The World Cup opens in June 2026 here in North America. Already, many high profile players including Lamine Yamal, Alphonso Davies, Mo Salah, Achraf Hakimi, and Reece James have suffered hamstring injuries that put their availability for the World Cup in doubt. Soccer/Futbol often involves sudden sprinting or acceleration which may increase susceptibility to hamstring injury. Hamstring injuries represent the most common non-contact muscle injury.1-2 The hamstring complex includes the semimembranosus, semitendinosus, and biceps femoris short and long heads, and acts in concert to extend the hip and flex the knee.1,3 Research findings reveal an estimated incidence of .87 per 1000 hours of exposure in non-contact sports and up to .96 per 1000 exposure hours in contact sports4 and these rates continue to increase.
Multiple injury mechanisms have been described for hamstring strains including sprinting, overstretching open chain movements with simultaneous hip flexion and knee extension similar to kicking in soccer, and overstretching in a closed chain weight bearing position with the foot fixed in the ground to decelerate possibly during landing or lunging movements.9 The most common mechanism of hamstring injury occurs during the late stages of swing phase during a sprinting gait owing to rapid and excessive eccentric strain of the hamstring. 9,13 Sprinting injuries most commonly involve the biceps femoris portion of the hamstring, while stretching injuries more commonly involve the semimembranosus.1
Hamstring injury severity varies widely and may be graded from 1 through 3 depending on the size of the tear, the symptoms, and loss of strength and/or function.1 Grade 1 injuries involve microscopic tearing with minor swelling and discomfort and little to no loss of strength, while grade 3 injuries involve a complete rupture and total loss of function and may require surgical repair.
Regrettably, there is mixed evidence regarding the ability of imaging to predict injury prognosis and return to sport time following hamstring strain.10-12
Time lost from sport related to hamstring strain can be significant and reinjury rates for hamstring strain are high. Time loss from competition may generally range from 3-28 days or more depending on the severity of the injury.14 Recurrence rate for hamstring strains varies from 13.9% to 63.3% across various studies, and those who have a history of prior hamstring injury have a 3.6 times higher risk of future hamstring injury.14-15
Given the high risk of reinjury and significant time loss from sport following hamstring injury, it is critical to attempt to prevent hamstring injuries and to undergo comprehensive rehabilitation following these injuries.
There are several risk factors shown to contribute to hamstring injury risk. Some risk factors are non-modifiable and some are modifiable. Non-modifiable risk factors may include age, sex, and previous hamstring injury.17 Modifiable factors include hamstring flexibility and muscle length, poor hamstring to quadriceps strength ratio, pelvic control, exercise volume/workload, lumbar pathology, and neural tension and fatigue.16-18,23
Injury prevention and rehabilitation programs should attempt to comprehensively address the modifiable risk factors. Substantial evidence confirms decreased hamstring injury incidence when a strength and conditioning program integrates key injury prevention elements including: strengthening, specifically eccentric training, sprinting, trunk and lumbopelvic control training, and trunk and lower extremity mobility and flexibility training. Exercise selection in a strength and conditioning program designed to limit hamstring injury risk has many considerations. Due to the hamstrings function to extend the hip and flex the knee, it is important to include both hip and knee dominant exercises. Knee dominant exercises work hamstrings with a knee flexion function and hip dominant exercises work hamstrings via a hip extension function.30
Hip extension exercises may more effectively target the proximal and lateral hamstring like biceps femoris.29
This bias toward biceps femoris activation is important due to the high frequency of biceps femoris involvement in most hamstring strain injuries.
Knee dominant exercises commonly target more medial hams and distal hamstrings involved in stretch type injuries.
