Schmoll, M, Unger, E, Sutherland, H, Haller, M, Bijak, M, Lanmüller, H and Jarvis, JC (2017) In-situ measurements of tensile forces in the tibialis anterior tendon of the rat in concentric, isometric, and resisted co-contractions. Physiological Reports, 5 (8). ISSN 2051-817X
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Abstract
Tensile-force transmitted by the tibialis anterior (TA) tendon of 11 anesthetized adult male Wistar rats (body-mass: 360.6 ± 66.3 g) was measured in-situ within the intact biomechanical system of the hind-limb using a novel miniature in-line load-cell. The aim was to demonstrate the dependence of the loading-profile experienced by the muscle, on stimulation-frequency and the resistance to shortening in a group of control-animals. Data from these acute-experiments shows the type of loading achievable by means of implantable electrical stimulators activating agonists or agonist/antagonist groups of muscles during programmed resistance-training in freely moving healthy subjects. Force-responses to electrical stimulation of the common peroneal nerve for single pulses and short bursts were measured in unloaded and isometric contractions. A less time-consuming approach to measure the force-frequency relationship was investigated by applying single bursts containing a series of escalating stimulus-frequencies. We also measured the range of loading attainable by programmed co-contraction of the TA-muscle with the plantar-flexor muscles for various combinations of stimulation-frequencies. The maximal average peak-force of single twitches was 179% higher for isometric than for unloaded twitches. Average maximal isometric tetanic-force per gramme muscle-mass was 16.5 ± 3.0 N g(-1), which agrees well with other studies. The standard and time-saving approaches to measure the force-frequency relationship gave similar results. Plantar-flexor co-activation produced greatly increased tension in the TA-tendon, similar to isometric contractions. Our results suggest that unloaded contractions may not be adequate for studies of resistance-training. Plantar-flexor co-contractions produced considerably higher force-levels that may be better suited to investigate the physiology and cell-biology of resistance-training in rodents.
Item Type: | Article |
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Uncontrolled Keywords: | Antagonistic co‐contraction; in‐line force‐measurement; rat tibialis anterior |
Subjects: | Q Science > QP Physiology R Medicine > RC Internal medicine > RC1200 Sports Medicine |
Divisions: | Sport & Exercise Sciences |
Publisher: | Wiley Open Access |
Related URLs: | |
Date Deposited: | 02 May 2017 13:34 |
Last Modified: | 04 Sep 2021 11:39 |
DOI or ID number: | 10.14814/phy2.13245 |
URI: | https://researchonline.ljmu.ac.uk/id/eprint/6338 |
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