Stretching has been advocated for years by coaches, trainers and many in health care as a significant way to prevent and decrease sports related injuries. Unfortunately, this belief is more myth than fact. Don’t get me wrong, stretching has its place but it is very much misunderstood.
Flexibility is not what prevents injury. Research shows us that injury rates are higher among athletes with both the most and least flexibility. It is well accepted that most injuries tend to occur as the joint is going through its normal range and contracting eccentrically. An eccentric contraction is when the muscle contracts as it lengthen such as in downhill running. Stretching will not change eccentric loading and it may actually mask muscle pain. There is evidence that aggressive stretching may even weaken the tissue attachment.
Warm up, not stretching, is the key to injury prevention. The research suggests that warm up prepares the muscle for activity by increasing blood flow thereby increasing tissue temperature and metabolism. Conversely, warm up has no effect on range.
Stretching still has merit. Unequivocally, it has been shown to improve flexibility and range of motion. Many sporting activities require extreme range of motion for peak performance such as gymnastics, dancing and martial arts. For those that do not such as running, stretching should probably not be your primary focus.
In physical therapy, stretching is an important adjunct to treatment. Many injured and post operative patients demonstrate muscle spasms, stiffness and scarring which show huge benefits when stretching is used in conjunction with warm up.
Athletes that incorporate warm up, strengthening, balance, agility and stretching have been shown to improve overall conditioning and decrease injury rates. Starting with a light 10 minutes bike ride, brisk walk, jog or swim and then initiating a stretching routine will deliver the best results. Stretching a muscle cold is not recommended and can even cause injury.
When stretching is indicated, there are two proven techniques one may use. Proprioceptive Neuromuscular Facilitation stretching (PNF stretching) involves alternating stretches with muscle contractions. Alternatively, static stretching requires holding a passive stretch for a given period of time to increase tissue length. The PNF method is far superior but is not easy to teach. Static stretching is the gold standard because it is easy and safe.
Static stretching can be enhanced to achieve PNF like results. As previously mentioned, starting with a 10 minute warm up routine is one way. Passive heating or icing, in conjunction with static stretching, can provide a superior stretch to static stretching alone. Although it seems counter intuitive, icing and stretching produces a greater range of motion benefit than the application of heat.
Stretching duration is open to debate. The maximal range of motion benefit is usually achieved by the 4th or 5th repetition of a 30 second hold. Shorter stretches of 15 seconds are believed to achieve the same long term effect as a 30 second stretch but only after several additional weeks of diligent stretching. Hands down, a 30 second stretch achieves increased range faster. It’s important to note that duration can vary depending on the muscle group being stretched, the individual and the presence of any injury. Some muscle groups take 2 to 3 repetitions to achieve full benefit while others 5 or 6.