There are two main types of sports injuries: traumatic (sprains, muscle pulls, ACL tears and fractures) and overuse (strains, tendinitis, shin splints). Some traumatic injuries are the result of a lack of flexibility, which is why it is important for athletes of any age to warm-up properly before sports.
A proper warm-up loosens muscles and tendons to increase range of motion of joints, and, of course, to literally, warm up the body by increasing body heat and blood flow. This is because warm muscles and enlarged (e.g. dilated) blood vessels use oxygen from the blood and burn fuel stored in the muscles more efficiently. For aerobic sports such as soccer, basketball, tennis, lacrosse, hockey) a proper warm-up has two components: aerobic exercise and dynamic stretching.
Light aerobic exercise
A proper warm-up begins with 5 to 10 minutes of warm-up jogging at a very easy pace (40% of maximum heart rate), increasing to 60%, followed by a 5-minute recovery period. This portion of the warm-up should neither be performed too early (warming up and then sitting for 30 minutes may leave the player stiffer than they were before) or intensely (if the aerobic exercise is too vigorous, the player will end up tired).
The second part of a warm-up regimen, to be performed immediately after the aerobic warm-up and as soon as possible before a practice or match, involves dynamic stretching (stretching muscles while moving).
For sports that involve rapid movement in different directions, such as soccer, basketball, volleyball and tennis, players need to perform stretching exercises that involve many different parts of the body. Here are some suggested dynamic stretches :
Straight-leg march (hamstrings and gluteus muscles)
- kick one leg straight out in front, with the toes flexed and pointed straight up;
- reach the opposite arm to the upturned toes;
- drop the leg and repeat with the opposite leg and arm
- repeat sequence at least 6 or 7 times
Scorpion (lower back, hip flexors and gluteus muscles)
- Lie on stomach with arms outstretched and feet flexed so only toes are touching ground
- Kick right foot toward left arm, then kick left foot toward right arm
- Begin slowly and repeat up to 12 times
Handwalks (shoulders, core muscles, hamstrings)
- Stand straight with legs together
- Bend over until both hands are flat on ground
- "Walk" with hands forward until back is almost extended
- Keeping legs straight, inch feet towards hands
- Walk with hands forward again
- Repeat 5 or 6 times.
Dynamic stretching works
Studies show that the new way of stretching (dynamic stretching) increases power, flexibility and range of motion, and may reduce injuries. In one study of female collegiate soccer players, non-contact ACL injuries were reduced by nearly half among players who followed a warm-up program that included both dynamic stretching exercises and static stretching. In another, researchers at Bloomsburg University of Pennsylvania found that golfers were nine times less likely to be injured if they warmed up.
Static stretching decreases performance, doesn't prevent overuse injuries
Research has shown that the kind of stretching routine most of us have been doing since we were in grade school (holding a stretch for 20 or 30 seconds, supposedly to prepare muscles for exercise, or static stretching) not only fails to do what it is supposed to do but may actually weaken muscles and hurt athletic performance.
Studies have found that static stretching weakened muscle strength by as much as 30 percent and that stretching the leg muscles in one leg reduced strength in the other leg for up to 30 minutes after stretching. While a player may think that static stretching increases flexibility, what is actually happening is that the stretching has simply increased the athlete's mental tolerance for the discomfort of the stretch, while the muscle itself is actually weaker! Studies have made it increasingly clear that static stretching alone before exercising doesn't reduce the traumatic injury risk.
In a new study1 reported on the website of USA Track and Field, the sport's national governing body, 1,400 runners age 13 to 60, were randomly assigned to two groups, one that did not stretch before their runs but otherwise maintained their normal workout routines, the other which performed a series of simple, traditional static stretches, such as leaning over and touching their toes and holding for 20 seconds.
After three months, the injury rate for the static stretching group was virtually identical to that for the group that did not stretch. Static stretching "neither prevented nor induced injury when compared with not stretching before running," the study's authors concluded. Static stretching seemed to have little benefit in terms of injury prevention, particularly against the overuse injuries common in running, and many sports.
"In all our involvement with elite athletes now, we don't do this kind of static stretching anymore," said Dr. Ross Tucker, a physiologist in South Africa. Instead, the ideal pre-workout routine, science suggests, consists of a very easy-warm up, followed by a gradual increase in intensity and then dynamic stretching.
Gradual change recommended
Experts recommend, however, that the change in routine to aerobic warm-up and dynamic stretching be done gradually, because sudden changes are probably not a good idea.
Static stretching (standing in one spot, such as bending over to touch your toes or hamstring stretch) is still recommended immediately after practices, games and matches.
Revised September 7, 2010
1. Pereless D, Roth A, Thompson Darby JS. "A Large, Randomized, Prospective Study of the Impact of a Pre-Run Stretch on the Risk of Injury in Teenage and Older Runners" http://www.usatf.org/stretchStudy/index.asp (accessed September 7, 2010)