How do ankle braces affect braking performance? An experimental driving simulation study with healthy volunteers

BACKGROUND: Fitness to drive a car has been investigated increasingly over recent years. However, most research has focussed on perioperative driving performance, and few data are available on how orthoses influence the ability to perform an emergency stop. This study investigated the effect of 4 common ankle braces (Kallassy, CaligaLoc, Air-Stirrup, ASO) on reaction time, foot transfer time (together: brake response time) and brake force. The hypothesis was that wearing these braces on the right ankle impairs braking performance, specifically by increasing foot transfer time, but also by altering brake force. METHODS: A car cabin was set up with measurement equipment to register reaction time, foot transfer time, brake response time and brake force under realistic spatial constraints. A crossover repeated measures design was used to test 30 healthy volunteers with and without each of the braces. RESULTS: All 4 braces resulted in statistically significantly increased foot transfer time (p < 0.001), compared with measurements without a brace. Reaction time with a brace was significantly prolonged, with the exception of the Kallasy. Brake force was not statistically significantly impaired. CONCLUSION: This study demonstrates that ankle braces lead to impaired braking performance. Depending on the type of brace, a stopping distance increase of more than 1 m at 100 km/h can be expected.