Premium
Effects of fatigue on electromechanical delay in human skeletal muscle: new insights from an electromyographic and mechanomyographic combined approach
Author(s) -
Esposito Fabio,
Cè Emiliano,
Rampichini Susanna,
Limonta Eloisa,
Veicsteinas Arsenio
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1078.11
Subject(s) - tendon , intraclass correlation , electromyography , biomedical engineering , electrical impedance myography , medicine , physical medicine and rehabilitation , cardiology , anatomy , clinical psychology , vasodilation , psychometrics
While tendons are the major contributor to the electromechanical delay (EMD, the latency between the onset of electrical activity and force in a muscle), the relative role of action potential propagation and excitation‐contraction coupling is still undefined. The aim of the study was: (i) to assess the reliability of an electromyographic (EMG) and mechanomyographic (MMG) approach in partitioning EMD; and (ii) to evaluate the effect of fatigue on the muscle and tendon EMD components. Tetanic stimulations were delivered to the medial gastrocnemius of 24 subjects, before and after a fatiguing stimulation. On a different day, the study was repeated for reliability purposes. During contractions, EMG, MMG and force were recorded. EMD and delays between EMG and MMG (Δt EMG‐MMG, muscle component) and MMG and force (Δt MMG‐F, tendon component) were calculated. Intraclass correlation coefficient (ICC) was 0.892, 0.915 and 0.917 for EMD, Δt EMG‐MMG and Δt MMG‐F, respectively. With fatigue, peak force dropped (−26%; P<0.05) and EMD, Δt EMG‐MMG and Δt MMG‐F lengthened from 25.58±2.62 ms, 11.44±0.64 ms and 13.84±2.96 ms to 31.57±4.18 ms (+23%), 12.75±0.66 ms (+12%) and 18.98±4.44 ms (+39%), respectively (P<0.05). EMG‐MMG approach was a reliable tool to assess EMD components. Although fatigue had a stronger effect on EMD tendon component, also muscle component was significantly affected. (UNIMI PUR grant #12‐1‐5059281‐42)