Hamstring strain

A sudden pain in the back of your thigh while sprinting. You may have pulled a hamstring, one of the most common muscle injuries among athletes. This injury accounts for 37% of muscle injuries in professional soccer¹ and affects both amateur and professional athletes alike.

Good news: With the right treatment and proper rehabilitation, most people are able to resume their normal activities. Here’s what you need to know to recover successfully.

What is a Hamstring Strain?

A hamstring strain is a tear in the muscle fibers at the back of the thigh, affecting one or more of the three muscles that make up this group: the biceps femoris, semitendinosus, and semimembranosus.

The hamstrings are made up of three distinct muscles. The biceps femoris is located on the outer side of the thigh, while the semitendinosus and semimembranosus are on the inner side.

The biceps femoris is the most commonly affected muscle: its long head is involved in 70% of injuries seen on MRI². These injuries typically occur at the myotendinous junction, where the muscle meets the tendon².

The hamstrings play an essential role: they bend the knee, extend the hip, and stabilize the pelvis during running.

What Causes a Hamstring Strain?

At the end of the leg's swing during running, the hamstrings are stretched the most while contracting to slow the leg down, which could explain the strain⁵.

This phase occurs just before the foot touches the ground during a sprint⁵.

A meta-analysis published in the British Journal of Sports Medicine identifies the following risk factors:

In professional soccer, injuries are more common toward the end of each half⁷.

Several factors increase the risk of a hamstring strain: older age, a previous hamstring injury, reduced flexibility in the quadriceps and hip flexors, and fatigue⁵.

Hamstring strains are particularly common in sports that involve sprinting, accelerating, braking, changing direction quickly, and jumping⁸, such as track and field, soccer, American football, and dance.

Who is at Risk of a Hamstring Strain?

Advanced age and a previous muscle strain are the two strongest risk factors for muscle strain⁶. A significant proportion of hamstring strains recur within the first year after returning to sports, and the recurrence is often more severe than the initial injury⁵.

In men's professional soccer, there is slightly more than one hamstring injury per 1,000 hours of training and competition⁹. Players who have previously suffered a hamstring strain are particularly vulnerable⁶.

That is why a comprehensive rehabilitation program before returning to sports is essential.

How to Recognize the Symptoms of a Hamstring Strain?

The main symptom is a sudden, localized pain in the back of the thigh, sometimes accompanied by a popping sensation at the moment of injury¹⁰.

After a muscle strain, putting weight on the leg is painful, and you walk with a stiff leg to avoid bending the hip and knee¹¹.

• Palpation of a specific tender point on the back of the thigh¹⁰
• Active Knee Extension Test: Pain-Induced Limitation¹²
• Passive Stretch Test: Pain During Muscle Elongation¹²
• Isometric Strength Test: Weakness and Pain¹²

• A palpable depression in the muscle (suggesting a tear)¹¹¹³
• Persistent severe pain even at rest

A few days after an injury near the buttock, a bruise may appear on the buttock and the back of the thigh, extending down the leg¹¹.

What are the different grades of severity?

Commonly used scales have three grades: minor, moderate, or complete injury¹³ (see the explanation of muscle injury grades). The British Athletics Muscle Injury classification, on the other hand, uses grades from 0 to 4, based on MRI findings¹³ :

Surgery is typically considered in cases of a complete rupture, especially when the tendon is torn near the buttock: early surgery yields better results in such cases¹¹.

Grade 3 injuries and those that involve the tendon require more time before returning to training, while Grade 0 injuries require less time¹⁴. The actual recovery time varies greatly from person to person.

Two factors worsen the prognosis: a proximal location (near the buttock) and involvement of the tendon rather than the muscle³¹⁴.

How to treat a hamstring strain?

The treatment follows the PEACE and LOVE principles¹⁵ : We protect the thigh during the first few days, then gradually reintroduce stress to the muscle. Our article on the PEACE and LOVE steps after a sprain or strain explains each letter.

