Figure 3. Mean BESS score (a) and mean RMSacc of sensors mounted on the sacrum (b) and shank (c) in all conditions The error bars indicate standard deviation. a significantly different from DLSfi, b significantly different from DLSfo, c significantly different from SLSfi, d significantly different from SLSfo, e significantly different from TSfi, f significantly different from TSfo. BESS, Balance Error Scoring System; CAI, chronic ankle instability; CON, control; DLSfi, double-leg stance on firm surface; DLSfo, double-leg stance on foam surface; SLSfi, single-leg stance on firm surface; SLSfo, single-leg stance on foam surface; TSfi, tandem stance on firm surface; TSfo, tandem stance on foam surface.