Ask the Experts: Can I be too flexible?
Yes, you can be too flexible. This may come as a surprise, since you've probably been told countless times to stretch more.
"There's been a lot of controversy about flexibility in the last decade from a performance and injury standpoint," says Pete Holman, a physical therapist and Director of Rip Training at TRX. Researchers have recently found that having too much flexibility may carry just as much risk of injury as too little flexibility." [1,2]
Holman explains that static stretching if you're not warmed up—either before exercise or when you're trying spontaneously to alleviate a tight spot—causes physical changes in the ligaments that connect your bones together. He says, "This is really taboo because it changes the length of ligaments and affects the stability of your joints. The last thing you want to do is stretch your ligaments and cause lasting changes, because you're setting yourself up for an injury."
You'll also put your performance at risk. "Your muscles will lose their elastic band recoil effect if they're too stretched out," Holman adds. This physical ability is critical for nearly all explosive skills, including sprinting, jumping, throwing a ball and swinging a bat.
A former U.S. Taekwondo National Champion, Holman says he probably overstretched during his career. "I needed to be hyper-mobile in my hips for high kicks," he explains. "However, a football, hockey or lacrosse player will never need that ability."
Athletes in sports like gymnastics, which require extreme levels of flexibility, also experience lasting problems. "We see a lot of people in the physical therapy setting who were formerly hyper-mobile," Holman says. "They complain of low back pain well after their athletic careers are finished, and we find that their lower backs are extremely loose instead of stable. Joints that are supposed to be held in position are lax, because they overstretched."
This doesn't mean you should avoid stretching. You just need to find a balance between mobility and stability. Perform a dynamic warm-up before practice or competition and static stretch major muscle groups for five to 10 minutes during your cool down. And make sure to regularly strength train—performing all exercises through a full range of motion—to develop the muscles that support your joints.
 Jones, B. H., and J. J. Knapik. "Physical Training and Exercise-Related Injuries: Surveillance, Research and Injury Prevention Military Populations." Directorate of Epidemiology and Disease Surveillance, U.S. Army Center for Health Promotion and Preventive Medicine.
 Thacker, S. B., J. Gilchrist, D. F. Stroup, and C. D. Kimsey, JR. "The Impact of Stretching on Sports Injury Risk: A Systematic Review of the Literature." Med. Sci. Sports Exerc., Vol. 36, No. 3, pp. 371–378, 2004.
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