title: Time course of central and peripheral alterations after isometric neuromuscular electrical stimulation-induced muscle damage.
abstract: Isometric contractions induced by neuromuscular electrostimulation (NMES) have been shown to result in a prolonged force decrease but the time course of the potential central and peripheral factors have never been investigated. This study examined the specific time course of central and peripheral factors after isometric NMES-induced muscle damage. Twenty-five young healthy men were subjected to an NMES exercise consisting of 40 contractions for both legs. Changes in maximal voluntary contraction force of the knee extensors (MVC), peak evoked force during double stimulations at 10 Hz (Db(10)) and 100 Hz (Db(100)), its ratio (10:100), voluntary activation, muscle soreness and plasma creatine kinase activity were assessed before, immediately after and throughout four days after NMES session. Changes in knee extensors volume and T2 relaxation time were also assessed at two (D2) and four (D4) days post-exercise. MVC decreased by 29% immediately after NMES session and was still 19% lower than the baseline value at D4. The decrease in Db(10) was higher than in Db(100) immediately and one day post-exercise resulting in a decrease (-12%) in the 10:100 ratio. On the contrary, voluntary activation significantly decreased at D2 (-5%) and was still depressed at D4 (-5%). Muscle soreness and plasma creatine kinase activity increased after NMES and peaked at D2 and D4, respectively. T2 was also increased at D2 (6%) and D4 (9%). Additionally, changes in MVC and peripheral factors (e.g., Db(100)) were correlated on the full recovery period, while a significant correlation was found between changes in MVC and VA only from D2 to D4. The decrease in MVC recorded immediately after the NMES session was mainly due to peripheral changes while both central and peripheral contributions were involved in the prolonged force reduction. Interestingly, the chronological events differ from what has been reported so far for voluntary exercise-induced muscle damage.
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Fouré
authors.affiliation: Edith Cowan University, School of Exercise and Health Sciences, WA 6027, Joondalup, Australia.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nosaka
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Wegrzyk
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Duhamel
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Le Troter
authors.affiliation: APHM, La Timone Hospital, CEMEREM, Imaging Center, Marseille, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Boudinet
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France; APHM, La Conception Hospital, Department of Rheumatology, Marseille, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Mattei
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Vilmen
authors.affiliation: University of Nantes, Laboratory "Motricité, Interactions, Performance" (EA 4334), UFR STAPS, Nantes, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Jubeau
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: David
authors.initials: D
authors.lastname: Bendahan
authors.affiliation: Aix-Marseille University, CNRS, CRMBM UMR CNRS 7339, Marseille, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Gondin
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D015444:Exercise; D006801:Humans; D007537:Isometric Contraction; D007717:Knee / Q000503:physiopathology; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue / Q000502:physiology; D009468:Neuromuscular Diseases / Q000503:physiopathology / Q000628:therapy*