Understanding Hamstring Strains & Injury: Rehabilitation and Prevention for Optimal Performance

Hamstring strains frequently afflict athletes engaged in explosive sports like football, AFL, athletics, and rugby due to the demands of high-speed running and sudden explosive accelerations. In this piece, we delve into the anatomy and mechanisms behind hamstring strain injuries, their rehabilitation nuances, and proactive measures to mitigate future risks.

Anatomy & Injury Mechanisms

The hamstrings, crucial in knee flexion and hip extension during movement, comprise the Semitendinosus, Semimembranosus, and Biceps Femoris muscles. During running, they act as antagonists to the anterior quadriceps muscles, functioning eccentrically to decelerate knee extension to protect the knee and enhance run gait function and efficiency.

Injuries typically occur during sprinting (including accelerations), high-intensity decelerations, or stretch-based motions like kicking.

1. Sprinting based injuries: typically occurring during the terminal swing phase of gait when maximal eccentric hamstring contraction occurs. The early stance phase and swing-stance transition period has also been reported as gait cycles whereby injury may occur, with different loading mechanisms contributing to injury.
2. High intensity decelerations: an often overlooked mechanism whereby braking strategies where knee is extending and the trunk is flexed, causing increased eccentric ‘stretch’ hamstring forces
3. Stretch based injuries: typically occur when excessive, sudden stretch occurs, involving extensive hip flexion and simultaneous knee extension. Typically seen with kicking related injuries in sports such as football and AFL

What are the Injury Risk Factors?

Numerous intrinsic and extrinsic factors influence hamstring strain risks, including age, sex, body composition, previous injuries, joint mechanics, strength, endurance, and acute/chronic loading. While some factors are unchangeable, focusing on modifiable aspects like fascicle length, eccentric strength and tendon reactive qualities can mitigate injury risk.

Rehabilitation - Optimising Return to Performance

When reconditioning following hamstring injury, we must consider 3 key questions:

1. What are the tissue-specific considerations to return to performance?
2. What are the sport-specific considerations to return to performance?
3. And how do we combine these two, along with the global, holistic factors of the individual required for elite performance?

Lets consider the tissue-specific considerations for return to performance following a grade 2b biceps femoris long head muscle strain for instance. Evidence highlights that:

• Biceps Femoris action is hip dominant so focusing hip dominant exercises such as Romanian deadlifts, GHD hip extensions & conic pulley variations provide specificity. This differs to medial hamstring muscles (Semimembranosus and Semitendinosus) where they are knee dominant in nature.
• Biceps femoris long head demands are greatest during the leg deceleration and foot strike activities when eccentric-concentric muscle transition occurs, requiring significant eccentric strength
• It also experiences the greatest eccentric lengthening during this phase (110% of standing length), highlighting the importance of increasing fascicle length. This influences exercises selection and program periodisation.

Other factors that are also important to address during the rehabilitation process include:

• Lumbopelvic control
• Running mechanics
• Synergist and antagonist musculature
• Tendon stiffness

We then need to consider what activity/sport is this individual returning to? No two hamstring injuries are the same. An individual who injures their hamstring whilst kicking during AFL (stretch mechanism) has different return to performance requirements to an individual who competes track sprinting. This is important, especially during latter phases of reconditioning whereby specificity is crucial to allow return to elite performance.

By having an understanding of the outcome we are aiming towards (need analysis) and what elite performance looks like for an individual, we can then ‘work backwards’ to design an appropriate, specific and progressive rehabilitation plan.

A final important note regarding the rehabilitation process, is that it is crucial to ensure appropriate, key objective test measures are achieved prior to progression. “When can I run?” & “When can I return to my sport” are questions I always get asked during the rehabilitation process. Historically, time-based criteria was used during musculoskeletal rehabilitation (i.e., once you hit for example 6 weeks post injury, you were ready to return to sport). This model however, is outdated. Although timeframes provide us with a good indication of how long rehabilitation will take (and are important to respect especially for tendon-based & surgical injuries), objective-based criteria should be used. This involves setting appropriate objective markers for each stage of rehabilitation which provides us with the evidence that your hamstring is ready to progress to the next stage. Such objective criteria for hamstring rehabilitation includes: symptoms, clinical assessment tests, gym-based physical tests and pitch/grass based tests, along with consideration for acute:chronic loading and mechanism specific criteria (e.g. can I sprint maximally & repeatedly). Psychosocial factors are also important to utilise as part of the decision making process for return to performance.

