Hamstring injuries are one of the most common injuries that athletes and recreational sports players face. And once you’ve had one, you are much more like to suffer from another!
Therefore, prevention is better than cure - but how do you go about preventing a hamstring injury?!
Understanding how the injury happens
If we want to prevent it, we first have to understand how it is likely to happen! It is thought that most hamstring injuries take place during the late swing phase of the running gait cycle when the hip is flexed and the knee extended. In this position there are high levels of muscle excitation and muscle strain as the hamstrings contract eccentrically to decelerate the previously accelerated limb then moves to concentric contraction to produce hip flexion – the muscles at this point have reached peak length, producing the largest force and doing the most negative work.
Risk factors for hamstring injuries can include:
- Previous injury
- Increasing age
- Ethnicity
- Strength differences
- Decreased flexibility
- Fatigue
Changing the risk factors that we can
It stands to reason that most prevention activities would concentrate on those risk factors that we are able to change – namely flexibility and strength deficits.
Perhaps one of the exercises for hamstring injury prevention that has gained momentum in the last few years is the Nordic Hamstring Extension (NHE). The NHE has been shown to reduce the incidence of hamstring injuries by 50%.
However, there can be some issues with the NHE – a lot of people are unable to perform them correctly (at least to begin with, if they are done enough, then most people are able) and it does not strengthen the hamstring in the lengthened position – which, as previously mentioned, is where most hamstring injuries are thought to take place. In fact, similar strengthening programs that do not include the NHE also show similar prevention results (50% vs 48%).
The main glaring problem in reaching conclusions on the effectiveness of certain strengthening programs is that volume of exercise is not fully described. Some researchers will list reps/sets, some duration whilst some will simply miss it out altogether!
If you imagine this is like having a list of ingredients to make a cake but not the measurements of each ingredient – not very helpful, right?!
What else can we do?
Passive stretching of the hamstrings has also been shown to reduce the occurrence of hamstring injuries, with decreased hamstring flexibility being linked with hamstring injuries – Witvrouw et al. (2003) found a 6° smaller range of motion in football players that had been previously injured. Increasing hamstring flexibility seems to be useful in reducing hamstring injuries that occur due to inability to cope with being in a maximally stretched position.
Another intervention that appears to be helpful is balance training in order to improve inter-muscular coordination. Adding just 5 minutes of balance training to a warm up has been shown to reduce the occurrence of hamstring injuries. A home based balance exercise program helped to reduce the incidence of injury in female football players. It consisted of 5 exercises performed everyday for 1 month and then 3 times a week thereafter (Soderman et al., 2000).
The main takeaway from current research regarding prevention of hamstring injuries is the importance of strengthening the hamstring through an eccentric contraction (NHE, RDL etc), increasing flexibility and balance training.
I hope you found this information helpful – next time we will cover what to do if you have already suffered a hamstring injury!