What are Hamstring Strains?
Hamstring strains are among the most common musculoskeletal injuries, especially among athletes, characterized by damage to the muscles at the back of the thigh. Hamstrings are particularly injured in sports involving high-speed running, jumping, or sudden directional changes. Understanding the anatomy, grading, symptoms and treatment of hamstring strains is essential for effective management and recovery.1,2
HAMSTRING ANATOMY
The hamstring comprises of 3 muscles located at the back of the thigh:
Biceps Femoris: Located laterally (outside) on the back of the thigh and two heads (long and short). It is the most common hamstring that is injured.
Semitendinosus: Situated medially (inside) on the back of the thigh.
Semimembranosus: Also located medially (inside).
All of the hamstring muscles are primarily responsible for knee flexion (bending) and hip extension which is an important movement for running and walking. The hamstrings originate from the ischial tuberosity of the pelvis and insert into the tibia and fibula in the lower leg, innervated by the sciatic nerve.1,2
HAMSTRING STRAIN GRADES
Hamstring strains are classified into three grades based on severity:
Grade 1 (Mild): A minor strain with minimal tearing of muscle fibres. Symptoms include tightness and slight discomfort during movement. Recovery typically occurs within a few weeks.
Grade 2 (Moderate): A partial tear of the muscle fibres. Symptoms include sharp pain, swelling, and reduced strength. Recovery may take several weeks to a few months.
Grade 3 (Severe): A complete tear or rupture of the muscle. Symptoms include sudden severe pain, swelling, bruising, and an inability to bear weight. Recovery can take several months and may require surgical intervention.
Avulsion fractures may also occur where the hamstring tendon tears away part of the ischial tuberosity, resulting in a loose fragment of bone. These are less commonly injured and generally occur in younger patients who are more skeletally immature.3,4
SIGNS AND SYMPTOMS
Common indicators of a hamstring strain include:
Sudden Pain: Sharp pain at the back of the thigh during physical activity.
Swelling and Bruising: Notable swelling and discoloration may develop within hours to days post-injury.
Muscle Weakness: Decreased strength in the affected leg with some difficulty weight bearing, causing a limp.
Limited Mobility: Difficulty in straightening the knee or bringing the knee towards the chest, flexing the hip.
Tenderness: pain on palpation of the muscle and when stretching the muscle
TREATMENT:
Management of hamstring strains involves several steps:
Immediate Care:
Rest: Cease activities that exacerbate pain to prevent further injury.
Ice: Apply ice packs to the affected area for 15-20 minutes every 2-3 hours during the initial 48 hours to reduce swelling.
Compression: Use an elastic bandage to minimise swelling.
Elevation: Keep the leg elevated above heart level to decrease swelling.
Avoid anti-inflammatories: initially during the period to allow the body to heal itself
Early Mobilisation: Controlled range-of-motion exercises to prevent stiffness.
Rehabilitation:
Physical Therapy: Engage in a structured program focusing on gentle mobility of the hamstring and strengthening exercises to restore flexibility and muscle function.
Strengthening: Exercises to strengthen the hamstrings are important to overcome the weak point in the muscle where the strain occurred. Starting the strengthening with some isometric contractions of the hamstring and then working on the strength through range of motion is important. This will also assist in reducing the risk of another hamstring strain on the same or opposite leg.5
Neuromuscular Training: Incorporating exercises to improve proprioception and dynamic stability. This will help with the pelvic and core control of the upper body and hips which can influence the hamstrings.
Higher Level Strength: working on the strength of the hamstring quickly through the whole length is vital to allow the hamstring to respond to the demands placed on during activities such as running.5
Gradual Return to Activity: Slowly reintroduce physical activities, ensuring the absence of pain or discomfort. Working on the slow paced running and gradually exposing the hamstring to greater speeds.4
Return-to-Play Phase:
Running Rehabilitation: When returning to play it is important to work on gradually exposing running loads with speed, intensity and change of direction. It is vital to gradually expose the hamstrings to the game demands. As part of the running phase, sport-specific drills to assess and test the body’s readiness to play.6
Returning to training: Once completing rehab running for the hamstring, the next stage is returning to training and the demands required. Once training has been performed adequately the next stage is returning to playing the sport.
Before returning to sport full strength, flexibility, pain free motion and the ability to complete full training is required.
PREVENTION OF RE-INJURY:
Recurrent hamstring injuries are common, with studies reporting rates as high as 12-31% within the first year after an initial strain.5,6 Preventive strategies include:
Hamstring strengthening: Maintaining hamstring strength is a key prevention to injury to ensure the hamstring is strong through their full range of motion. Hip and knee dominant hamstring movements should be completed as the hamstrings cross the knee and hip. Eccentric movements such as the Nordic hamstring curl have been shown to reduce the risk of re-injury.
Dynamic stretching: Ensuring you have a good warm-up routine to enhance muscle flexibility assists the hamstrings in being ready for the activities or sport you are going to perform.
Load management: Load management for running, sport and strengthening is required to allow enough time for the muscles to recovery between sessions. Gradually progressing in training intensity and volume are also important to not complete something too quickly.
CONCLUSION:
Early diagnosis and appropriate treatment are crucial for effective recovery from hamstring strains. Consulting a physiotherapist can provide personalized rehabilitation strategies to facilitate a safe return to daily activities and sports. Hamstring strains, though common, can be effectively managed with prompt and appropriate care. By understanding the underlying anatomy and employing evidence-based rehabilitation, individuals can achieve optimal recovery and reduce the risk of future injuries.
REFERENCES:
Petersen J. & Holmich P. Evidence based prevention of hamstring injuries in sport. British Journal of Sports Medicine. 2005 Jun; 39(6), 319–323. DOI: 10.1136/bjsm.2005.018549
Heiderscheit B. C, Sherry M. A, Silder A, Chumanov E. S, & Thelen D. G. Hamstring Strain Injuries: Recommendations for Diagnosis, Rehabilitation, and Injury Prevention. Journal of Orthopaedic & Sports Physical Therapy. 2010 Feb; 40(2), 67-81. DOI: 10.2519/jospt.2010.3047
Gaku Tokutake, Rieko Kuramochi, Murata Y., Shota Enoki, Koto Y, & Shimizu T. The Risk Factors of Hamstring Strain Injury Induced by High-Speed Running. PubMed. 2018 Nov 20, 17(4), 650–655.
Huygaerts S., Cos F., Cohen D. D, Calleja-González J, Guitart M, Blazevich A. J, & Alcaraz P. E. Mechanisms of Hamstring Strain Injury: Interactions between Fatigue, Muscle Activation and Function. Sports (Basel). 2020 May 18; 8(5), 65. DOI: 10.3390/sports8050065
Wing C. & Bishop C. Hamstring Strain Injuries: Incidence, mechanisms, risk factors, and training recommendations. Strength and Conditioning Journal. 2020 Jun; 42(3), 40-57. DOI: 10.1519/SSC.0000000000000538
Mendiguchia J., Martinez-Ruiz E., Edouard P., Morin J.-B., Martinez-Martinez F., Idoate F., & Mendez-Villanueva A. A Multifactorial, Criteria-based Progressive Algorithm for Hamstring Injury Treatment. Medicine and Science in Sports and Exercise. 2017 Jul; 49(7), 1482-1492. DOI: 10.1249/MSS.0000000000001241