The Nordic hamstring exercise has been shown in multiple research studies to reduce hamstring incidence by up to 51%.25 Nordics improve biceps femoris architecture and elicit structural changes to increase muscle fascicle length which may correlate to protective effects with hamstring injury.32-33 These changes have also been shown to improve muscle volume and force production.34 There are multiple variations of the Nordic Hamstring exercise, but research currently shows that a dorsiflexed or plantarflexed ankle position doesn’t matter and both are equally effective.35
Eccentric lengthened state hamstring exercises like RDL’s (shown in the hip dominant videos above) were also shown to be effective in inducing general hamstring hypertrophy and also to elicit specific changes at biceps femoris long head.36 The single leg Romanian deadlift exercise has also been shown to target the hamstrings more effectively than other traditional hamstring exercises and offers the added benefit from training and developing the hamstrings eccentrically which is a common mechanism of injury.26 Further evidence exists that eccentric training may modify hamstring muscle architecture and structure to improve injury durability. Further evidence supports training the hamstrings at longer lengths to mimic the injury mechanism stress.20 Following a hamstring injury, evidence exists that some evidence of atrophy and scarring at the hamstrings remain 6 months after injury despite the return of function and strength. These changes may influence future reinjury risk and limit capacity or resilience at the hamstrings.28
Both the Nordic hamstring and Romanian deadlift exercises should be staples of an injury prevention and rehabilitation for hamstrings, based on current evidence and the ability to eccentrically train the hamstrings and improve hamstring to quad ratio.27
The hamstrings attachment on the pelvis at the ischium makes it imperative to add trunk and pelvic strengthening exercises to limit anterior pelvic tilt and excessive strain on the hamstrings. Modeling by Chumanov et al. showed that the hamstrings and lumbo-pelvic complex were coupled during high-speed sprinting.22 An anterior pelvic tilt has been shown to increase hamstring strain.23-24 There is further evidence that anterior pelvic tilt is modifiable and trainable and that exercises stressing trunk control may reduce hamstring injury rate.23-24,38 There is also evidence that trunk and pelvic muscle activity is altered in subjects who went on to sustain a hamstring injury.39-40 Exercises to address pelvic rotation and lateral flexion are critical, as well as glute musculature to limit excessive hamstring strain.31,41
ANTERIOR TRUNK STABILIZATION
LATERAL TRUNK STABILIZATION
ROTATIONAL TRUNK STABILIZATION
Exercises emphasizing hip extension are critical due to the synergistic role of gluteus maximus and adductor longus and magnus with the hamstrings, especially during horizontal force production such as sprinting.19-20 Research shows that these muscles may reduce strain on the hamstring musculature. Exercises targeting adductors and gluteus maximus are an essential component of both rehabilitation and injury prevention programs.
Isometrics may produce soft tissue changes and condition the hamstrings to improve fatigue resistance.30 They should be implemented at lower intensity (30-50% MVIC) and longer holds (20-30 secs).30
Although the role of hamstring flexibility including active knee extension deficit remains controversial, hamstring mobility can be addressed through static and/or dynamic stretching. Limited evidence exists in using dynamic hamstring mobility exercises to address flexibility for rehabilitation, injury risk and prevention.29 Additionally, there is evidence that the hip flexors on the opposite leg may impact pelvic mechanics and influence hamstring strain as well. Including hip flexor mobility and flexibility is another important consideration in rehab and injury prevention via coupled actions and forces on the pelvis.22
DYNAMIC WARMUP HAMSTRING MOBILITY
Due to the frequency of hamstring injury during sprinting, injury prevention and rehabilitation programs should also include sprint training as well as hamstring strengthening exercises with sprint-specificity carryover.42 Studies show that hamstring muscle activation during sprinting far exceeds hamstring activation during traditional strength training exercises.43 Some research shows that the Nordic hamstring and the upright hip extension exercises are related to horizontal force production needed for sprinting warranting inclusion in a comprehensive program.44 Including those exercises in a rehab and/or injury prevention program may be beneficial due to the high propulsive forces on the hamstring with early sprint accelerations and required hip extension.19 There is also some evidence that improving sprint technique and specific postural training may limit hamstring injury risk.45
Lastly,improving the fatigue resistance at the hamstrings is another critical training element to limiting injury risk and fully and effectively rehabilitating hamstring injuries for a return to sport.46 Hamstring endurance and fatigue resistance training may limit a decline in hamstring strength following intense training load and competitions.46-47
Hamstring injury has been extensively studied, specifically in soccer athletes due to the high injury rate , high rate of reinjury or recurrence, and time loss from sport. There is emerging evidence that steps can be taken to limit hamstring strain risk and improve recovery following hamstring injury to limit reinjury and keep athletes safe and healthy. Understanding the risk factors for hamstring injury, mechanical role of the hamstrings, regional interdependence and influence of the kinetic chain on hamstrings, and effective exercises to target hamstrings and functional training specificity is critical to designing an effective rehabilitation and injury prevention program.
