Ian Shrier, MD, PhD, associate professor of sports medicine at McGill University in Montreal, says that the concept of stretching "immediately before exercise is something that has been accepted on theory, but when we examine it clinically, we can see that there is no science behind the principle."
He tells WebMD that people who advocate stretching -- which is just about everyone in the sports medicine community -- do so because they are following the Zen statement, "That which is flexible will not break." That statement, he says, "works for trees and other objects that are taking perpendicular force. But, muscles are stretched end-to-end and when stretched to the maximum may tear."
Shrier discussed his views on stretching here at a recent meeting of the American College of Sports Medicine. Last fall, he first questioned the value of stretching in an article in the Clinical Journal of Sports Medicine. "Everyone criticized me, but recently a study from Sweden validated my claims," he says.
He says that although he doesn't recommend stretching immediately before exercise, stretching does have a place in conditioning. "I think, for example, that it's a good idea to stretch in the morning when you get up and then go about your normal activities. I also think it's a good idea to stretch before going to bed at night," he says.
Moreover, "patients who have stiffness, for example a frozen shoulder, have to stretch to increase range of motion," he says. One of the greatest benefits associated with stretching is increased range of motion. "In this regard, it is true that in some specific sports stretching is necessary. A gymnast needs to stretch out in the splits, for example. Another example is a hurdler who needs to stretch out the muscles to clear the hurdles."
Shrier says that there are also some animal data suggesting that stretching may eventually increase muscle strength. In a strengthening program, "stretching might be prescribed on a daily basis, and after several months, it may increase muscle strength," he says.
One of the little known benefits of stretching comes with "stretch tolerance, in which the stretching acts like an analgesic," says Shrier. Many sports medicine experts attending his lecture protested this notion, but during a heated discussion following the lecture, most agreed that stretching does increase tolerance to pain. "Initially a stretch is painful, but when repeated," he says, "one is not aware of the pain. That's what I call analgesia."
Shrier says that some experts think stretching may enhance performance in some sports, but he remains skeptical. "It appears that sprinters who compete immediately after stretching (within 15 minutes, because in 30 minutes this effect is gone) may actually run faster because the muscle is more elastic and so it doesn't have to work as hard," he says. "Again, however, this is theory, and we need to see science."