File(s) under permanent embargo
Tonic-to-phasic shift of lumbo-pelvic muscle activity during 8 weeks of bed rest and 6-months follow up.
journal contribution
posted on 2007-07-01, 00:00 authored by Daniel Belavy, C A Richardson, S J Wilson, D Felsenberg, J RittwegerPrior motor control studies in unloading have shown a tonic-to-phasic shift in muscle activation, particularly in the short extensors. Tonic muscle activity is considered critical for normal musculoskeletal function. The shift from tonic-to-phasic muscle activity has not been systematically studied in humans in unloading nor at the lumbo-pelvic (LP) region. Ten healthy young male subjects underwent 8 wk of bed rest with 6-mo follow up as part of the "Berlin Bed-Rest Study." A repetitive knee movement model performed in the prone position is used to stimulate tonic holding LP muscle activity, as measured by superficial EMG. Tonic and phasic activation patterns were quantified by relative height of burst vs. baseline electromyographic linear-envelope signal components. Statistical analysis shows a shift toward greater phasic activity during bed rest and follow up (P < 0.001) with a significant interaction across muscles (P < 0.001) specifically affecting the short lumbar extensors. These changes appear unrelated to skill acquisition over time (P all > or = 0.196). This change of a shift from tonic LP muscle activation to phasic is in line with prior research on the effects of reduced weight bearing on motor control.
History
Journal
Journal of Applied PhysiologyVolume
103Issue
1Pagination
48 - 54Publisher
American Physiological SocietyLocation
Bethesda, MdPublisher DOI
ISSN
8750-7587Language
engCopyright notice
2007, American Physiological SocietyUsage metrics
Categories
No categories selectedKeywords
Bed RestElectromyographyFollow-Up StudiesHumansKnee JointLumbosacral RegionMaleMotor SkillsMuscle ContractionMuscle, SkeletalMuscular DiseasesPelvisReproducibility of ResultsSpace FlightTime FactorsWeight-BearingScience & TechnologyLife Sciences & BiomedicinePhysiologySport Sciencesunloadingmotor controllumbar spineBerlin Bed-Rest StudyISOMETRIC AXIAL ROTATIONLUMBAR BACK MUSCLESTRUNK MUSCLESMICROGRAVITY ENVIRONMENTSPINDLE CONCENTRATIONSPARALLEL COMBINATIONSSKELETAL-MUSCLETRICEPS SURAEHIP EXTENSOREMG ACTIVITY
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC