Examining the research evidence on running injury prevention can be a somewhat fruitless task. We've commented previously on the 'skimpy research' in this field. So it's encouraging when approaches that make a great deal of sense start to show promising results in the literature. One such approach is strength training and a recent review shows it may be very effective in reducing injury rates…
Lauersen et al. (2013) performed a systematic review with meta-analysis of randomised controlled trials that examined interventions for preventing sports injury. Reviews of this type are usually considered as a high level of evidence to guide our practice, although they are not without their limitations. The study included 25 trials with a total of 26,610 participants and 3464 injuries. Impressive numbers! Their aim was to determine the effectiveness of stretching, strength training, proprioceptive exercise and combined approaches in preventing sports injuries. They concluded;
“Despite a few outlying studies, consistently favourable estimates were obtained for all injury prevention measures except stretching. Strength training reduced sports injuries to less than 1/3 and overuse injuries could be almost halved“
Encouraging results and it seems that of the approaches used strength training was most effective. This makes a great deal of sense when you consider the reported effects of strength training. It is thought to improve the muscle and tendon's ability to manage load, to improve running economy and to be an effective treatment option in a number of conditions. Strength training can be incorporated into a simple model to reduce risk of running injury;
But before we get carried away there is a major limitation in generalising the results of this study to all athletes… Out of the 25 studies included 0 were specific to runners.
The trials included athletes, footballers, army recruits and general members of the public but none were focused on reducing injury risk specifically in runners. This doesn't mean the results our meaningless to the running community, the fact that the review showed benefits across several populations is encouraging, but we need to interpret the results cautiously.
Any study needs to be examined in the wider context of research in this area. There is a growing body of evidence showing multiple benefits from strength training as discussed in a recent systematic review – Kristensen and Franklyn-Miller (2012). They had the following key findings;
- Resistance* training is effective in treating most common musculoskeletal injuries (including tendinopathy, back pain and osteoarthritis of the knee).
- It's effective across age and gender
- A high intensity approach using more than 70% of 1 Rep Max (see diagram below) is more effective than a low intensity approach but requires a gradual introduction to heavier loads.
* Note: the terms 'strength training' or 'resistance training' refer to the same approach – exercising with progressively heavier loads to improve muscle strength, power, hypertrophy or endurance.
Several studies have also reported improved running economy following strength training as discussed in more detail here.
So the evidence is growing to support making a strength and conditioning programme a regular part of training but what of stretching? Stretching has been a stalwart of running for years but recently has recieved a bit of a bashing from the research. Studies have suggested static stretching in particular may be detrimental to performance. Findings from Lauersen et al. (2013), although not specific to running, appear to add further weight to the argument that stretching may not be helpful;
“Our data do not support the use of stretching for injury prevention purposes, neither before or after exercise”
They do point out however that this is based on just 3 studies, 2 on army recruits and one internet based study.
Closing thoughts: a growing body of evidence supports the use of strength training for athletes but research on runners remains somewhat lacking. The exact details of what to strengthen and how to do it are likely to be highly individual depending on your goals, strengths and weaknesses. Common muscle groups to target include quads, hamstrings, calf muscles and glutes. Strengthening these muscles may prove effective but I suspect building a programme based on the assessment of a physiotherapist or health professional will achieve better results. As ever on RunningPhysio if in doubt get checked out!