Motor unit activation strategy during a sustained isometric contraction of finger flexor muscles in elite climbers

Eloisa Limonta, Emiliano Cè, Massimiliano Gobbo, Arsenio Veicsteinas, Claudio Orizio, Fabio Esposito

Research output: Contribution to journalArticlepeer-review

Abstract

The aim of the study was to evaluate, by an electromyographic (EMG) and mechanomyographic (MMG) combined approach, whether years of specific climbing activity induced neuromuscular changes towards performances related to a functional prevalence of fast resistant or fast fatigable motor units. For this purpose, after the maximum voluntary contraction (MVC) assessment, 11 elite climbers and 10 controls performed an exhaustive handgrip isometric effort at 80% MVC. Force, EMG and MMG signals were recorded from the finger flexor muscles during contraction. Time and frequency domain analysis of EMG and MMG signals was performed. In climbers: (i) MVC was higher (762 ± 34 vs 512 ± 57 N; effect size: 1.64; confidence interval: 0.65-2.63; P < 0.05); (ii) endurance time at 80% MVC was 43% longer (34.2 ± 3.7 vs 22.3 ± 1.5 s; effect size: 1.21; confidence interval: 0.28-2.14; P < 0.05); (iii) force accuracy and stability were greater during contraction (P < 0.05); (iv) EMG and MMG parameters were higher throughout the entire isometric effort (P < 0.05). Collectively, force, EMG and MMG combined analysis revealed that several years of specific climbing activity addressed the motor control system to adopt muscle activation strategies based on the functional prevalence of fast resistant motor units.

Original languageEnglish
Pages (from-to)133-142
Number of pages10
JournalJournal of Sports Sciences
Volume34
Issue number2
DOIs
Publication statusPublished - 2016

Keywords

  • electromyogram
  • handgrip
  • mechanomyogram
  • sport climbing

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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