title: Electrical and mechanical response of finger flexor muscles during voluntary isometric contractions in elite rock-climbers.
abstract: To determine the differences between rock-climbers and controls in finger flexor (FF) motor units (MUs) features and activation strategy, eleven climbers and ten controls volunteered for the study. After maximal voluntary contraction (MVC) assessment, five levels of isometric contractions at 20, 40, 60, 80 and 100% MVC were performed. During contractions, electromyogram (EMG) and mechanomyogram (MMG) were recorded, from which the root mean square (RMS) and mean frequency (MF) were calculated. Climbers showed significantly higher MVC. EMG RMS was statistically higher in climbers than in controls from 60 to 100% MVC. In climbers MMG RMS increased up to 80% MVC, whereas in controls it increased only up to 60% MVC. MMG MF was higher in climbers than in controls from 60 to 100% MVC (P < 0.05). EMG-MMG combined analysis revealed significant differences in MU activation strategy between the two groups. The results are compatible with a shift of climbers' muscles toward faster MUs.
authors.affiliation: Institute of Physical Exercise, Health and Sport, University of Milan, Via Colombo 71, 20133, Milan, Italy. fabio.esposito@unimi.it
authors.forename: Fabio
authors.initials: F
authors.lastname: Esposito
authors.forename: Eloisa
authors.initials: E
authors.lastname: Limonta
authors.forename: Emiliano
authors.initials: E
authors.lastname: Cè
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Gobbo
authors.forename: Arsenio
authors.initials: A
authors.lastname: Veicsteinas
authors.forename: Claudio
authors.initials: C
authors.lastname: Orizio
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography / Q000379:methods; D005542:Forearm / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D013177:Sports