Hamstring injuries are the most common muscle injury in running based power sports. They are one of the most common injuries in football. While they hardly result in prolonged absence from playing such as an ACL tear, they have a high recurrence rate and can occur in the most well-conditioned athlete. In this article I will briefly discuss what the research suggests to be the best ways to diagnose, treat and prevent hamstring injuries.
Anatomy of the Hamstring
The hamstring is made up of three muscles: the semi-membrabosis (SM), semi-tendinosis (ST) and the biceps femoris (BF), all of which arise from the ischial tuberosity. Of educational curiosity, the superficial elements of the BF is continuous with the sacrotuberous ligament and distally inserts to the lateral part of the fibula. Therefore making it a four joint muscle (i.e including the proximal tibiofibular joint and the sacroiliac joint), whereas the SM and ST are both two joint muscles.
It remains unclear if this anatomical factor has any relevance in determining the risk of hamstring injuries. However, there have been kinematic studies that demonstrate that the BF undergoes a greater lengthening during running in comparison to the ST and SM and has been considered a potential risk. Yet, to date, the relative impact of this anatomical factor continues to be decided.
Causes for Hamstring Injuries
The cause of any given injury, especially the hamstring is multi-factorial in origin and to say that a hamstring injury is due to a single causative factor is unlikely to explain the whole story. Causes can be classified as either intrinsic or extrinsic as seen below.
Intrinsic Age Quadriceps and hamstring flexibility Isokinetic strength Fatigue Previous injuries and surgeries Anatomical factors and biomechanics | Extrinsic Training load Recovery Sports participation |
Prevention
Nordic Hamstring Exercise
Recent studies have suggested that prevention in incidence of hamstring injuries, could be possible by using eccentric exercises. A large randomised controlled trial that included nearly 1000 elite and sub-elite players showed a 10 week pre-season programme including the Nordic hamstring exercise. This exercise focuses on increasing the eccentric strength of the hamstring and was also shown to decrease the incidence of new injuries, as well as reducing the rate of recurrent injuries.
A worthy study to note, which was published in 2010 shows that adding chiropractic care to standard medical and physical therapy approaches significantly decreased the number of back pain, hamstring, lower limb injuries and missed games among Australian professional football players.
It was an 8-month study and was comprised of an ongoing, multi-regional treatment approach integrating both soft tissue techniques and joint based manipulation and mobilization. There was a strong emphasis on high velocity, low amplitude (HVLA) manipulation techniques, with both manual and mechanically assisted techniques being performed.
The HVLA manipulative procedures are thought to return the physiologic and accessory motion to restricted structures, correcting deficits in range of motion and creating instant strength changes in lower-limb musculature following spinal, and lower-limb joint manipulative techniques. This may have contributed to improved hamstring and lower-limb muscle function and injury prevention in this study.
It supports the hypothesis that hamstring and lower limb muscle strain involves a local and distant model. This is why the treatment was applied to non-local hamstring structures, in particular the knee, hip, pelvis and spine and considerably decreased the number of back pain, hamstring and lower limb injuries.
Diagnosis
Diagnosis should begin with a clear history (previous hamstring injuries, low back and hip symptoms, mechanism of injury, surgeries, training load, recovery status, etc). This should be followed by a careful examination including hamstring ROM and strength in both straight leg and flexed hip position. Palpation is an extremely helpful tool. Comparison to the contra-lateral leg should be made. Assessing other joints such as the lumbar spine, hip, knee and proximal tibiofibular joint should be made to check for limitations of excessive ROM.
A report published in 2012 looked at the use of the MR imaging as a prognostic tool for lay-off after hamstring injuries in professional footballers and the association between the MR imaging findings and injury circumstances. It was found that ’70% per cent of hamstring injuries seen in professional football are of radiological grade 0 or 1, meaning no signs of fibre disruption on MR imaging, but still cause the majority of absence days’.
Despite the above study, imaging plays an extremely important role in defining the exact nature of the injury in elite and sub-elite athletes. Both MR imaging and ultrasound have shown to be sensitive for hamstring injuries, which is enhanced when taken 48 hours after the injury. Imaging straight after the injury runs the risk of evaluating a developing injury.
Management
Unfortunately, when hamstring injuries occur they can be a bit tricky and frustrating to fully rehabilitate. Studies have reported re-injury rates are as high as 25% in football players. However, as with all acute muscle injuries, the initial management of the hamstring is critical and should consist of rest, ice, compression, protection from aggravating activities. The use of ice is to reduce bleeding and inflammation. It is recommended to apply the ice for 15-20 minutes, repeated up to two hours for the first 48-72 hours and then four-hourly for a for two-three days.
Early mobilization in a pain free manner should progress successively. As pain allows, active and passive gains in ROM should be initiated through isometric, concentric and eccentric developments. Functional stretching and strengthening is of importance to prevent the recurrence of hamstring injuries, as well as proprioceptive training. Core stability and progressive functional loading should be incorporated and begin with careful supervision from a trained therapist.
A gradual return to the individual training and then selective components of team training is one of the most critical components of the whole process. A sports specific running program can be included and should be progressed through phases, including gradual increase in distance, intensity, speed, duration and frequency.
Non-steroidal Anti-inflammatory drugs (NSAIDs) are not recommended in the acute phase of the injury. There have been studies that have shown NSAIDs will impede muscle and collagen regeneration and fibrosis, which increase the chances of re-injury. For this reason, it is recommended to avoid using NSAIDs.
Please call your Chiropractor at AHS on 9948 2826 or visit our clinic at 9/470 Sydney Rd in Balgowlah servicing the surrounding suburbs of Allambie, Balgowlah Heights, Seaforth, Fairlight and Manly on the Northern Beaches.
References
- Ekstrand J, Healy JC, Walden M, Lee JC. Hamstring muscle injuries in professional football: the correlation of MRI findings with return to play.
J Sports Med 2012;46:112-117 - Hoskins W, Pollard H: The management of hamstring injury–Part 1: Issues in diagnosis. Man Ther 2005, 10:96-107.
- Hoskins W, Pollard H: The effect of a sports chiropractic manual therapy intervention on the prevention of back pain, hamstring and lower limb injuries in semi-elite Australian Rules footballers: A randomized controlled trial. BMC Musculoskelet Disord 2010, 11:64.
- Petersen J, Thorberg K, Nielsen M, Budtz-Jorgensen E, Holmich P. Preventive effect of eccentric training on acute hamstring injuries in men’s soccer: a cluster-randomized controlled trial. Am J Sports Med 2011; 39:2296-2303.