Moment arm-angle functions (MA-a-functions) are commonly used to estimate in vivo muscle forces in humans. However, different MA-a-functions might not only influence the magnitude of the estimated muscle forces but also change the shape of the muscle's estimated force-angle relationship (F-a-r). Therefore, we investigated the influence of different literature based Achilles tendon MA-a-functions on the triceps surae muscle--tendon unit F-a-r. The individual in vivo triceps torque--angle relationship was determined in 14 participants performing maximum voluntary fixed-end plantarflexion contractions from 18.3°þinspace±þinspace3.2° plantarflexion to 24.2°þinspace±þinspace5.1° dorsiflexion on a dynamometer. The resulting F-a-r were calculated using 15 literature-based in vivo Achilles tendon MA-a-functions. MA-a-functions affected the F-a-r shape and magnitude of estimated peak active triceps muscle--tendon unit force. Depending on the MA-a-function used, the triceps was solely operating on the ascending limb (nþinspace=þinspace2), on the ascending limb and plateau region (nþinspace=þinspace12), or on the ascending limb, plateau region and descending limb of the F-a-r (nþinspace=þinspace1). According to our findings, the estimated triceps muscle--tendon unit forces and the shape of the F-a-r are highly dependent on the MA-a-function used. As these functions are affected by many variables, we recommend using individual Achilles tendon MA-a-functions, ideally accounting for contraction intensity-related changes in moment arm magnitude.
%0 Journal Article
%1 Holzer2020
%A Holzer, Denis
%A Paternoster, Florian Kurt
%A Hahn, Daniel
%A Siebert, Tobias
%A Seiberl, Wolfgang
%D 2020
%J Scientific Reports
%K Far TS angle corresponding estimation force joint maximum muscle of on range the working
%N 1
%P 19559
%R 10.1038/s41598-020-76625-x
%T Considerations on the human Achilles tendon moment arm for in vivo triceps surae muscle--tendon unit force estimates
%U https://doi.org/10.1038/s41598-020-76625-x
%V 10
%X Moment arm-angle functions (MA-a-functions) are commonly used to estimate in vivo muscle forces in humans. However, different MA-a-functions might not only influence the magnitude of the estimated muscle forces but also change the shape of the muscle's estimated force-angle relationship (F-a-r). Therefore, we investigated the influence of different literature based Achilles tendon MA-a-functions on the triceps surae muscle--tendon unit F-a-r. The individual in vivo triceps torque--angle relationship was determined in 14 participants performing maximum voluntary fixed-end plantarflexion contractions from 18.3°þinspace±þinspace3.2° plantarflexion to 24.2°þinspace±þinspace5.1° dorsiflexion on a dynamometer. The resulting F-a-r were calculated using 15 literature-based in vivo Achilles tendon MA-a-functions. MA-a-functions affected the F-a-r shape and magnitude of estimated peak active triceps muscle--tendon unit force. Depending on the MA-a-function used, the triceps was solely operating on the ascending limb (nþinspace=þinspace2), on the ascending limb and plateau region (nþinspace=þinspace12), or on the ascending limb, plateau region and descending limb of the F-a-r (nþinspace=þinspace1). According to our findings, the estimated triceps muscle--tendon unit forces and the shape of the F-a-r are highly dependent on the MA-a-function used. As these functions are affected by many variables, we recommend using individual Achilles tendon MA-a-functions, ideally accounting for contraction intensity-related changes in moment arm magnitude.
@article{Holzer2020,
abstract = {Moment arm-angle functions (MA-a-functions) are commonly used to estimate in vivo muscle forces in humans. However, different MA-a-functions might not only influence the magnitude of the estimated muscle forces but also change the shape of the muscle's estimated force-angle relationship (F-a-r). Therefore, we investigated the influence of different literature based Achilles tendon MA-a-functions on the triceps surae muscle--tendon unit F-a-r. The individual in vivo triceps torque--angle relationship was determined in 14 participants performing maximum voluntary fixed-end plantarflexion contractions from 18.3{\textdegree}{\thinspace}{\textpm}{\thinspace}3.2{\textdegree} plantarflexion to 24.2{\textdegree}{\thinspace}{\textpm}{\thinspace}5.1{\textdegree} dorsiflexion on a dynamometer. The resulting F-a-r were calculated using 15 literature-based in vivo Achilles tendon MA-a-functions. MA-a-functions affected the F-a-r shape and magnitude of estimated peak active triceps muscle--tendon unit force. Depending on the MA-a-function used, the triceps was solely operating on the ascending limb (n{\thinspace}={\thinspace}2), on the ascending limb and plateau region (n{\thinspace}={\thinspace}12), or on the ascending limb, plateau region and descending limb of the F-a-r (n{\thinspace}={\thinspace}1). According to our findings, the estimated triceps muscle--tendon unit forces and the shape of the F-a-r are highly dependent on the MA-a-function used. As these functions are affected by many variables, we recommend using individual Achilles tendon MA-a-functions, ideally accounting for contraction intensity-related changes in moment arm magnitude.},
added-at = {2022-07-19T11:10:29.000+0200},
author = {Holzer, Denis and Paternoster, Florian Kurt and Hahn, Daniel and Siebert, Tobias and Seiberl, Wolfgang},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2dda7c7842f8b627c739b615bde678e28/inspo5},
day = 11,
doi = {10.1038/s41598-020-76625-x},
interhash = {12a4bf98a06f2d283088a3622f5e5b0d},
intrahash = {dda7c7842f8b627c739b615bde678e28},
issn = {2045-2322},
journal = {Scientific Reports},
keywords = {Far TS angle corresponding estimation force joint maximum muscle of on range the working},
month = nov,
number = 1,
pages = 19559,
timestamp = {2022-07-19T09:10:56.000+0200},
title = {Considerations on the human Achilles tendon moment arm for in vivo triceps surae muscle--tendon unit force estimates},
url = {https://doi.org/10.1038/s41598-020-76625-x},
volume = 10,
year = 2020
}
