Corrigendum to “Comparative Sensitivity Analysis of Muscle Activation Dynamics”

We provide a comment to our paper “Comparative Sensitivity Analysis of Muscle Activation Dynamics,” Computational and Mathematical Methods in Medicine (2015), 16 pages, Article ID 585409, DOI 10.1155/2015/585409 [1], where we stated an erroneous form of Hatze’s activation dynamics that is not applicable to non-steady-state muscle processes. However, as we only considered steady-state situations, all results and consequences still hold true. The authors would like to apologize for any inconvenience caused.

In his consecutive work [2–4], Hatze introduced the dynamics of changes in activity (activation dynamics) for skeletal muscle fibers in response to neural stimulation as a multilevel process, with being the relative free calcium ion concentration and the length of the contractile element (CE). In [4, Eqns. , , and ], this process is summarized as follows:

In our main article [1, Eqn. ], we had reformulated the above equation system (1) as in an effort to eliminate the state variable in favor of . However, the specific formulation in (2) holds only true in the steady-state case . This is because the transformation [5, Eqns. –] was erroneously done by rather than properly taking the total derivativefor the total time derivative of .

In our framework only steady-state muscle conditions were investigated; that is, , such that the second term of the right hand side in (4) vanishes. Hence, the situation from (2) holds throughout the article. In non-steady-state isometric contractions, this second term seems to be of reversed sign to the first, but with a considerably smaller absolute value; compare [6].

Acknowledgments

The authors would like to thank Maria Hammer for drawing attention to their computational error.

References

1. R. Rockenfeller, M. Günther, S. Schmitt, and T. Götz, “Comparative sensitivity analysis of muscle activation dynamics,” Computational and Mathematical Methods in Medicine, vol. 2015, Article ID 585409, 2015. View at: Publisher Site | Google Scholar
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6. R. Rockenfeller and M. Günther, “Extracting low-velocity concentric and eccentric dynamic muscle properties from isometric contraction experiments,” Mathematical Biosciences, vol. 278, pp. 77–93, 2016. View at: Publisher Site | Google Scholar | MathSciNet

Copyright

Copyright © 2017 Robert Rockenfeller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.