Are warm-ups a waste of time?

The elaborate ritual of stretching before and after exercising may have little - or no - effect on muscle soreness, say Australian researchers.

While many fitness experts recommend stretching to prevent injuries, the study - published in the Cochrane Library - suggests that stretching won't keep muscles from getting sore after exercise.

The team identified ten pieces of research involving between ten and 30 volunteers who were either given stretches to do before and after exercise, or told to do none.

Using a 100-point scale to assess stiffness, they concluded that the effects of stretching were extremely small, with most estimates showing that stretching reduced soreness by less than 1 point on the 100-point scale.

"The data were remarkably consistent," says lead researcher Robert Herbert from the School of Physiotherapy at the University of Sydney, Australia, "The available evidence suggests that stretching before or after exercise does not prevent muscle soreness in young healthy adults."

The researchers said that the practice of stretching before or after exercise may have arisen because of the mistaken belief that muscle soreness was due to muscle spasm. But they said that this theory had since been discredited.

Yet they say there is some evidence that once muscle soreness has developed, stretching may provide some relief. The study's authors also say that they did not study the effects of stretching on injury prevention, performance, or well-being, and that further trials would be useful.

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