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Effect of moderate dehydration on torque, electromyography, and mechanomyography
Author(s) -
Evetovich Tammy K.,
Boyd Joseph C.,
Drake Shawn M.,
Eschbach Lawrence C.,
Magal Meir,
Soukup Jeffrey T.,
Webster Michael J.,
Whitehead Malcolm T.,
Weir Joseph P.
Publication year - 2002
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/mus.10203
Subject(s) - isometric exercise , electromyography , concentric , biceps , dehydration , biceps brachii muscle , torque , analysis of variance , electrophysiology , biomedical engineering , medicine , anatomy , physical medicine and rehabilitation , chemistry , mathematics , physics , biochemistry , geometry , thermodynamics
The purpose of the present investigation was to test the hypotheses that the mechanomyographic (MMG) signal would be affected by hydration status due to changes in the intra‐ and extracellular fluid content (which could affect the degree of fluid turbulence), changes in the filtering properties of the tissues between the MMG sensor and muscle, and changes in torque production that may accompany dehydration. Ten subjects (age 22.5 ± 1.6 years) were tested for maximal isometric (MVC), submaximal isometric (25, 50, and 75%MVC), and maximal concentric isokinetic muscle strength of the biceps brachii in either a euhydrated or dehydrated state while the electromyographic (EMG) and MMG signals were recorded. Separate three‐way and two‐way ANOVAs indicated no change in torque, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF with dehydration. The lack of dehydration effect suggests that MMG may be more reflective of the intrinsic contractile processes of a muscle fiber (torque production) or the motor control mechanisms (reflected by the EMG) than the tissues and fluids surrounding the muscle fiber. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 225–231, 2002