Today we’re talking hamstrings, and in particular hamstring strains.
The hamstrings are a collection of 4 muscles that live at the back of the thigh; the 2 biceps femoris muscles on the outside (lateral) part of the thigh, and the semimembranosus & semitendinosus muscles on the inside (medial) part of the thigh.
They perform many roles, but are most important to act as a ‘brake’ to control of the swing of the leg with running & kicking, as well as providing power to propel us forward when running.
Not all hamstring strains are the same…
Recognising this is important, as what causes them and how we treat them can be very different!
For hamstring strains, there’s two main types:
‘Low’ hamstring strains, which typically happen when we’re running fast, and generally involve the lower part of the biceps femoris muscle (specifically, the long head) on the outside of the thigh; and
‘High’ hamstring strains, which are caused by over-stretching the muscle – such as if we do a high kick in football, or trip and stumble when running. We call them ‘high’ hamstring strains as they are generally up closer toward the buttock, and typically more involve the inside part of the hamstring (semimembranosus) – and also generally involve a longer period of recovery.
Here, we’re mainly going to be talking about ‘low’ or ‘sprint-mechanism’ hamstring strains – the ones that happen when we run fast!
So why do they happen?
Well, think of the muscles as being a bit dumb – they can do one thing, but ask them to do two things at once, and they can really struggle.
Muscles can contract and work, and they can also stretch or lengthen. Doing either of these things is pretty easy for the muscle – but when we run, we ask the hamstrings to both work and stretch at the same time, which is particularly hard work for them.
Ask them to do two things at once at high speed….and you can see why the muscle can struggle to cope!
Of course, there are other risk factors involved too…
Above all else, the biggest risk factor for straining your hammy is having done it before. The high recurrence rate is one of the big problems associated with hamstring strains, with those with a past history of injury being up to 6 times more likely to do another one. Increasing age is also a risk, but it’s not just an ‘over-30s’ thing – the age at which you become ‘old’ from a hamstring perspective, and your risk of injury increases, is at about 23 years!
However, we can’t change how old we are, and nor can we change our past history of injury – so what we focus on is modifying the risk factors we CAN change.
Interestingly, the research shows no strong link between hamstring flexibility and hamstring strains – it seems that having good hamstring flexibility doesn’t make you any less likely to get injured.
However, having greater hamstring strength, and in particular having hamstring strength at length, does – and there’s a number of really good studies that show that athletes with stronger hamstrings get injured less.
Both treating an existing hamstring injury, and preventing one from happening in the first place, revolve around that same principle – getting stronger in positions where our muscle ins on stretch.
So what exercises are best for hamstrings?
Particularly if you’re recovering from a hamstring injury, this is something that’s best guided by your physio – particularly as what’s appropriate for you to be doing can vary according to the extent of your injury, and how far along in your recovery you are…what you need to do exercise-wise after a couple of weeks will likely look very different to what you need to do after the first few days!
1. Brukner, (2015). Hamstring injuries: prevention and treatment – an update. British Journal of Sports Medicine, 49(19), 1241-1244.
2. JOSPT (2022). Hamstring strain injury in athletes: a summary of clinical practice guideline recommendations: using the evidence to guide physical therapist practice. Journal of Orthopaedic & Sports Physical Therapy, 52(3), 127-128.
3. Green et al. (2020). Recalibrating the risk of hamstring strain injury: a 2020 systematic review and meta-analysis of risk factors for index and recurrent hamstring strain injury in sport. British Journal of Sports Medicine, 54(18), 1081-1088.
4. Askling, et al. (2012). High-speed running type or stretching-type of hamstring injuries makes a difference to treatment and prognosis. British Journal of Sports Medicine, 46(2), 86-87.
5. Prior, et al. (2009). An evidence-based approach to hamstring strain injury: a systematic review of the literature. Sports Health, 1(2), 154-164.
Sports Physio North Adelaide