%0 Journal Article %1 Christensen2021 %A Christensen, Kasper B. %A Günther, Michael %A Schmitt, Syn %A Siebert, Tobias %D 2021 %E Siebert, Tobias %J Scientific Reports %K Animal Bioenergetics Biomechanics Nonlinear behaviour dynamics %N 1 %P 23638 %R 10.1038/s41598-021-02819-6 %T Cross-bridge mechanics estimated from skeletal muscles' work-loop responses to impacts in legged locomotion %U https://doi.org/10.1038/s41598-021-02819-6 %V 11 %X Legged locomotion has evolved as the most common form of terrestrial locomotion. When the leg makes contact with a solid surface, muscles absorb some of the shock-wave accelerations (impacts) that propagate through the body. We built a custom-made frame to which we fixated a rat (Rattus norvegicus, Wistar) muscle (m. gastrocnemius medialis and lateralis: GAS) for emulating an impact. We found that the fibre material of the muscle dissipates between 3.5 and \$\$23\backslash,\backslashupmu \backslashhbox \J\\$\$ranging from fresh, fully active to passive muscle material, respectively. Accordingly, the corresponding dissipated energy in a half-sarcomere ranges between 10.4 and \$\$68\backslash,z\backslashhbox \J\\$\$, respectively. At maximum activity, a single cross-bridge would, thus, dissipate 0.6\% of the mechanical work available per ATP split per impact, and up to 16\% energy in common, submaximal, activities. We also found the cross-bridge stiffness as low as \$\$2.2\backslash,\backslashhbox \pN\\backslash,\backslashhbox \nm\^\-1\\$\$, which can be explained by the Coulomb-actuating cross-bridge part dominating the sarcomere stiffness. Results of the study provide a deeper understanding of contractile dynamics during early ground contact in bouncy gait.

@article{Christensen2021, abstract = {Legged locomotion has evolved as the most common form of terrestrial locomotion. When the leg makes contact with a solid surface, muscles absorb some of the shock-wave accelerations (impacts) that propagate through the body. We built a custom-made frame to which we fixated a rat (Rattus norvegicus, Wistar) muscle (m. gastrocnemius medialis and lateralis: GAS) for emulating an impact. We found that the fibre material of the muscle dissipates between 3.5 and {\$}{\$}23{\backslash},{\backslash}upmu {\backslash}hbox {\{}J{\}}{\$}{\$}ranging from fresh, fully active to passive muscle material, respectively. Accordingly, the corresponding dissipated energy in a half-sarcomere ranges between 10.4 and {\$}{\$}68{\backslash},z{\backslash}hbox {\{}J{\}}{\$}{\$}, respectively. At maximum activity, a single cross-bridge would, thus, dissipate 0.6{\%} of the mechanical work available per ATP split per impact, and up to 16{\%} energy in common, submaximal, activities. We also found the cross-bridge stiffness as low as {\$}{\$}2.2{\backslash},{\backslash}hbox {\{}pN{\}}{\backslash},{\backslash}hbox {\{}nm{\}}^{\{}-1{\}}{\$}{\$}, which can be explained by the Coulomb-actuating cross-bridge part dominating the sarcomere stiffness. Results of the study provide a deeper understanding of contractile dynamics during early ground contact in bouncy gait.}, added-at = {2022-07-19T11:10:29.000+0200}, author = {Christensen, Kasper B. and G{\"u}nther, Michael and Schmitt, Syn and Siebert, Tobias}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/21c85bdf11cbecb538cd5edf98a8597dd/inspo5}, day = 08, doi = {10.1038/s41598-021-02819-6}, editor = {Siebert, Tobias}, interhash = {043bc2c5e9b044a62a58167156c7fcb0}, intrahash = {1c85bdf11cbecb538cd5edf98a8597dd}, issn = {2045-2322}, journal = {Scientific Reports}, keywords = {Animal Bioenergetics Biomechanics Nonlinear behaviour dynamics}, month = dec, number = 1, pages = 23638, timestamp = {2022-07-19T09:10:56.000+0200}, title = {Cross-bridge mechanics estimated from skeletal muscles' work-loop responses to impacts in legged locomotion}, url = {https://doi.org/10.1038/s41598-021-02819-6}, volume = 11, year = 2021 }