Stretching before or after exercise has little or no effect on subsequent muscle soreness, research shows.
Many people warm up or down
A Cochrane Collaboration analysis of 10 trials found stretching reduced soreness by less than one point on a 100-point scale.
However, the researchers said it might be more help for people with reduced flexibility.
And a UK expert stressed the main reason to stretch was to prevent injury, rather than soreness.
The researchers looked at trials involving 10 to 30 people in which the volunteers were asked to stretch from between 40 seconds and 10 minutes.
The effect on subsequent soreness was tiny, and similar if the stretching was performed before or after activity.
Lead researcher Robert Herbert, from the University of Sydney, said: "The data were remarkably consistent.
"The available evidence suggests that stretching before or after exercise does not prevent muscle soreness in young healthy adults."
John Brewer, director of the Lucozade Sport Science Academy, said people should not be put off stretching because of the findings.
He said: "The main reason to stretch before exercise is not to reduce soreness, but to reduce the risk of injury.
"It lengthens the muscles, improves their elasticity and makes them better prepared to cope with the duress of exercise."
Mr Brewer said the benefits of stretching after exercise were less clear.
However, he said a warm down could potentially help the muscles recover by increasing blood flow to the tissue, and helping to flush away waste products generated during exercise.