Figure 2. Balance Error Scoring System (a) double-leg stance on a firm surface (DLSfi); (b) single-leg stance on a firm surface (SLSfi); (c) tandem stance on a firm surface (TSfi); (d) double-leg stance on a foam surface (DLSfo); (e) single-leg stance on a foam surface (SLSfo); (f) tandem stance on a foam surface (TSfo).