Hamstring strain injuries are among athletes’ most common soft tissue injuries, especially in sports requiring high-speed running, such as football, soccer, and track events. A hamstring strain occurs when the muscle fibres are overstretched or torn, often resulting in pain, weakness, and limited function. These injuries can significantly impact athletic performance and increase the risk of long-term complications if not managed correctly. This blog provides an in-depth, evidence-based overview of hamstring strains, grounded exclusively in findings from peer-reviewed research literature. We’ll explore risk factors, rehabilitation strategies, return-to-play (RTP) criteria, and proven prevention methods to help athletes, clinicians, and coaches make informed decisions.
In July 2023, England footballer Reece James suffered a hamstring strain during a pre-season match, drawing media attention to the recurring issue of soft tissue injuries in elite athletes. The incident led to weeks of rehabilitation and raised questions about injury prevention protocols in high-performance environments. James’ case is not unique—it underscores how common and disruptive these injuries can be, even for top-tier athletes with access to state-of-the-art medical care.
What Causes a Hamstring Strain Injury?
The hamstring muscle group, consisting of the biceps femoris, semitendinosus, and semimembranosus, plays a critical role in hip extension and knee flexion. Hamstring injuries most frequently occur during the terminal swing phase of sprinting, when the muscles eccentrically contract to decelerate the extending knee. This high mechanical load, especially in a lengthened position, significantly increases the risk of a hamstring strain.
A systematic review by Green et al. (2020) identified two of the most significant non-modifiable risk factors: previous hamstring injury and advancing age. Prior injury increases the likelihood of reinjury by approximately 2.7 times. Modifiable risk factors also play a key role. According to Mendiguchia et al. (2012), these include deficits in eccentric hamstring strength, poor lumbopelvic control, and limited flexibility—though evidence for flexibility as an isolated risk factor remains mixed.
Hamstring Strain Rehabilitation: What Does the Research Say?
Rehabilitation after a hamstring injury should be tailored to the individual, following a criterion-based progression rather than a one-size-fits-all time-based protocol. Eccentric strengthening, particularly at longer muscle lengths, has emerged as a cornerstone of effective hamstring strain rehabilitation. This individualized approach is crucial in addressing each patient’s unique needs and ensuring a successful recovery.
A study by Bourne et al. (2022) emphasized that exercises targeting eccentric strength, such as the Nordic Hamstring Exercise (NHE), improve muscle architecture by increasing fascicle length and enhancing the muscle’s ability to tolerate high loads. Eccentric training also helps address neuromuscular deficits that commonly follow injury.
Rehabilitation protocols should initially include pain-free range-of-motion and isometric exercises. As recovery progresses, isotonic and eccentric exercises should be introduced with gradually increased load and movement range. Functional tasks and sport-specific drills are integrated in the later stages. High-speed running should be reintroduced before RTP to ensure readiness for game conditions.
Return-to-Play After a Hamstring Injury: Criteria and Guidelines
One of the ongoing challenges in hamstring rehabilitation is determining when an athlete is ready to return to play. A systematic review by Tol et al. (2014) highlighted the wide variability in RTP criteria and the lack of standardized assessment protocols.
Despite this variability, several widely accepted RTP benchmarks include:
- Full, pain-free range of motion
- Eccentric strength of the injured limb within 10% of the contralateral side
- Ability to sprint and perform sport-specific drills at maximal effort without symptoms
- Clearance from a medical professional
Objective assessment tools, such as isokinetic strength testing and functional performance evaluations, are increasingly advocated to improve RTP decisions and reduce the risk of re-injury.
Hamstring Injury Prevention: Role of the Nordic Hamstring Exercise
Preventing hamstring strain injuries is a top priority in sports medicine due to the high recurrence rate. Among the most effective evidence-based prevention strategies is the Nordic Hamstring Exercise (NHE).
A systematic review and meta-analysis by van Dyk et al. (2019) found that incorporating the NHE into training programs reduced hamstring injury rates by up to 51%. Despite this strong evidence, many teams still struggle with poor compliance and low adherence to NHE protocols.
The NHE stands out for its simplicity, minimal equipment needs, and substantial impact on eccentric strength development and fascicle lengthening. Integrating the NHE into team warm-ups and conditioning programs can significantly reduce the incidence of hamstring injuries across various sports.
Conclusion: Evidence-Based Management of Hamstring Strains
Hamstring strains are complex injuries influenced by both modifiable and non-modifiable risk factors. An evidence-based approach to rehabilitation—emphasizing eccentric loading, functional progression, and individualized RTP criteria—can enhance outcomes and reduce recurrence rates. Preventive strategies, including the Nordic Hamstring Exercise, offer a scientifically validated method to reduce hamstring strain incidence.
Athletes, coaches, and clinicians should commit to implementing and maintaining these research-supported practices to promote long-term muscle health and sustained athletic performance.
References
Bourne, M. N., Williams, M. D., Opar, D. A., Al Najjar, A., Kerr, G. K., & Shield, A. J. (2017). Impact of exercise selection on hamstring muscle activation. Br J Sports Med, 51(13), 1021-1028. https://doi.org/10.1136/bjsports-2015-095739
Green, B., Bourne, M. N., & Pizzari, T. (2018). Isokinetic strength assessment offers limited predictive validity for hamstring strain injury in sport: A systematic review and meta-analysis. Br J Sports Med, 52(5), 329-336. https://doi.org/10.1136/bjsports-2017-098101
Mendiguchia, J., Brughelli, M., & Alentorn-Geli E. (2012). Hamstring strain injuries: Are we heading in the right direction? Br J Sports Med, 46(2), 81-85. https://doi.org/10.1136/bjsm.2010.081695
van Dyk, N., Behan, F. P., & Whiteley, R. (2019). Including the Nordic hamstring exercise in injury prevention programmes halves the rate of hamstring injuries: A systematic review and meta-analysis of 8459 athletes. British Journal of Sports Medicine, 53(21), 1362–1370. https://doi.org/10.1136/bjsports-2018-100045