Task-Dependent Intermuscular Motor Unit Synchronization between Medial and Lateral Vastii Muscles during Dynamic and Isometric Squats

Simple item page
dc.contributor.authorMohr, Maurice
dc.contributor.authorNann, Marius
dc.contributor.authorvon Tschamer, Vinzenz
dc.contributor.authorEskofier, Bjoern
dc.contributor.authorNigg, Benno Maurus
dc.date.accessioned2016-01-05T23:24:07Z
dc.date.available2016-01-05T23:24:07Z
dc.date.issued2015-11-03
dc.description.abstractPurpose Motor unit activity is coordinated between many synergistic muscle pairs but the functional role of this coordination for the motor output is unclear. The purpose of this study was to investigate the short-term modality of coordinated motor unit activity–the synchronized discharge of individual motor units across muscles within time intervals of 5ms–for the Vastus Medialis (VM) and Lateralis (VL). Furthermore, we studied the task-dependency of intermuscular motor unit synchronization between VM and VL during static and dynamic squatting tasks to provide insight into its functional role. Methods Sixteen healthy male and female participants completed four tasks: Bipedal squats, single-leg squats, an isometric squat, and single-leg balance. Monopolar surface electromyography (EMG) was used to record motor unit activity of VM and VL. For each task, intermuscular motor unit synchronization was determined using a coherence analysis between the raw EMG signals of VM and VL and compared to a reference coherence calculated from two desynchronized EMG signals. The time shift between VM and VL EMG signals was estimated according to the slope of the coherence phase angle spectrum. Results For all tasks, except for singe-leg balance, coherence between 15–80Hz significantly exceeded the reference. The corresponding time shift between VM and VL was estimated as 4ms. Coherence between 30–60Hz was highest for the bipedal squat, followed by the single-leg squat and the isometric squat. Conclusion There is substantial short-term motor unit synchronization between VM and VL. Intermuscular motor unit synchronization is enhanced for contractions during dynamic activities, possibly to facilitate a more accurate control of the joint torque, and reduced during single-leg tasks that require balance control and thus, a more independent muscle function. It is proposed that the central nervous system scales the degree of intermuscular motor unit synchronization according to the requirements of the movement task at hand.en_US
dc.description.refereedYesen_US
dc.description.sponsorshipUniversity of Calgary Open Access Author's Funden_US
dc.identifier.citationMohr M, Nann M, von Tscharner V, Eskofier B, Nigg BM (2015) Task-Dependent Intermuscular Motor Unit Synchronization between Medial and Lateral Vastii Muscles during Dynamic and Isometric Squats. PLoS ONE 10(11): e0142048. doi: 10.1371/journal.pone.0142048en_US
dc.identifier.doi10.1371/journal.pone.0142048
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/34250
dc.identifier.urihttp://hdl.handle.net/1880/51053
dc.language.isoenen_US
dc.publisherPLoS ONEen_US
dc.publisher.departmentHuman Performance Laben_US
dc.publisher.facultyKinesiologyen_US
dc.publisher.institutionUniversity of Calgaryen_US
dc.publisher.urlhttp://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142048en_US
dc.rightsAttribution 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.subjectElectromyographyen_US
dc.subjectSignal processingen_US
dc.subjectMusculoskeletal mechanicsen_US
dc.subjectElectrodesen_US
dc.subjectMuscle functionsen_US
dc.subjectKneesen_US
dc.subjectMuscle contractionen_US
dc.subjectSignal filteringen_US
dc.titleTask-Dependent Intermuscular Motor Unit Synchronization between Medial and Lateral Vastii Muscles during Dynamic and Isometric Squatsen_US
dc.typejournal article
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
journal.pone.0142048.pdf
Size:
2.81 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.84 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Kinesiology Research & Publications