title: Which type of repetitive muscle contractions induces a greater acute impairment of position sense?
abstract: The objective of this study was to determine which type of repetitive muscle contractions induces a greater acute impairment of elbow position sense. Eleven male subjects participating in the study underwent (i) an exercise task (ET) consisting of 9 sets of 10 voluntary isometric, concentric, or eccentric contractions randomly performed on three separate sessions, and (ii) a pre- and post-exercise maximal voluntary isometric contraction (iMVC). Prior to and between sets of ET, a proprioception task (PT) consisting of matching the right arm to the left reference arm was performed at three different target angular positions (70 degrees , 110 degrees and 150 degrees). Each ET was immediately followed by 3 PT and 1 min rest. The statistical analysis revealed that post-exercise iMVCs were significantly decreased compared to pre-exercise iMVC in all conditions with a greater drop following the eccentric task. Despite this greater drop, position sense was significantly affected by the concentric exercise task. In addition, the spectral EMG signals significantly shifted towards lower frequencies from the initial values, regardless of exercise task. The results showed that concentric muscle contractions impaired position sense to a greater extent compared to isometric and eccentric contractions.
authors.affiliation: School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada. sfortier@mun.ca
authors.forename: Sylvie
authors.initials: S
authors.lastname: Fortier
authors.forename: Fabien A
authors.initials: FA
authors.lastname: Basset
authors.forename: François
authors.initials: F
authors.lastname: Billaut
authors.forename: David
authors.initials: D
authors.lastname: Behm
authors.forename: Normand
authors.initials: N
authors.lastname: Teasdale
mesh_terms: D000328:Adult; D004551:Elbow Joint / Q000502:physiology; D006801:Humans; D007699:Kinesthesis / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D013647:Task Performance and Analysis