Table 5. Idiosyncratic determinants of sway amplitude.
| R2 | MARS Model | ||
|---|---|---|---|
| FA_EO | ML | 0.13 | BF1 = max(0, AGE-40), y = 6.09 + 0.09*BF1 |
| FA_EC | ML | 0.22 | BF1 = max(0, AGE-32), BF2 = max(0, 1-SEX), BF3 = BF2 * max(0, 27-AGE) y = 6.49 + 0.04*BF1–1.03*BF2 + 0.38*BF3 |
| FT_EO | ML | 0.25 | BF1 = max(0, 42-AGE), BF2 = max(0, 1-SEX), BF3 = max(0, 58-AGE) y = 9.34 + 0.21*BF1–0.96*BF2–0.16*BF3 |
| FT EC | ML | 0.22 | BF1 = max(0, AGE-28), BF2 = max(0, 28-AGE), BF3 = max(0, SEX), BF4 = max(0, HEI-1.77) * max(0, AGE -43) y = 7.34 + 0.06*BF1 + 0.29*BF2 + 1.57*BF3 + 3.57*BF4 |
| FF EO | ML | 0.10 | BF1 = max(0, SEX), BF2 = max(0, HEI -1.67) * max(0, AGE -60) y = 7.09 + 1.51*BF1 + 8.98*BF2 |
| FF_EC | ML | 0.26 | BF1 = max(0, AGE-28), BF2 = max(0, 28-SEX), BF3 = max(0, SEX) y = 8.23 + 0.13*BF1 + 0.74*BF2 + 1.62*BF3 |
| OA EO | AP | 0.21 | BF1 = max(0, AGE-40) * max(0, 3.5-EXE) y = 16.11 + 0.08*BF1 |
| OA_EO | ML | 0.36 | BF1 = max(0, AGE-27)*max(0, MAS-67), BF2 = max(0, AGE -27)*max(0, EXE-3.5), BF3 = max(0, MAS-82), BF4 = BF3 * max(0, 35 -AGE), BF5 = max(0, 82-MAS) * max(0, AGE-27), BF6 = max(0, 82-MAS) * max(0, 27-AGE) y = 10.05 + 0.04*BF1–0.07*BF2–1.03*BF3 + 0.15*BF4 + 0.01*BF5 + 0.06*BF6 |
| OA_EC | AP | 0.33 | BF1 = max(0, AGE-32), BF2 = BF1 * max(0, EXE-3), BF3 = max(0, 1.75-HEI), BF4 = max(0, 65-MAS) * max(0, 32-AGE) y = 37.37 + 1.47*BF1–0.25*BF2–110.20*BF3 + 0.46*BF4 |
| OA_EC | ML | 0.27 | BF1 = max(0, 33-AGE), BF2 = max(0, 46-AGE) y = 108.31 + 10.73*BF1–5.49*BF2 |
| BA_EO | AP | 0.22 | BF1 = max(0, AGE-29), BF2 = max(0, 29-AGE) y = 36.05 + 0.83*BF1 + 2.38*BF2 |
| BA_EO | ML | 0.14 | BF1 = max(0, 29-AGE), BF2 = max(0, AGE-29) * max(0, HEI-1.79) y = 139.65 + 7.67*BF1 + 70.05*BF2 |
Results of the MARS models. Sway amplitude (RMS) for each standing task is the dependent variable (y). Predictors are age (AGE), sex (SEX), height, (HEI), mass (MAS), and exercise (EXE). BF: basis function. AP: anteroposterior. ML: mediolateral. EC: eyes closed. EO: eyes open. For other abbreviations, see Table 2.