# Erratum

This page describes the errors found in our book. Please let us know if you find any error and I promise 5£ or a beer/lime juice next time we meet for each significant error (e.g. an error in a mathematical formula, an error in a citation of your work, a wrong interpretation).

List of errors:

1. At page 16, the following sentence could be deleted (as the CNS is defined just 3 lines before): "Together, the neurons in the brain, brainstem, and spinal cord constitute the CNS."

2. On page 50 in the caption of figure 3.8. Slow twitch should be type I and fast twitch type II.

3. On page 61, in both equations 4.5 and 4.6, in the last term of the first line, a - sign should be added to the denominator before \lambda_- (as in the next equality of each of these equations).

3. In equation 5.12 on page 89, the \rho should be bold, as it is the vector of moment arms.

4. On page 86, in figure 5.3, this should be triceps lateralis, not lateralus.

5. In equation 5.17 on page 93, after the second =, the partial derivative symbol is missing in the denominator.

6. On page 100, in equations 5.25 and 5.26: l_se should be l_e and l_sew should be l_w.

7. On page 101, equation 5.30: q* should be the time derivative \dot{q}*.

8. In Table 2 page 107, the unit of length is [m], not [cm].

9. Equation 6.5 on page 113: brackets are missing on the right, i.e. it should be J^T(F_E - \Delta F_E). Similarly, after equation 6.6 it should be J^T \Delta F_E.

10. On page 117, about d'Avella et al. paper on synergies in reaching movements:

"Three phasic synergies scaled linearly with the movement duration, in a manner similar to equation (6.13), although we would have expected a quadratic relation as muscle activation corresponds roughly to force."

should be replaced by:

"Three phasic synergies scaled with the movement duration in a manner similar to equation (6.13)."

11. On page 112, there are several errors in the formulae of equations (6.3,6.4):

- One sign error in the C term of equation (6.3)

- Several errors in the components of the \Psi matrix of equation (6.4). The correct equations are described in this .pdf

12. On page 120, equation 6.16: The denominator should be square rooted (as in Tee et al, 2004, equ.4).

13. Figure 6.4C page 121: the time scale should indicate 1s, 2s (not 0.1s, 0.2s).

14. On page 148, In the sentence following equation 7.6, all x should be z.

15. Figure 9.3, page 192: C <-> D; change the references to this figure in the text at page 192 correspondingly.

16. Page 197, after equation 9.12: it should be E[z_k z_k^T] and E[y_k y_k^T], not E(z_k z_k^T) and E(y_k y_k^T). (and the formatting of equation 9.12 has some problem in the middle line).

17. Page 223, in Figure 10.4, it should be "discrepancy", not "discrepency".

18. Page 252: it should be J_{μ}(ρ), not J_{μ}(q).