Ben Klaphake

Stretching before exercise does not prevent injuries. A 2014 meta-analysis of 26,610 participants in the British Journal of Sports Medicine found that stretching had no effect on injury rates at all. Strength training cut injuries by a third. The study was led by Jeppe Bo Lauersen at the University of Copenhagen. His team pooled every randomised trial that tested whether exercise-based programmes could prevent sports injuries, and compared the results by type: stretching, strength training, balance work, and combinations. Stretching reduced nothing. Strength training reduced injuries by 33 percent and cut overuse injuries, the ones that build up slowly over weeks, by nearly half. The reason stretching fails is that it addresses the wrong problem. A muscle tear happens when a muscle is asked to produce more force than it can handle. Making a muscle longer does not make it stronger. Strength training does, and it also thickens tendons and stiffens the connective tissue around joints, all of which protect against the sudden loads that cause tears and sprains. The finding goes against what every gym teacher, track coach, and physical therapist has said for fifty years. But the data is not close. Across every trial, every sport, and every injury type, stretching before exercise had zero detectable effect on whether the person got hurt. This does not mean flexibility has no value. It means the five-minute hamstring stretch before a run is doing nothing for injury prevention, and replacing it with five minutes of bodyweight squats and lunges would be measurably better. The body does not need to be looser before it works. It needs to be ready to handle load, and that is a strength problem, not a flexibility problem. pubmed.ncbi.nlm.nih.gov/2410…