Ankle sprains occur when a ligament in the joint is overstretched or torn, often from a sudden twist or awkward landing of the foot. They are among the most common injuries in soccer and can lead to pain and stability problems lasting months or even years for some.

That has triggered a slew of studies into the reasons athletes suffer sprains, but few have focused on soccer players, according to George Vagenas, of the University of Athens, and colleagues.

The researchers did preseason tests of ankle strength and stability in 100 players from four professional soccer teams in Greece. Then they followed the players over the next 10 months to see who would get hurt on the field.

Seventeen players suffered one or more non-contact sprains during the season. Those with considerable strength differences between their left and right ankles were nine times as likely to suffer sprains as those whose ankles were about the same strength. (Specifically, it was the strength of the muscle contractions while muscle is lengthening, as when you stand on your toes and then slowly lower yourself.)

When a player cuts or lands from a jump, Vagenas told Reuters Health by email, it's important to have symmetrical activation of the two sets of ankle muscles to help the joints absorb the impact and prevent damage.

He suggested that "all soccer players, professionals or not, must be evaluated during the preseasonal period by sports specialists for verification of potential functional asymmetry of the ankle joint."

But that might not be realistic, said Timothy A. McGuine, a sports medicine specialist at the University of Wisconsin-Madison.

"Most lay people won't have the time and money to do this kind of screening," he told Reuters Health.

But there is still an important message from the new study, even for amateur athletes, according to Erik Wikstrom, an expert in ankle sprains at The University of North Carolina at Charlotte.

"This study does suggest that if soccer players want to lower their risk of suffering ankle sprains, then they should strengthen their ankle musculature evenly, so that they have a good balance between both legs," Wikstrom told Reuters Health by email.

"This take-home message can apply to just about all athletes and non-athletes," he added. "Proper balance between the lower extremities is very important."

Earlier studies have shown that both lace-up ankle braces and balance training on a "wobble board" can help stave off injuries to the joint.

"I tell people to go ahead and balance on one leg, then the other for two to three minutes," said McGuine, who led those studies, adding that two to three times a week is a good start.

The Greek researchers also found that heavy players were more prone to sprains, which makes sense given the extra force their ankles have to absorb when they land or cut.

Apart from keeping a healthy weight, McGuine told Reuters Health that it's important to learn how to land properly, too.

"Don't land stiff legged," he said. "We want a soft foot strike."

SOURCE: bit.ly/MoUQb5 The American Journal of Sports Medicine, online June 4, 2012.

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