TABLE 1.
Summary of linear mixed model analyses for various models.
| Model | β0 (SE) | β1 (SE) | F | P | Adj. R2 |
| Grip force | |||||
| Ln(meanGF) = β0 + β1(D) + bi + ε | 6.527 (0.044) | 0.244 (0.061) | 16.4 | 0.0001*** | 0.465 |
| Ln(maxGF) = β0 + β1(D) + bi + ε | 6.512 (0.042) | 0.318 (0.061) | 26.54 | < 0.0001*** | 0.375 |
| Ln(sdGF) = β0 + β1(D) + bi + ε | −6.724 (1.182) | 10.401 (1.896) | 30.963 | < 0.0001*** | 0.209 |
| HR and HRV | |||||
| Ln(LF/HF) = β0 + β1(D) + bi + ε | 1.333 (0.235) | 0.21 (0.37) | 3.33308 | 0.0693⋅ | 0.19 |
| Ln(LF) = β0 + β1(D) + bi + ε | 5.852 (0.257) | −0.15 (0.354) | 1.2628 | 0.2624 | 0.453 |
| Ln(HR) = β0 + β1(D) + bi + ε | 4.438 (0.038) | 0.097 (0.025) | 41.89 | < 0.0001*** | 0.882 |
| Ln(HF) = β0 + β1(D) + bi + ε | 4.546 (0.264) | −0.262 (0.331)a | 0.6404 | 0.4244 | 0.51 |
mean GF, mean grip force; maxGF, maximum grip force; sdGF, standard deviation of the grip force; LF, HF, and LF/HF, heart rate variability measures; HR, heart rate, D, maximal deceleration (−g) during the braking event; bi, random effect parameter for driver i; ε, error term. aHRV HF’s negative value represents the inhibitory pattern of the parasympathetic system during stressful situations. It is assumed that bi ∼ N(0,σb). Significance codes: 0 ≤ “***” < 0.001 < “**” < 0.01 < “*” < 0.05 < “.” < 0.1 < “” ≤ 1.