To have real world significance the results must be statistical significant.
Even if the standard deviation is not high, the lack of data points and lack of similar findings from other studies, makes it relevant to concider if their is a chance the results are not valid. Measurement of hamstrings of flexibility needs to be blinded because subjectiv interprations of pain (strecth tolerance) increases the risk of higher ranges of motion. The best argument is that the acceptet P value is acceptede high because if the results are not valid the intervention is not harmful, just wasting peoples time. What i am hearing Carl argumenting for is that foam rolling is overrated. The above studie is not a bad argument for that.
How is hamstrings flexibility relevant in a real world “elite sport” context? I would love to see these well designed publications providing a clear correlation between hamstring flexibility (measurede as ROM completede before pain onset) and performance, kinematics variables or injury risk. Their is som very low evidence that hamstring strecthing might decrease muscle strains. Foam rolling and strecthing is not the same intervention. Its important to keep focus on which variable we are measuring an effect of.
Does foam rolling decrease injury risk?
Trying looking at muscle extensibility (Magnusson 2010)