By Jared Campbell.
Have felt your pain in the back of your thigh?
Was it a cramp, a hamstring tear, neuropathic related, myofascial related or tendinopathy related?
A topic I want to dive into is hamstring strains. My own story with hamstrings has catalysed a passion for it. Long story short, I have had my fair share of hamstring tears, strains and tendinopathies. Years and years of participating in high level cricket and hockey, has proven to be strenuous on my hamstrings.
ANATOMY
The hamstrings are comprised of three muscles that cross over two joints, namely the hip and knee joint. The muscles are biceps femoris, semimembranosus and semitendinosus. Given the orientation of the hamstrings and how they cross over two joints, bar the short head of biceps femoris, the hamstrings act on the hip as hip extensors and act on the knee as knee flexors, which is their primary role.
FUNCTION
In sprinting, our hamstrings produce excessive force, especially during the terminal swing phase of running, as the leg swings through, extends and is about to make contact with the floor. It is at this point that our hamstrings are most vulnerable to injury. Especially the long head of biceps femoris, where 80% of hamstring injuries occur (Koulouris et al., 2003)
The hamstrings also help us maintain upright posture during running and work in conjunction with the glutes to extend the leg backwards. This is known as the type I or sprinting mechanism of injury. The acute symptoms of this injury are more severe, depending on the grade, but the recovery period is shorter.
Hamstring strains can also occur in positions of excessive hip flexion and knee extension, this is known as the stretching type or type II mechanism of injury. This is commonly seen in ballet dancers or goalkeepers who have to perform the splits to save a goal. The acute symptoms of this injury are less severe, but the rehab period is longer. The location of this injury, is higher and closer to the sitting bone, at the proximal free tendon of semimembranosus.
RATIONALE
History repeats itself if we do nothing about it. This is where we as physiotherapists have a key role in the rehabilitation and the education of the hamstring injury pandemic. The following statements is what current research is indicating as risk factors.
Increasing age and a previous hamstring injury are the two main risk factors for a hamstring injury according to a recent meta-analysis (Greene et al, 2020). There is also strong evidence to suggest decreased hamstring eccentric strength is a modifiable risk factor, from the same study. Decreased eccentric strength refers to the ability of your hamstring to control your lower leg as mentioned above in the terminal swing phase of running.
Up to 43% of athletes injure their hamstrings again in the same season (Hagglund et al, 2008), which doubles the time absent from sport. (Brooks et al, 2006). We cannot predict how long it will take to return an individual to full function, but we do know that the rehabilitation period will be longer if they have sustained multiple hamstring injuries on the same leg.
PREVENTION
The main aim of rehabilitation is prevention. In this manner, an individual can return to their previous function or level, but most importantly, perform over a longer period of time without injury. Eccentric conditioning significantly reduces the likelihood of another hamstring injury by 65-70% when done compliantly (Goode et al, 2015). Eccentric conditioning includes exercises such as Nordics and glute hamstring raises, which have been shown to be efficient in literature (Bourne et al, 2017). The main physiological defence mechanism we can give ourselves, is more sarcomeres in series. Sarcomeres are the structure within our muscle fibres which contracts. The hamstring needs to lengthen and contract as your swings through when you run. We can give more defence from injury through eccentric training.
CONCLUSION
Hamstring injuries can be dealt with if the necessary preventative measures are taken. If not, it will constantly reoccur. The good news is that I will show you how we treat, rehabilitate and return individuals to full function via my series on the Performance Clinic Facebook page and YouTube. Or Book in to see me 0191 4350560.