Over time, muscles tend to lose their flexibility which can reduce musculoskeletal function and limit joint range of motion. According to the American College of Sports Medicine, flexibility starts to decline in the third decade of life. Muscle flexibility can also be lost as a result of acute trauma like an accident or surgery or even from years of poor posture. Limited range of motion can be a minor inconvenience - like when you can't quite reach the itch in the middle of your back - or can cause chronic pain and dysfunction. Stretching is one of the best ways to promote or regain flexibility and range of motion but if performed incorrectly, muscles can be further damaged.
Built-in Stretch Receptors
There are many sensors built into the muscle itself to protect it from stretching too far. For example, if you walk across an uneven surface and your ankle rolls the wrong way, the sensory organs within the muscles and tendons determine that the muscles are stretching too far and too fast and immediately cause the muscles to contract in an effort to prevent any sprains or strains. But if the stretch is too forceful or occurs too quickly, damage may not always be avoidable.
Don't Bounce
Stretching activities that are rhythmic and bouncy are called ballistic stretching. An example would be bending forward while bouncing up and down in an effort to reach the toes. The movements are often quick and forceful and work against the muscle's internal stretch reflex. As the body's momentum forces the stretch, the muscles try to contract as the muscle is still lengthening. This can cause microscopic muscle tears or even a strain of the muscle or tendon.
Don't Stretch Cold
Cold muscles are less flexible and more likely to tear. For this reason, it is best to stretch after a pre-exercise warm-up. Five to 10 minutes of light aerobic activity will sufficiently raise the body temperature and increase blood flow to the working muscles. According to the American Council on Exercise, as body temperature and muscle circulation rises, so does muscle elasticity. For this reason, stretching at the end of an exercise session is recommended.
Avoid Pre-Activity Stretching
Many exercisers believe that stretching prior to exercise or physical activity will actually prevent injury. According to research presented by Len Kravitz, PhD, with the IDEA Health & Fitness Association, much of the latest research is not only refuting this but pre-exercise stretching may actually contribute to injury. It is believed that static stretching may compromise joint stability which in turn can lead to injury of ligaments, tendons or muscles. Kravitz further comments that participating in a regular stretching program can positively benefit sports participants as long as stretching is not done prior to activity.
Regular Stretching is Most Effective
There are a number of stretching techniques, but for most populations, the ACSM recommends static stretching. This form of stretching is performed in a long, controlled motion. Physiologically, it takes from 7 to 10 seconds before the muscle actually accepts the stretch and begins to relax. Therefore, holding a stretch for 15 to 30 seconds is optimal for most people. The same stretch can be repeated up to three more times for maximum benefits.
References
- "ACSM's Guidelines for Exercise Testing and Prescription, 7th Edition"; ACSM; 2006
- "American Council on Exercise"; Warm Up to Work Out
- "IDEA"; Stretching-A Research Retrospective
