Australian physiotherapists who have conducted trials into the benefits of stretching said they found no evidence that it prevents injury.
"We were able to rule out even a quite small effect of stretching," Rod Pope, an army physiotherapist, told the weekly science magazine.
"This has not been properly researched before. Stretching was assumed to work in preventing injury, but there is no evidence to suggest it did," he added.
Pope and researchers at the University of Sydney and Charles Sturt University in Wagga Wagga studied more than 2,600 army recruits for more than a year. Some of the recruits stretched before exercising and others did not.
The researchers said there was no difference in the injury rates of the two groups.
Pope suggested that stretching after exercising could be helpful or if muscles are particularly tight, which could restrict the normal range of movement.