A warm-up is thought to allow tissues literally to become heated, to reach a temperature at which they are, presumably, more flexible and malleable and ready for the demands of further exercise. But it hasn’t been proved that warm muscles perform better than colder ones or that they are less prone to injury, Dr. [Brian] MacIntosh said.
According to the largest review and analysis to date of the research on warm-ups, which was published last year in The Journal of Strength and Conditioning Research, a warm-up was “shown to improve performance” to a limited extent in most of the sports studied, which included running, swimming, cycling, golfing, basketball, softball and bowling. But as the review’s lead author, Andrea Fradkin, an associate professor at Bloomsburg University in Pennsylvania, told me, most of the studies were small-scale and short-term, and their methods were inconsistent. ...
None of the studies persuasively showed that any one approach to warming up was best, or even that a warm-up necessarily would make you significantly better at your sport or prevent injury.
The science about how to warm up “is not well advanced,” Dr. Fradkin said. “We haven’t answered the big questions yet,” she said, about whether to warm up or why to warm up, “let alone the smaller, specific ones” about how.
--Gretchen Reynolds, NYT, on how to save another 10 minutes in your workout