PreprintArticleVersion 1Preserved in Portico This version is not peer-reviewed
How to Confuse Motor Control: Passive Muscle Shortening Af-ter Contraction in Lengthened Position Reduces the Muscular Hold-ing Stability in the Sense of Adaptive Force
Version 1
: Received: 28 February 2023 / Approved: 6 March 2023 / Online: 6 March 2023 (09:50:47 CET)
How to cite:
Bittmann, F.N.; Dech, S.; Schaefer, L.V. How to Confuse Motor Control: Passive Muscle Shortening Af-ter Contraction in Lengthened Position Reduces the Muscular Hold-ing Stability in the Sense of Adaptive Force. Preprints2023, 2023030101. https://doi.org/10.20944/preprints202303.0101.v1.
Bittmann, F.N.; Dech, S.; Schaefer, L.V. How to Confuse Motor Control: Passive Muscle Shortening Af-ter Contraction in Lengthened Position Reduces the Muscular Hold-ing Stability in the Sense of Adaptive Force. Preprints 2023, 2023030101. https://doi.org/10.20944/preprints202303.0101.v1.
Cite as:
Bittmann, F.N.; Dech, S.; Schaefer, L.V. How to Confuse Motor Control: Passive Muscle Shortening Af-ter Contraction in Lengthened Position Reduces the Muscular Hold-ing Stability in the Sense of Adaptive Force. Preprints2023, 2023030101. https://doi.org/10.20944/preprints202303.0101.v1.
Bittmann, F.N.; Dech, S.; Schaefer, L.V. How to Confuse Motor Control: Passive Muscle Shortening Af-ter Contraction in Lengthened Position Reduces the Muscular Hold-ing Stability in the Sense of Adaptive Force. Preprints 2023, 2023030101. https://doi.org/10.20944/preprints202303.0101.v1.
Abstract
Adaptation to external forces relies on a well-functioning proprioceptive system including muscle spindle afferents. Muscle length-tension control in reaction to external forces is most important regarding the Adaptive Force (AF). This study investigated the effect of different procedures, which are assumed to influence the function of muscle spindles, on the AF. 19 elbow flexors of 12 healthy participants were assessed by an objectified manual muscle test (MMT) with different procedures: regular MMT, MMT after pre-contraction (self-estimated 20% MVIC) in lengthened position with passive return to test position (CL) and MMT after CL with a second pre-contraction in test position (CL-CT). During regular MMTs, muscles maintained their length up to 99.7±1.0% of the maximal AF (AFmax). After CL, muscles started to lengthen at 53.0±22.5% of AFmax. For CL-CT, muscles were again able to maintain the isometric position up to 98.3±5.5% of AFmax. AFisomax differed highly significantly between CL vs. CL-CT and regular MMT. CL is assumed to generate a slack of muscle spindles which led to a substantial reduction of the holding capacity. This was immediately erased by a pre-contraction in test position. The results substantiate that muscle spindle sensitivity seems to play an important role for neuromuscular functioning and musculoskeletal stability.
Copyright:
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.