Clinically, it is common to progress through the stages of rehabilitation: isometric, concentric, eccentric, and sport-specific.

The Nordic hamstring exercise reduces the risk of injury by up to 51%¹⁶. Askling’s Protocol L allows for a faster return to sports than conventional approaches¹⁷.

• Among the criteria for returning to play identified by experts are: regaining full strength and flexibility in the hamstrings relative to the healthy side, and no longer experiencing pain in the muscle¹⁸.
• No pain upon palpation

Other benchmarks, such as jump tests and confidence in playing again, apply to all injuries: our article on the criteria and steps for returning to sports after an injury goes into detail about them.

How long does recovery take?

Recovery time varies greatly from person to person. The time it takes for a person to walk without pain helps predict how long it will take to return to sports¹⁹. A previous injury, on the other hand, increases the risk of a relapse. These guidelines should be part of the clinical evaluation¹⁹.

In professional soccer, a hamstring injury can keep a player out of the game for a variable period of time. Returning to the sport too soon increases the risk of a recurrence.

Thigh rehabilitation exercises proceed in four phases, from protection to a return to activities.

How to prevent recurrence?

Prevention relies on eccentric strengthening of the hamstrings. Nordic walking, a form of eccentric hamstring strengthening, helps reduce the risk of injury¹⁶.

The rest of the preventive measures apply to all muscles: a proper warm-up and a training load that increases gradually. Our article on how to pace your effort to avoid overuse injuries provides guidelines, and our article on preventing muscle pain covers warm-ups and stretching.

• Maintain a good balance of strength between the hamstrings and quadriceps
• Do not neglect pre-season training to develop eccentric strength

Key takeaways

• Hamstring strains are common but treatable injuries
• Advanced age and a previous muscle strain are the two strongest risk factors for muscle strain⁶
• The PEACE and LOVE protocol guides modern treatment¹⁵
• Returning to sport should be based on objective criteria, not a fixed timeline

References

1. Ekstrand J, Hägglund M, Waldén M. Epidemiology of muscle injuries in professional soccer. Am J Sports Med. 2011;39(6):1226-32. ↩ Back to text
2. Grange S, Reurink G, Nguyen AQ, Riviera-Navarro C, Foschia C, Croisille P, et al. Location of Hamstring Injuries Based on Magnetic Resonance Imaging: A Systematic Review. Sports Health. 2023;15(1):111-123. ↩ Back to text: 1st, 2nd citations
3. Askling CM, Tengvar M, Saartok T, Thorstensson A. Acute first-time hamstring strains during high-speed running: a longitudinal study including clinical and magnetic resonance imaging findings. Am J Sports Med. 2007;35(2):197-206. ↩ Back to text: 1st, 2nd citations
4. Askling CM, Tengvar M, Saartok T, Thorstensson A. Acute first-time hamstring strains during slow-speed stretching: clinical, magnetic resonance imaging, and recovery characteristics. Am J Sports Med. 2007;35(10):1716-24. ↩ Back to text: 1st, 2nd citations
5. Erickson LN, Sherry MA. Rehabilitation and return to sport after a hamstring strain. J Sport Health Sci. 2017;6(3):262-270. ↩ Back to text: 1st, 2nd, 3rd, 4th references
6. Green B, Bourne MN, van Dyk N, Pizzari T. Recalibrating the risk of hamstring strain injury (HSI): A 2020 systematic review and meta-analysis of risk factors for initial and recurrent hamstring strain injury in sport. Br J Sports Med. 2020;54(18):1081-1088. ↩ Back to text: 1st, 2nd, 3rd, 4th, 5th, 6th citations
7. Woods C, Hawkins RD, Maltby S, Hulse M, Thomas A, Hodson A. The Football Association Medical Research Program: An Audit of Injuries in Professional Soccer—Analysis of Hamstring Injuries. Br J Sports Med. 2004;38(1):36-41. ↩ Back to text
8. Freckleton G, Pizzari T. Risk factors for hamstring muscle strain injuries in sports: a systematic review and meta-analysis. Br J Sports Med. 2013;47(6):351-8. ↩ Back to text
9. Ekstrand J, Waldén M, Hägglund M. Hamstring injuries have increased by 4% annually in men’s professional soccer since 2001: a 13-year longitudinal analysis of the UEFA Elite Club Injury Study. Br J Sports Med. 2016;50(12):731-7. ↩ Back to text
10. Hickey JT, Opar DA, Weiss LJ, Heiderscheit BC. Rehabilitation of Hamstring Strain Injuries. J Athl Train. 2022;57(2):125-135. ↩ Back to text: 1st, 2nd citations
11. Poudel B, Pandey S. Hamstring Injury. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023. ↩ Back to text: 1st, 2nd, 3rd, 4th, 5th, 6th references
12. Heiderscheit BC, Sherry MA, Silder A, Chumanov ES, Thelen DG. Hamstring strain injuries: recommendations for diagnosis, rehabilitation, and injury prevention. J Orthop Sports Phys Ther. 2010;40(2):67-81. ↩ Back to text: 1st, 2nd, 3rd citations
13. Pollock N, James SL, Lee JC, Chakraverty R. British Athletics Muscle Injury Classification: A New Grading System. Br J Sports Med. 2014;48(18):1347-51. ↩ Back to text: 1st, 2nd, 3rd honors
14. Pollock N, Patel A, Chakraverty J, Suokas A, James SL, Chakraverty R. The time to return to full training is delayed and the recurrence rate is higher in acute intratendinous (“c”) hamstring injuries among elite track and field athletes: clinical application of the British Athletics Muscle Injury Classification. Br J Sports Med. 2016;50(5):305-10. ↩ Back to text: 1st, 2nd citations
15. Dubois B, Esculier JF. Soft-tissue injuries simply need PEACE and LOVE. Br J Sports Med. 2020;54(2):72-73. ↩ Back to text: 1st, 2nd citations
16. van Dyk N, Behan FP, Whiteley R. Including the Nordic hamstring exercise in injury prevention programs halves the rate of hamstring injuries: a systematic review and meta-analysis of 8,459 athletes. Br J Sports Med. 2019;53(21):1362-1370. ↩ Back to text: 1st, 2nd, 3rd citations
17. Askling CM, Tengvar M, Thorstensson A. Acute hamstring injuries in Swedish elite soccer: a prospective randomized controlled clinical trial comparing two rehabilitation protocols. Br J Sports Med. 2013;47(15):953-9. ↩ Back to text
18. Zambaldi M, Beasley I, Rushton A. Return-to-play criteria after hamstring injury in professional soccer: a Delphi consensus study. Br J Sports Med. 2017;51(16):1221-1226. ↩ Back to text
19. Warren P, Gabbe BJ, Schneider-Kolsky M, Bennell KL. Clinical predictors of time to return to competition and of recurrence following hamstring strain in elite Australian footballers. Br J Sports Med. 2010;44(6):415-9. ↩ Back to text: 1st, 2nd citations
20. Petersen J, Thorborg K, Nielsen MB, Budtz-Jørgensen E, Hölmich P. Preventive effect of eccentric training on acute hamstring injuries in men's soccer: a cluster-randomized controlled trial. Am J Sports Med. 2011;39(11):2296-303. ↩ Back to text
21. Timmins RG, Bourne MN, Shield AJ, Williams MD, Lorenzen C, Opar DA. Short biceps femoris fascicles and eccentric knee flexor weakness increase the risk of hamstring injury in elite soccer: a prospective cohort study. Br J Sports Med. 2016;50(24):1524-1535. ↩ Back to text

Our physical therapists defined the research strategy, plan, and clinical content of this article. An AI tool assisted with the literature review and text editing to ensure consistency in content and writing style.