Oslo Sports Trauma Research Center

Intoduction

In the October edition of the British Journal of Sports Medicine, professor Roald Bahr and professor Ingar Holme have reviewed the research methodology for studies designed to investigate potential risk factors for sports injury.

In this review, they have used the case of hamstrings strains an injury type which is very common in soccer and other types of football as an example.

They conclude that the major limitation of the existing studies on this injury type is that they are too small to detect small to moderate associations between potential factors and injury risk. The review shows that to detect moderate to strong associations 20-50 injury cases are needed, whereas small to moderate associations would need about 200 injured subjects.

Different methods for studying risk factors are discussed in the new article

Another significant limitation of the studies conducted to date, is that most of them focus on only one risk factor at a time. This approach may lead to improper conclusions. For instance, a study examining the relationship between flexibility and injury risk may conclude that reduced range of motion is a risk factor. However, it may be that reduced range of motion is only seen in previously injured athletes, a result of scar tissue formation and inadequate rehabilitation. A previous injury can also lead to reduced ROM or reduced strength, thereby indirectly affecting injury risk. The take-home message is therefore that studies on the etiology of sports injuries need to account for the multifactorial nature of sports injuries by including as many relevant risk factors as possible, so that their combined and independent effects can be examined properly.