US researchers have found a simple, inexpensive screening tool that can predict athletes at risk of ankle injuries during soccer training and help them avoid it.

In their study, team players who were unable to complete a ‘single-leg balance’ test on one or both legs were two-and-a-half times more likely to sprain their ankles during the subsequent season than those who could complete the test. The relative risk rose to just under nine times more for those who failed the test and then didn’t go on to tape their ankles.

Ankle sprains are a common and potential disabling injury, especially in team sports like American football, soccer and volleyball, the researchers point out. Ankle sprain accounts for 12-20% of all sports injuries and causes 16% of all sports injury time loss.

Athletes scoring badly on stabilometry tests, which measure balance disturbances, have been shown to be at increased risk of ankle injury. But stabilometry equipment is expensive and not readily available for pre-participation examination (PPE). So these researchers set out to test whether the single-leg balance (SLB) test, which uses no equipment at all, would be a useful alternative for predicting ankle sprain.

A cohort of 230 college and high school athletes from American football, men’s and women’s soccer and women’s volleyball were screened at the end of their PPE, using the SLB test.

The test involved the athletes closing their eyes for 10 seconds while standing on one foot without shoes, with the other knee bent and not touching the weight-bearing leg. An athlete scored ‘positive’ if he or she was unable to carry out the test on either or both legs.

The participants were then followed up through the season to record the incidence of ankle sprains.

Over this 14-week period, 28 ankle sprains were reported in the 230 athletes. And the researchers were able to show that athletes with a positive SLB test were significantly more likely to incur this injury, particularly if they did not tape their ankles.

Interestingly, a history of previous ankle injury was not associated with future ankle sprains in this study, although people with previous injuries were more likely to do badly on the SLB test.

The researchers comment: ‘While the SLB test served as a predictor of injury, the exact mechanism responsible for this increased risk of injury remains unknown.’
Further research is needed to determine this mechanism – but meantime the findings support the role of taping in athletes at increased risk.

Br J Sports Med 2006; 40:610-613