The Truth about stretching
Phil Campbell reviews the research work conducted on static and dynamic stretching
A three-year-old study about stretching is being cited in many articles today, and the conclusions reached by some writers may be harmful to the muscle, ligaments and joints of your athletes.
Is stretching before exercise harmful?
Stretching before athletic training and general fitness improvement exercise is being made out to be a time waster, not needed, and even harmful. This is not true. In fact, there is a recent study that evaluates all the research on stretching, and the study concludes:
"Due to the paucity (small number), heterogeneity (dissimilar study subjects) and poor quality of the available studies no definitive conclusions can be drawn as to the value of stretching for reducing the risk of exercise-related injury" (Weldon 2003).
Essentially, the researchers are saying that there are not enough quality studies to draw conclusions about this issue.
Study in question
The study that is generating all the hoopla was performed by the Kapooka Health Centre, New South Wales, Australia on 1,538 army recruits. It is a credible study designed to show the occurrence of lower limb injury on a group of young army recruits. Despite what you may have heard about stretching before training, this is what the researchers actually reported:
A typical muscle stretching protocol performed during pre-exercise warm-ups does not produce clinically meaningful reductions in risk of exercise-related injury in army recruits. Fitness may be an important, modifiable risk factor (Pope 2000).
The statement, "Fitness may be an important, modifiable risk factor" is very important. It simply means that age, weight, and conditioning of the study subjects may be an important factor in preventing or facilitating the injuries experienced in this study.
Three years after the Kapooka study, another study involving military recruits was conducted and the researchers in this study show that pre-training static stretching can prevent injury involving muscle but not joint or bone injury. The researchers report, "Static stretching decreased the incidence of muscle related injuries but did not prevent bone or joint injuries" (Amako 2003).
Based on the way some have written about this study, it is okay to run a 100-meter sprint full speed without stretching beforehand. Now, this may be possible for a small number of lean, young army recruits. However, does anyone believe that a powerful, muscled athlete or a middle-aged and older adult can go out and run a sprint, cold with no warm-up and without increased risk of injury? Do not think so.
Use Common Sense...and the full body of research
Think about it; if an out of shape, untrained young army recruit performs a high-intensity exercise, he may get injured, pre-stretched or not. And this is why researchers evaluating all the research on stretching conclude, "No definitive conclusions can be drawn..." In short, there needs to be a body of research based on age, weight, conditioning, and the study needs to be performed functionally for the specific sport and type of exercise before life-changing conclusions are drawn.
The truth about stretching
New research shows that stretching can aid in the prevention of injury or stress fractures that plague distance runners. Researchers conclude, "Prevention of stress fractures is most effectively accomplished by increasing the level of exercise slowly, adequately warming up and stretching before exercise, and using cushioned insoles and appropriate footwear" (Sanderlin 2003). Stretching offers many benefits. Researchers show that prolonged stretching (in the form of yoga) with moderate aerobic exercise and diet control will reduce cholesterol and significantly reverse hardening of the arteries (20% regression) in adults with the proven coronary atherosclerotic disease. After one year in a yoga program, participants lost weight, reduced cholesterol, and improved their exercise capacity (Manchanda 2000). Stretching offers many benefits, but there is an issue about the type of stretching and the timing of stretching before athletic competitions.
Use dynamic stretching before games and key practice sessions
There are two main types of stretching, static (holding a stretching exercise in one position without movement) and dynamic stretching, which means moving while stretching (arm swings, knee rotations, neck circles). Researchers show that athletes should not perform prolonged static stretching before the big game or a key practice session because this slows muscle activation for around an hour afterwards (Fowles 2000). Using dynamic stretching is a wise pre-competition strategy. Static stretching builds flexibility and should be performed regularly, just not immediately before a big game or a key practice session. Warming up prior to a high-intensity, ballistic, athletic event is an absolute rule, never to be broken, and stretching can be combined (multitasked) as part of the warm-up. The goal of the warm-up is to get the blood flowing and raise body temperature (one degree) prior to athletic competitions and high-intensity training. It is desirable to have the athlete's muscle, ligaments, and joints experience the functional range of motion required of the sport during the warm-up.
Do static stretching with 30-second stretch-holds away from practice
Gains in flexibility are dependent on the "duration" of stretch-hold position, and researchers show the best "stretch-hold position" (for time spent) to increase flexibility is 30 seconds (Bandy 1994). "Best" means optimal results for time spent. You can get positive results with 2-minute stretch-holds, but 30 seconds yield equal results.
This type of stretching is positive for athletes and adults of all ages. Researchers show in one study that long-held stretching positions are of great benefit for adults over age 65, "Longer hold times during stretching of the hamstring muscles resulted in a greater rate of gains in a range of motion (ROM) and a more sustained increase in ROM in elderly subjects." (Feland 2001).
Adults aged 21 to 45 with tight hamstrings also get the best results from static stretching with 30-second stretch and hold positions. Researchers report that static stretching is two times more effective than a dynamic range of motion (DROM) for this group of non-competitive athletes. Researchers report, "The results of this study suggest that, although both static stretch and DROM (dynamic stretching) will increase hamstring flexibility, a 30-second static stretch was more effective than the newer technique, DROM, for enhancing flexibility" (Bandy 2001).
Keep in mind there are important lessons in these studies, but the studies apply to a specific age group (over 65, and ages 21 to 45) and a specific physical condition (tight hamstrings). If we apply the results of a study with these variables to young athletes, we may be wrong. While it is reasonable to conclude (as I have for training purposes) that static stretching away from practice is an effective strategy for athletes with tight hamstrings, this study does not specifically prove that point. It is clearly a mistake to take the findings of one study and create an absolute fact. Look at the whole body of research about a topic before making a life-changing training decision.
The take home about stretching
Use dynamic stretching and static stretching at the correct times in the training plan. Dynamic stretching (arm swings, hip rotations and knee rotations) will aid in the pre-competition, pre-practice warm-up process by increasing flexion in the joints and increasing body temperature. This method is preferred before athletic competition. Static stretching can be used as part of a warm-up for training. However, static stretching will slightly slow down athletes for an hour afterwards so examine training goals. The best way to improve overall flexibility is static stretching with 30-second stretch and holds performed away from events requiring peak performance.
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About the Author
Phil Campbell is a personal trainer and a master athlete holding several USA Track and Field Master titles. He has a black belt in Isshinryu Karate and has competed and won titles in martial arts and weightlifting competitions. His Sprint 8 cardio program is featured in award-winning Vision Fitness treadmills and exercise bikes.
The following Sports Coach pages provide additional information on this topic: