This was an amazing article and I want to let everybody know about how I found out this paper and how you can get some great sports medicine/training advice by “reading” more articles yourself (this is an awesome resource)!
First off this article is titled: The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. This article was published in the British Journal of Sports Medicine, 2014; 48:871-877, Lauersen, JB et al. if you would like to read the entire article. Even though this is a short article it is not an easy read, see below.
This paper I thought was fascinating in weird way. Although I read the paper, I did not really ‘read’ the paper. The article talked a lot about statistics, lots of statistics. I cannot actually tell you even if they used the correct type of statistics but the outcomes in which they found were pretty astonishing to say the least.
What these guys looked at where different ways to prevent sports injuries (how to stop an injury before it occurs). They looked at how strength training, stretching, proprioceptive (balance) and multi exposure (combinations of strength training, stretching, proprioceptive training, I think of ‘boot camps’ or other exercise classes) all contributed to a reduction in sports injuries.
Let’s do a quick review on what a systematic review is and what constitutes a meta-analysis (below are my definitions, the way I think of SRs and MAs. If you would like formal definitions, I would Google the terms or look on Wikipedia).
A systematic review is when criteria are made, i.e. how to reduce sports injuries, then the scientific literature is searched. This usually given a few hundred articles. The articles are then pared down to the ones that actually meet the criteria. Also, a systematic review only looks at randomized controlled trials (RCTs). There are many different types of research studies but RCTs are the only ones included when doing a systematic review. This is one of the weaknesses of a systematic review, there may be some great research but if it was not done in a RCT format, it does not get included.
A meta-analysis is a systematic review but all the studies included have their statistics included. So then a statistical analysis of all the studies can be performed. This can be very powerful and give a lot of information. As more and more studies are included in the meta-analysis, there are more subjects in the studies. That gives a lot of power to the study.
For example, say you read that doing ‘x’ helped 80% of people return from an injury sooner. That sounds good and read that the study only had 5 people in it. So 4/5 people got back faster. Which is good but not very powerful. What happens if the study claimed the same thing but had 10 000 people in the study? Wow, doing ‘x’ helped 8000 people in a randomized study get better!! That is pretty amazing stuff. My point is the larger the sample size, the more valid the results. This is why a meta-analysis can pull some amazing numbers, and this one did!
The researchers found 25 studies that included 26 610 participants (that is some huge statistical power) and 3464 injuries. Here is what they found:
Stretching (either before or after): had no beneficial effect
Proprioception: reduced more than multi but less than strength
Multi exposure: had some effect but less than proprioceptive training
They also looked at acute and overuse injuries. Both would be reduced and overuse injuries could be reduced by almost half with strength training!
One criticism of the study what that there was not standard of what was encompassed in a multi exposure session. For example was multi exposure, 90% stretching and 10% strength training in one study and 90% strength training and 10% stretching in another study or did one study include yoga and the others included pilates...
The one thing that came out of the study was that strength training was crucial for the prevention of sports injuries. I could be messing up the statistical analysis but strength training could help prevent sports injuries by 2/3!
There was always a question that I wondered when treating clients, should I get them stretching first or strengthening first. I have chosen over the years to get people strengthening first then stretching. If you get the client's muscles firing and working/strengthening, the muscles can do more without getting injured (or re-injured).
Second part of what I wanted to share with you was how I originally found the article. I started following a gentleman on Twitter called Yann Le Meur, early in 2015. This researcher does these awesome pictures/animations of sports science studies and puts them up on his website/ blogspot. Here is his website site address:
As you can see he has hundreds of these ‘studies’ up on his website. You can search them on the categories on the right hand side (you have to scroll down a bit).
The study animations are all done in English!
This website is a gold mine for people looking to learn about the sport sciences! Well done, Mr. Le Meur, my hat goes off to you, Sir, for making such a brilliant website.