Muscular-Metric Parameters.

Individual ML threshold, intercept and slope parameters ± SE obtained by Logit glm fit describing the percentage of muscular activation (namely, PoolEmg > criterion) as function of upward force level presentation. R2 emg values describe, per each subject, the explained variance of the Logit function used to account for the probability of PoolEmg > criterion at each force presented. An index of similarity (R2 merged) between the two metrics was defined as the goodness of fit of a Logit function explaining both perceptual and muscular probabilities merged together. Thus, R2 merged represents the level of concordance between muscular and perceptual performances in describing the subjects’ decision about upward forces. Participants 6 and 9 were excluded from further analysis since Logit function could not reliably explained their probability of pooled muscular activation over criterion (R2 ≈ 0). Similarly, subject 7 was excluded since his index of concordance between muscular activity and perceptual decisions was lower than 0.5.