Products which are advertised to improve your sports/exercise performance litter the internet and magazines. I've written about a number in this blog and they include things like supplements, drinks, footwear, gadgets and exercise equipment.
While doing a bit of reading for another post (which is taking me longer to write than I'd like!) I came across an interesting article in the BMJ Open about such products which I think is worth writing a few paragraphs about.
The article, titled "The Evidence Underpinning Sports Performance Products: A Systematic Assessment", is a critical review of the evidence underpinning sports/fitness products that make claims about improved performance. Thankfully it strongly supports my assertion that most of this stuff is ill researched and over marketed.
The researchers examined 100 general magazines and the top 10 sports and fitness magazines in the UK and USA in 2012 with the selection having a circulation of 30 million in the UK alone. Each page of each magazine was scrutinised and all adverts were identified and assessed for relevance to sport and fitness and to see if they contained any claims of performance enhancement (improvements in strength, speed and endurance) or enhanced recovery from sports or exercise.
The adverts that fitted into the above criteria included those for:
- sports drinks,
- footwear and
After selection, the websites for each product were examined and all references retrieved. The studies for these references were then critically examined by the reviewers to identify the quality of the evidence and risk of bias. This was done using the Centre for Evidence Based Medicines levels of evidence scale. Put simply, level 1 is the highest evidence criteria and level 5 is the lowest. If anyone wants more detail feel free to click on the link above.
In the end 92 magazines were examined which contained a total of 1807 adverts. Of these 615 advertised sports products of which 235 fitted into the criteria for analysis.
Of the products' websites that were analysed, 1035 web pages were viewed. From these, 431 performance enhancing claims were made for 104 different products with a total of 146 references to studies for these claims. Unfortunately you might say, a third of these references came from one site and more than half of the sites that made claims did not provide any references what so ever!
So now the boring bit is out of the way what did they find out? Well:
- Firstly no systematic reviews were found in the references at all. (Systematic views are essentially a type of literature review that collects and critically analyses multiple research studies or papers. These are really useful when presenting evidence for something as multiple studies are almost always better than one for establishing the quality of evidence.)
- 0% of the studies examined provided level 1 evidence (remember this is the highest form of evidence).
- 43% provided evidence that was categorised as level 3 (essentially not that great)
- 42% provide level 2 evidence (reasonable you might say)
- 12% of the studies outcomes were categorised as level 5 (the worse and least reliable).
As a result the researchers concluded that 84% of the studies were judged to be at high risk of bias meaning that in the future, conclusions are likely to change if and when higher quality research is carried out.
The bottom line here is that it is very difficult for the general public to be confident about the claims made for sports and fitness products. How can the public be expected to make an informed decision to buy a product when the information presented is more often than not of poor quality and high risk of bias.
Manufacturers know however that the public is unlikely to fact check claims and that getting high profile endorsements for their products is far more important than quality research into the claims they make. I wouldn't expect anyone to look into every claim that is made for every product but you can protect yourself from being hoodwinked by taking a default skeptical position. Remember 'extraordinary claims require extraordinary evidence' and in the absence of even mediocre evidence I thinks it's fair to say you should approach any claim about sports and fitness products with caution and take everything you hear or read with a particularly large pinch of salt.
The Evidence Underpinning Sports Performance Products: A Systematic Review. BMJ Open 2012
“Striking lack of evidence” to back up claims for popular sports brands. The BMJ July 2012.