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Mechanomyographic amplitude and mean power output during maximal, concentric, isokinetic muscle actions
Author(s) -
Cramer Joel T.,
Housh Terry J.,
Johnson Glen O.,
Ebersole Kyle T.,
Perry Sharon R.,
Bull Anthony J.
Publication year - 2000
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/1097-4598(200012)23:12<1826::aid-mus5>3.0.co;2-7
Subject(s) - concentric , vastus medialis , amplitude , electromyography , physics , quadriceps femoris muscle , mathematics , anatomy , vastus lateralis muscle , medicine , physical medicine and rehabilitation , isometric exercise , geometry , skeletal muscle , optics
The purpose of this study was to determine the velocity‐related patterns for mechanomyographic (MMG) amplitude, electromyographic (EMG) amplitude, mean power output (MP), and peak torque (PT) of the superficial muscles of the quadriceps femoris (vastus lateralis [VL], rectus femoris [RF], and vastus medialis [VM]) during maximal, concentric, isokinetic leg extensions. Twelve adult women (mean ± SD: 22 ± 3 years of age) performed such leg extensions at velocities of 60°, 120°, 180°, 240°, and 300°/s on a Cybex 6000 dynamometer. PT decreased ( P < 0.05) across velocity to 240°/s. MP and MMG amplitude for each muscle (VL, RF, and VM) increased ( P < 0.05) with velocity to 240°/s and then plateaued. EMG amplitude increased ( P < 0.05) to 240°/s for the VL, remained unchanged across velocity ( P > 0.05) for the RF, and increased ( P < 0.05) to 300°/s for the VM. The results indicated close similarities between the velocity‐related patterns for MMG amplitude and MP, but dissociations among EMG amplitude, MMG amplitude, and PT. These findings support the recent hypothesis that MMG amplitude is more closely related to MP than PT during maximal, concentric, isokinetic muscle actions and, therefore, may be useful for monitoring training‐induced changes in muscle power. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 1826–1831, 2000