Time-of-day effect on patella tendon stiffness alters vastus lateralis fascicle length but not the quadriceps force-angle relationship

Onambele-Pearson, G and Pearson, S ORCID: https://orcid.org/0000-0003-1503-5452 2007, 'Time-of-day effect on patella tendon stiffness alters vastus lateralis fascicle length but not the quadriceps force-angle relationship' , Journal of Biomechanics, 40 (5) , pp. 1031-1037.

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Abstract

Aim: To examine the time-of-day (TOD) effect on torque–force/angle, fibre length (FL), tendon stiffness (K), stress, and strain using the quadriceps muscle–tendon complex as a model. Methods: Twelve healthy young men (aged 27±2.0 years) were studied at AM (7h45) and PM (5h45). Maximal isometric contractions were carried out on an isokinetic dynamometer, with real-time recordings of vastus lateralis (VL) FL and patella tendon K using B-mode ultrasonography. Percutaneous electrical twitch doublets superimposed on maximal torque were used to test for muscle activation capacity (AC). Results: At PM, torque and force increased by 16±3.0% (P<0.01) over 30–90° knee angles. Where the load was standardised (at 250 N) in order to discriminate between torque generation capacity and tendon K changes, PM relative to AM, there were 8% and 13% (P<0.01) reductions in relaxed and contracted FL, respectively. Average K decreased by 21% (P<0.001) and the maximal stress and strain were increased at PM by 11% and 16%, respectively (P<0.01). No TOD effect on AC was seen. Conclusion: The quadriceps torque or force–angle relationships shift upwards at PM vs. AM, with no shift in the position of the optimal knee angle. This torque or force increase appears not to be centrally modulated. Although K decreases with TOD thereby potentially shortening the working length of the sarcomeres, these changes overall do not affect the ability of the muscle to produce greater torque in the evening.

Item Type:	Article
Themes:	Health and Wellbeing
Schools:	Schools > School of Health and Society > Centre for Health Sciences Research
Journal or Publication Title:	Journal of Biomechanics
Publisher:	Elsevier
Refereed:	Yes
ISSN:	0021-9290
Related URLs:	Publication
Funders:	Prof T. Sargeant, Director of Biomove, Institute of Clinical and Biophysical Research into Human Movement
Depositing User:	S Pearson
Date Deposited:	06 Jul 2015 10:52
Last Modified:	04 Apr 2019 08:30
URI:	http://usir.salford.ac.uk/id/eprint/35075

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