Is it to improve athletic performance, reduce the risk of injury, or both? If you gave any of these answers, few would challenge your answer – until recently. Now social media outlets are challenging our traditional views by claiming that stretching can hurt athletic performance and is worthless for preventing injuries. What’s going on?
Let’s start by distinguishing between stretching and warming up. A warm-up is designed to increase muscle temperature, circulation, respiration, and provide skill rehearsal to help prepare you physically and mentally for the more intense activities to come. When you should stretch, and how much you should stretch, is a bit more complicated.
How much you should stretch, if at all, depends on what you plan on doing. In sports such as gymnastics and figure skating, which require large ranges of movement, a more extensive stretching program may be necessary than, perhaps, recreational jogging. In contrast, athletes who are involved in sports that have a high-speed component, such as sprinting, should consider stretching for an entirely different reason – to reduce muscle tension.
Michael Ripley, D.C. a sports medicine doctor who has worked with over three dozen track and field athletes who have competed in the Olympics, says that sprinting creates a high level of muscle tension not just during, but after training. “This tension will cause muscles to shorten, and without post-stretching, I've found that over time this causes shortening of the athlete's range of motion. In my opinion, it's most important to stretch immediately after the workout because you help keep the body symmetrical. In contrast, if you waited several hours, you have to stretch for a considerably longer amount of time to achieve the same effects.”
One of the most referenced studies on the effects of stretching to prevent injuries was published in the British Journal of Sports Medicine in 2001. The study involved 6972 women and 3421 men who played basketball. The researchers noted that the average amount of time these athletes missed due to an ankle injury was 2.2 weeks and that those who previously injured an ankle were five times more likely to injure it again. Where does stretching fit in?
There are two major calf muscles, the gastrocnemius and the smaller soleus. Proper function of these muscles can only contribute to a basketball player’s jumping ability, but and also help ensure optimal running and jumping biomechanics. As evidence, in this study the researchers concluded that the athletes who did not stretch before games “...were 2.6 times more likely to injure an ankle than players who did not.” It’s also believed that tight calf muscles are associated with flat feet and shin splints.
Although these results are encouraging, there is conflicting research suggesting that stretching may have little or no effect on reducing injuries in other body parts. One example is the hamstrings, as the preponderance of research indicates that there is no link between knee flexor range of motion and hamstring injuries. In one study that observed elite soccer players from Norway and Iceland over four seasons, the researchers found no difference between the number of hamstring injuries between athletes who performed a hamstring stretching intervention program and those who did not. That said, it could be argued that the researchers were stretching the wrong muscles.
The psoas is a hip flexor muscle that runs from the front of the upper thigh to the lower back. Excessive psoas tightness can tilt the pelvis anteriorly (down and forward). This postural change can affect running mechanics and possibly increase the risk of a hamstring injury (as the change in pelvic tilt increases the stress on the hamstrings). With hamstring injuries, increased eccentric strength has been proven to be one of the best ways to reduce hamstring injuries, but stretching the muscles that flex the hip may be valuable.
In recent years, there is concern about the possible adverse effects of stretching on power, jumping ability, and sprinting speed. This belief can be traced to a review of 106 articles that found that static stretches performed for a minute or longer can decrease athletic performance in speed-dependent skills. Further, decreases in strength in the range of 7-20 percent have been observed immediately after stretching, and there is research on cyclists that stretching can adversely affect muscular endurance. The key here is when stretching is performed.
If stretching is performed immediately before a sports skill, then yes, athletic performance can be decreased for up to two hours. However, the effect is gradual. Stretching one hour before an athletic practice or weight training workout will have less of an impact as stretching immediately before practice. The solutions are to stretch long before a practice or competition, or stretch after – which is better, as the muscles will be warm and more receptive to stretching. Another option is dynamic stretching.
Dynamic stretching has you move your limbs rapidly throughout a large range of motion under control and does not adversely affect athletic performance. Also, consider that there is a weak correlation between dynamic flexibility and static flexibility, such that it’s possible that someone who has difficulty touching the floor from a standing position might be able to kick you in the head if they move their limbs rapidly. Thus, dynamic stretching could be considered to be more sport specific for many athletes. A practical resource on this subject is the book Stretching Scientifically: A Guide to Flexibility Training by Thomas Kurtz (4th edition, 2003).
One other type of stretching is a partner-assisted method called PNF, which is an acronym for proprioceptive neuromuscular facilitation. PNF involves having an individual being stretched perform an isometric contraction in the stretched position. Another type of partner-assisted stretching method is called Fascial Stretch Therapy™, which was created by Ann and Chris Frederick. This type of stretching is performed on a treatment tape with straps to stabilize the limbs not being worked so that the focus can be on the specific muscles you want stretched. Both PNF and Fascial Stretch Therapy should be performed by trained practitioners as they require considerable skill to master.
Stretching has been around a long time and has survived its critics. However, to get the most out of it, especially if your focus is athletic fitness, it’s important to understand what types of stretching there are, how much stretching you need, and when to stretch.