Published November 11, 2011
Going through a set of warm-up exercises before practices and games cut the rate of knee and ankle injuries in girls playing soccer and basketball in a new study.
Fewer of the high school students suffered noncontact injuries, including anterior cruciate ligament (ACL) sprains, when their coaches were trained to lead the warm-up sessions.
Researchers said that training coaches in these exercises may be a low-cost way to prevent injuries that sometimes require expensive surgeries -- and may turn girls off from physical activity. Exercise in teen girls has been linked to better grades, less obesity and lower pregnancy rates.
"We see that girls that are active in sports are less likely to get involved in some of these other high-risk behaviors, so keeping them active and making sure an injury doesn't take them out is important," said Dr. Cynthia LaBella, from the Northwestern Feinberg School of Medicine in Chicago, who worked on the study.
Warm-ups, she added, are "worth the time and the money invested for the long-term health of the girls."
Tim Hewett, head of sports medicine research at The Ohio State University and Cincinnati Children's Hospital, said that during puberty, both girls and boys shoot up in height, but girls' muscles don't develop as much as boys' do.
Because of that imbalance, studies have shown they get between two and 10 times more injuries like ACL sprains than boys, he added.
"The good news in all this is, these imbalances that we observe can be corrected with neuromuscular training," Hewett, who was not involved in the new study, told Reuters Health.
LaBella's study involved mostly low-income girls playing on high school soccer and basketball teams in Chicago public schools. Ninety coaches were randomly assigned to be taught a warm-up program involving strengthening, balance and agility exercises to lead before every game and practice, or to stick with their usual warm-up routine.
The warm-up also involved exercises focusing on how to jump and land safely. The regimen was designed to take about 20 minutes, and coaches were given a DVD and laminated card to help them keep track of the exercises.
Over the course of the season, they recorded whenever one of their athletes missed a practice or game due to a leg, ankle or foot injury.
About 1,500 girls were included in the study -- half on teams that did the warm-up program, and half on teams that didn't. In total, there were 96 injuries during the 2006-2007 season in the "control" group that did no extra stretching and strengthening, compared to 50 injuries in girls who did the warm-ups.
Specifically, there was a 35 percent reduction in leg overuse injuries with the warm-up program and a 44 percent lower rate of acute non-contact injuries.
The researchers calculated that three or four coaches would need to be trained in the exercises to prevent one gradual-onset injury and between 11 and 16 coaches to prevent an ACL sprain or any type of injury that required surgery.
Even the cost of training 16 coaches, at about $1,300, would be significantly less than the $17,000 or more needed for ACL surgery, they wrote in Archives of Pediatrics & Adolescent Medicine this week.
Some coaches might not want to use the warm-up program because it takes time out of already limited practices, LaBella and her colleagues said. Along those lines, coaches that were instructed to do warm-ups as usual, without learning the exercises, generally didn't do them at all or had athletes do warm-ups themselves, they found.
"Coaches oftentimes are hesitant to take practice time away from skill development," LaBella told Reuters Health. "They may only get the gym for an hour."
But, she continued, "We really feel like it should be a routine part of sports training for teenage girls. It's worth the investment."
Hewett said that the warm-up exercises, when done correctly, can improve jumping height and power -- not just prevent injuries. That's one way to sell them to coaches, he said.
"You can make a huge difference in the athleticism of these girls," Hewett said. "There's many ways we can show these kids that they're faster, quicker, more balanced athletes."