Strategies for Preventing Hamstring Strains

Preventing recurring hamstring injuries involves implementing a comprehensive approach. Key factors include:

• Adequate warm up/cool down routine
• Hamstring strengthening program to address weakness and modifiable risk factors
• Monitoring of training and game loads and minimising ‘spikes’ in loading
• Ensuring adequate exposure to mechanisms - sprinting, acceleration/decelerations and kicking. This serves to act as a ‘vaccine’ to reduce injury risk
• Addressing kinematic and biomechanical factors that may overload the hamstrings. For instance, are the lumbopelvic factors (anterior pelvic tilt) that are increasing the load to the proximal hamstrings unfavorably?
• Develop fatigue resistance and monitoring hamstring fatigue
  

To Finish

Hamstring strains are prevalent in explosive sports, demanding varied recovery times. Rehabilitation strategies should encompass tissue-specific and sport-specific approaches, employing objective-based criteria and testing for progress. Implementing preventive measures can substantially reduce the risk of future injuries, ensuring athletes return to their sport in prime condition.

If you are experiencing hamstring pain/injury or are looking to obtain objective data on your hamstring strength and function, consider a physiotherapy or testing & screening consultation for individualised, tailored guidance. Your journey to successful return to performance starts here 💫 💪

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References

Woods, C., Hawkins, R., Maltby, S., Hulse, M., Thomas, A., & Hodson, A. (2004). The Football Association Medical Research Programme: An Audit of Injuries in Professional Football - Analysis of Hamstring Injuries. British Journal of Sports Medicine.

Yu, B., Liu, H., & Garrett, W. (2017). Mechanism of hamstring muscle strain injury in sprinting. Journal of Sport and Health Science, 130-132.

Timmins, R., Bourne, M., Shield, A., Williams, M., Lorenzen, C., & Opar, D. (2016). Short Bicep Femoris Fascicles and Eccentric Knee FLexor Weakness Increase the Risk of Hamstring Injury in Elite Football (Soccer): A Prospective Cohort Study. British Journal of Sports Medicine , 1524-1535.

Shield, A., & Bourne, M. (2018). Hamstring Injury Prevention Practices in Elite Sport: Evidence for Eccentric Strength vs. Lumbo-Pelvic Training. Sports Medicine , 513-524.

Opar, D., Williams, M., & Shield, A. (2012). Hamstring Strain Injuries. Sports Medicine, 209-226.

Danielsson, A., Horvath, A., Senorski, C., Eduard Alentorn-Geli, Garrett, W. E., Ramón Cugat, … Eric Hamrin Senorski. (2020). The mechanism of hamstring injuries – a systematic review. 21(1). https://doi.org/10.1186/s12891-020-03658-8

Huygaerts, S., Cos, F., Cohen, D., Calleja-González, J., Guitart, M., Blazevich, A. J., & Alcaraz, P. E. (2020). Mechanisms of Hamstring Strain Injury: Interactions between Fatigue, Muscle Activation and Function. 8(5), 65–65. https://doi.org/10.3390/sports8050065

McBurnie, A., Harper, D., Jones, P. A., & Dos’Santos, T. (2021). Deceleration Training in Team Sports: Another Potential “Vaccine” for Sports-Related Injury? 52(1), 1–12. https://doi.org/10.1007/s40279-021-01583-x

Erickson, L. O., & Sherry, M. A. (2017). Rehabilitation and return to sport after hamstring strain injury. 6(3), 262–270. https://doi.org/10.1016/j.jshs.2017.04.001

Hickey, J. T., Timmins, R. G., Maniar, N., Williams, M. D., & Opar, D. A. (2016). Criteria for Progressing Rehabilitation and Determining Return-to-Play Clearance Following Hamstring Strain Injury: A Systematic Review. 47(7), 1375–1387. https://doi.org/10.1007/s40279-016-0667-x

Hickey, J. T., Opar, D. A., Weiss, L., & Heiderscheit, B. C. (2021). Hamstring Strain Injury Rehabilitation. 57(2), 125–135. https://doi.org/10.4085/1062-6050-0707.20

Kellis, E., & Chrysostomos Sahinis. (2022). Is Muscle Architecture Different in Athletes with a Previous Hamstring Strain? A Systematic Review and Meta-Analysis. 7(1), 16–16. https://doi.org/10.3390/jfmk7010016

Disclaimer: This blog is for informational purposes and should not be considered a substitute for professional medical advice. Please consult with our qualified healthcare providers for personalised recommendations related to your specific condition and needs.

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