Prolonged Intermittent Trunk Flexion Increases Trunk Muscles Reflex Gains and Trunk Stiffness

DOI

The goal of the present study was to determine the effects of prolonged, intermittent flexion on trunk neuromuscular control. Furthermore, the potential beneficial effects of passive upper body support during flexion were investigated. Twenty one healthy young volunteers participated during two separate visits in which they performed 1 hour of intermittent 60 seconds flexion and 30 seconds rest cycles. Flexion was set at 80% lumbar flexion and was performed with or without upper body support. Before and after intermittent flexion exposure, lumbar range of motion was measured using inertial measurement units and trunk stability was assessed during perturbations applied in the forward direction with a force controlled actuator. Closed-loop system identification was used to determine the trunk translational admittance and reflexes as frequency response functions. The admittance describes the actuator displacement as a function of contact force and to assess reflexes muscle activation was related to actuator displacement. Trunk admittance gain decreased after unsupported flexion, while reflex gain and lumbar range of motion increased after both conditions. Significant interaction effects confirmed a larger increase in lumbar range of motion and reflex gains at most frequencies analysed following unsupported flexion in comparison to supported flexion, probably compensating for decreased passive tissue stiffness. In contrast with some previous studies we found that prolonged intermittent flexion decreased trunk admittance, which implies an increase of the lumped intrinsic and reflexive stiffness. This would compensate for decreased stiffness at the cost of an increase in cumulative low back load. Taking into account the differences between conditions it would be preferable to offer upper body support during activities that require prolonged trunk flexion.

The depositor supplied the files in .docx and .xlsx format. DANS added the .pdf/a format for the .docx files and the .csv format for each sheet of the .xlsx format in the map 'DANS added formats'.The PLoS ONE paper has been added to the dataset on 6 december 2016.

Identifier
DOI https://doi.org/10.17026/dans-xm5-ju54
Metadata Access https://lifesciences.datastations.nl/oai?verb=GetRecord&metadataPrefix=oai_datacite&identifier=doi:10.17026/dans-xm5-ju54
Provenance
Creator J.H. van Dieën
Publisher DANS Data Station Life Sciences
Contributor J.H. van Dieen; M. Voglar (University of Primorska, Andrej Marušič Institute, Koper, Slovenia); J. Wamerdam (MOVE Research Institute Amsterdam, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands); I . Kingma (MOVE Research Institute Amsterdam, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands); N. Sarabon (University of Primorska, Andrej Marušič Institute, Koper, Slovenia and S2P Ltd., Laboratory for Motor Control and Motor Learning, Ljubljana, Slovenia)
Publication Year 2016
Rights CC0 1.0; info:eu-repo/semantics/closedAccess; http://creativecommons.org/publicdomain/zero/1.0
OpenAccess false
Contact J.H. van Dieen (Vrije Universiteit Amsterdam)
Representation
Resource Type Dataset
Format application/vnd.openxmlformats-officedocument.wordprocessingml.document; application/pdf; application/zip; text/csv; application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Size 71855; 53092; 24501; 2211398; 11800; 12114; 74937; 1368; 43879; 57686; 100982; 113271; 73259
Version 2.0
Discipline Life Sciences; Medicine