Stretch before you exercise -- it's an oft-repeated maxim, but the benefits of stretching have not been conclusively proven. The goal of stretching is to prevent musculoskeletal injuries by making soft tissue structures, including ligaments, tendons and muscles, more pliable and less likely to overstretch or tear. Although stretching has become a mandatory part of most sports routines, it might actually increase rather than decrease the risk of injury, in some cases. Stretching might help with some sports and not others. Talk with your trainer or medical provider about the benefits and risks of stretching for you.
Research is Contradictory
Research on the benefits of stretching in preventing injuries has not firmly established a benefit. A Canadian review of available studies published in the October 1999 "Clinical Journal of Sports Medicine" stated that while some studies found a benefit of stretching combined with other warm-up techniques, others reported no benefit and several found that stretching increased rather than decreased the risk of injury. But a University of Alabama study reported in the 2007 issue of "Sports Medicine" claimed that stretching combined with warm-up exercises did help prevent injury. This report states that stretching within 15 minutes before starting an activity had benefit.
Stretching Might Hurt Rather Than Help
The 1999 Canadian study noted five reasons why stretching might increase the risk rather than help prevent sports injuries. The first was that, in animal studies, heat-induced muscle compliance increased the risk of soft-tissue rupture. Researchers also stated that stretching appears to mask muscle pain, which would prevent you from recognizing an injury immediately and stopping an activity. Lastly, researchers explained that stretching can cause damage at the cytoskeleton, or cellular level. Bouncing when you stretch rather than simply holding your stretch for 30 seconds can cause tissue injury Harvard Health warns.
Stretching Improves Flexibility
On the plus side, Harvard Health explains that stretching can improve muscle flexibility, which could help improve your range of motion if you have tightness in structures such as the Achilles tendon. Always warm-up for five to 10 minutes with low-intensity exercise such as light walking or biking before stretching. Don't stretch before a high-intensity workout, such as sprinting, because stretching can decrease rather than increase your performance. Stretch at least two to three times a week to maintain the flexibility benefits of stretching.
Stretching Increases Blood Flow
Stretching increases blood flow to your muscles. If you have tissue damage, increased blood flow can increase oxygenation to the damaged tissues and decrease your recovery time. Increased blood flow can also carry away waste products that occur as a byproduct of exercise. Don't stretch to the point of pain and, if you have a current injury, clear any type of stretching with your medical team.