Hamstring injuries have been reported as one of the most common sporting injuries across a variety of sports that involve repetitive kicking and high speed running, such as soccer, track and field, football, and rugby. Re-injury rates are also an issue affecting many athletes long term, with roughly 30% of athletes suffering a re-injury to the hamstring within the first year. As such, risk factors, injury mechanisms and prevention strategies are essential for coaches and athletes participating in these high-risk sports.
The hamstrings are a group of 3 muscles whose main purpose is to bring the hip back and bend the knee. They play a major role in many daily activities involving walking, running, and jumping. The majority of injuries to the hamstrings are grade 1-2 strains that occur during sprinting, especially as the muscles contract eccentrically to decelerate the leg. Injuries that occur during running usually take an average of 16 weeks to return to pre-injury level. Injury can also occur during activities like dancing and kicking where the muscle is overly stretched. Research has shown that an injury due to over stretching of the muscle will take much longer to heal, with an average of 50 wks to return to pre-injury level (Heiderscheit et al., 2010).
Due to the high prevalence of hamstring injuries, combined with a devastatingly long recovery and high probability of re-injury, research has focused greatly on risk factors and rehabilitation strategies to help prevent hamstring injuries altogether.
Unfortunately, the older you get, the higher your chance for hamstring injury. The age when the risk starts to significantly increase is 25 years old, with research suggesting a 30% increase in risk annually thereafter.
Although a lot of prevention programs focus on only stretching the hamstrings, research has shown that tight hamstrings are not a significant risk factor for injury, interestingly, tight hip flexors and/or quads have been associated with increased hamstring injury.
Although research is conflicting, there are some studies showing that an increased BMI (Body Mass Index) is a risk factor for hamstring injury. Furthermore, research consistently shows that race plays a role, with an increased incidence of hamstring injuries in aboriginal, African and Caribbean populations vs. caucasians.
Time of injury
Research suggests that most hamstring injuries occur later in games/practices and are related to fatigue.
Hamstring strength alone is not an important risk factor for injury, but rather the balance between the quads and the hamstrings strength plays an important role in injury prevention. More specifically, athletes with significantly stronger quads vs. hamstrings (as commonly seen with athletes in kicking sports) were at a significantly higher risk of hamstring injury.
Previous injury to the hamstring, groin and/or knee is one of the most commonly reported risk factors for a hamstring injury. Studies show that even a mild hamstring strain will put you at risk for further injury to the hamstring within the following 2 years.
What can you do right now to keep your hamstrings healthy?
Rehab your Injuries
Whether it’s your knee, groin, lower back or actual hamstring, you need to address the injury sooner than later in order to prevent long-term problems and re-injury. The high rate of re-injury can be related to decreased eccentric strength in the hamstring, tightness related to scar tissue and altered biomechanics.
Eccentric Strengthening Programs
Eccentric strengthening programs have been demonstrated in numerous studies to significantly reduce the prevelance of hamstring injuries. Some common eccentric hamstring exercises widely researched are the Nordic Hamstring exercise, the Glider, and the Diver. Click here to learn more about these exercises.
Work on your core
One main problem with most rehab programs is that they only isolate the hamstrings. Research has shown that the hip flexors, core and pelvic musculature play a major role in injury prevention. A recent study compared a core stability program focusing on trunk stabilization and agility vs. a traditional program of hamstring stretching and strengthening following an injury. Results showed that the core stability group returned to sport sooner and had a reoccurrence rate of only 7% during the year, compared to the traditional rehab group, which took longer to return to sport and had a reoccurence rate of 70% during the year (Sherry and Best 2004). Click here to see the core stability program.
Most hamstring injuries occur later in the game when fatigue sets in. Therefore, you must ensure that your conditioning program focuses on interval speed training and endurance training to improve overall conditioning.
As with all injury prevention programs, warming up is key! Studies have shown that the FIFA 11 warm-up program has been successful in the prevention of many different injuries. Click here to learn more about the FIFA 11 program.
Some studies have shown a reduced risk in players who wear thermal shorts, which help keep muscles warm during training.
Take home message:
Many risk factors for hamstring injuries are not preventable, so work on what you can control:
- Core stability, flexibility and strength
If you still have questions about your injury, or want more guidance on injury prevention, book an appointment with one of the Sheddon Therapists.
Heiderscheit et al., (2010). Hamstring strain injuries: Recommendations for Diagnosis, Rehabilitation and Injury Prevention. Journal of Sports Physical Therapy. 67-81.
Liu et al., (2012). Injury rate, mechanism, and risk factors of hamstring strain injuries in sports. A review of the literature. Journal of Sport and Health Science. 92-101.
Prior et al., (2009). An evidence based approach to hamstring strain injury. A systematic review of the literature. Sports Health. 154-164.