Table 2.
Correlation matrix
| Overground Walking | Treadmill Walking | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Correlation coefficients: | Correlation coefficients: | ||||||||||||||||||
| SD ML | SD V | SD AP | λs* ML | λs* V | λs* AP | λL* ML | λL* V | λL* AP | SD ML | SD V | SD AP | λs* ML | λs* V | λs* AP | λL* ML | λL* V | λL* AP | ||
| SD ML | 1.00 | SD ML | 1.00 | ||||||||||||||||
| SD V | 0.95 | 1.00 | SD V | 0.92 | 1.00 | ||||||||||||||
| SD AP | 0.14 | 0.24 | 1.00 | SD AP | 0.59 | 0.62 | 1.00 | ||||||||||||
| λs* ML | 0.05 | -0.04 | -0.02 | 1.00 | λs* ML | 0.26 | 0.20 | -0.26 | 1.00 | ||||||||||
| λs* V | -0.20 | -0.17 | -0.04 | 0.47 | 1.00 | λs* V | -0.17 | -0.08 | -0.50 | 0.74 | 1.00 | ||||||||
| λs* AP | -0.27 | -0.24 | -0.37 | 0.57 | 0.45 | 1.00 | λs* AP | -0.01 | 0.08 | -0.32 | 0.77 | 0.75 | 1.00 | ||||||
| λL* ML | 0.16 | 0.17 | 0.07 | -0.13 | 0.06 | -0.27 | 1.00 | λL* ML | -0.51 | -0.50 | -0.56 | 0.34 | 0.41 | 0.30 | 1.00 | ||||
| λL* V | -0.31 | -0.37 | 0.10 | -0.23 | -0.24 | -0.28 | 0.41 | 1.00 | λL* V | -0.76 | -0.81 | -0.47 | -0.36 | -0.14 | -0.30 | 0.53 | 1.00 | ||
| λL* AP | -0.47 | -0.52 | 0.17 | -0.13 | -0.01 | -0.36 | 0.55 | 0.75 | 1.00 | λL* AP | -0.77 | -0.82 | -0.57 | -0.37 | -0.18 | -0.21 | 0.45 | 0.86 | 1.00 |
| α (DFA) | -0.45 | -0.35 | -0.39 | 0.09 | 0.10 | 0.51 | -0.09 | 0.08 | -0.09 | α (DFA) | -0.56 | -0.56 | -0.36 | 0.12 | 0.25 | 0.10 | 0.28 | 0.37 | 0.42 |
Pearson's r correlation coefficients between the variables. SD = Mean Standard Deviation (MeanSD). λS* = maximal Lyapunov exponent, short term dynamic stability. λL* = maximal Lyapunov exponent, long term dynamic stability. α = scaling exponent (Detrended Fluctuation Analysis), fractal dynamics. ML, V and AP stand for respectively Medio-Lateral, Vertical and Antero-posterior. Significant correlation are bold printed (p < 0.05).