitations, but its inclusion should not be assumed necessary for every rehabilitation program.
Certainty of evidence: Very low.
6. Photobiomodulation therapy
One trial involving 24 athletes found no significant additional benefits from photobiomodulation when combined with exercise rehabilitation.
The current evidence is insufficient to support its routine use for improving hamstring recovery.
Certainty of evidence: Very low.
Limitations of the Study
Despite the systematic methodology, several limitations deserve consideration.
Limited evidence: Only 11 trials involving 551 athletes were included, with relatively small sample sizes.
High risk of bias: Eight of the 11 trials were classified as having a high risk of bias.
Limited generalizability: Participants were predominantly male competitive athletes, making application to other populations less certain.
Inconsistent protocols: Differences in treatment progression, exercise selection, and outcome measurements complicated comparisons between studies.
Most importantly, none of the recommendations were supported by moderate- or high-certainty evidence.
Clinical Implications
Perhaps the most important takeaway is that many commonly accepted rehabilitation strategies are supported by less robust evidence than we might expect.
Eccentric strengthening appears particularly promising, which makes sense when considering the mechanical demands placed on the hamstrings during running and sprinting.
However, not all eccentric exercises provide equivalent loading. A Nordic hamstring curl, Romanian deadlift, and eccentric slider differ in muscle length, joint angles, moment arms, and resistance demands. Selecting and progressing these exercises should reflect the athlete's impairments and functional goals rather than following a rigid protocol.
The recommendation permitting mild-to-moderate pain during exercise is also clinically relevant. Complete pain avoidance may not always be necessary, provided symptoms remain tolerable and loading is appropriately monitored. However, this should not be interpreted as permission to exercise through progressively worsening symptoms.
Finally, while agility and trunk stabilization exercises may help prepare athletes for the demands of sport, objective progression should remain central to rehabilitation. Restoring isolated hamstring strength alone does not necessarily indicate readiness for sprinting, cutting, or repeated high-intensity efforts.
Final Thoughts
This guideline reinforces that effective rehabilitation does not always require an extensive collection of interventions.
Eccentric strengthening, criteria-based progression, tolerable symptom-guided loading, and functional exercise are reasonable components of hamstring strain rehabilitation. However, the evidence supporting these approaches remains limited, and no single protocol has been established as definitively superior.
Ultimately, rehabilitation should focus on progressively restoring the athlete's capacity to tolerate the mechanical demands of their sport, while accounting for individual symptoms, impairments, and recovery.
At The LAB Doctors of Physical Therapy, our approach to sports injury rehabilitation emphasizes evidence-informed exercise selection, progressive loading, and individualized movement assessment to help athletes return to their activities safely and confidently.
Citations
1.) Baroni BM, Oliveira RR, Pereira ALA, et al. Rehabilitation of athletes with hamstring strain injury: SONAFE-Brazil clinical practice guideline. J Orthop Sports Phys Ther. 2026;56(10):627–641. doi:10.2519/jospt.2026.14372.