Pre-exercise stretching was once part of the normal warm-up ritual of almost all strength, power, and endurance athletes. Most fitness experts said that stretching increased muscle and joint range of motion, which made movements easier and reduced the risk of injury. It turns out that pre-exercise stretching is a bad idea that decreases performance and increases the risk of injury. Pre-exercise stretching reduces muscle strength and power and interferes with the brain’s ability to control the muscles.
Greek researchers found that muscle power decreases the longer you stretch the muscle. They measured the effects of stretches lasting from 10 seconds to 60 seconds on isometric strength and power. Stretching for 30 seconds decreased isometric strength by nearly 9 percent, while stretching 60 seconds decreased power by 16 percent. Stretching 30 seconds or longer has similar effects in decreasing muscle power. They recommended that athletes avoid static stretching of muscles for 30 seconds or more before activities requiring maximum strength and power.