A NONINVASIVE TEST FOR ESTIMATING TYPE I MYOSIN HEAVY CHAIN EXPRESSION IN WOMEN USING MECHANOMYOGRAPHY

Authors

SA Sontag
ME Parra
HL Dimmick
AJ Sterczala
JD Miller
JA Deckert
PM Gallagher
AC Fry
TJ Herda
MA Trevino

Abstract

Stephanie A. Sontag¹, Mandy E. Parra², Hannah L. Dimmick³, Adam J. Sterczala⁴, Jonathan D. Miller⁵, Jake A. Deckert⁶, Phillip M. Gallagher⁵, Andrew C. Fry⁵, Trent J. Herda⁵, and Michael A. Trevino¹

¹Oklahoma State University, Stillwater, OK; ²University of Mary Hardin-Baylor, Belton, TX; ³University of Calgary, Calgary, AB; ⁴University of Pittsburgh, Pittsburgh, PA; ⁵University of Kansas, Lawrence, KS; ⁶Gonzaga University, Spokane, WA

PURPOSE: To determine if mechanomyographic amplitude (MMG_RMS)-torque relationships can estimate type I percent myosin heavy chain expression (%MHC) of the vastus lateralis (VL) in sedentary women. METHODS: Fifteen healthy women (mean ± SD; age = 21.3 ± 5.3 yrs) volunteered for this study. Subjects performed 3 isometric maximal voluntary contractions (MVCs) of the knee extensors on an isokinetic dynamometer. The highest torque output determined the target torque levels for the subsequent randomly ordered isometric trapezoidal muscle actions at 30% and 70% MVC. An MMG sensor was placed on the VL. Simple linear regression models were fit to the log-transformed MMG_RMS-torque relationships for the linear increasing and decreasing segments. MMG_RMS was averaged for the steady torque segment. After testing, a muscle biopsy was taken from the VL. %MHC was analyzed with SDS-PAGE. Pearson’s product moment correlation coefficients determined relationships among type I %MHC expression and each MMG variable (6 total). Sequential multiple-regression procedures determined if a predictive model for type I %MHC of the VL could be developed with the MMG variables significantly correlated with type I %MHC. Alpha was set at 0.05. RESULTS: Type I %MHC was correlated with the b terms from the MMG_RMS-torque relationships for the linearly increasing segments at 70% MVC (p = 0.003; r = -0.72) and MMG_RMS for the steady torque segments at 30% (p = 0.008; r = -0.65) and 70% MVC (p = 0.040; r = -0.54). No other relationships existed (p > 0.05). For the regression model, correlated variables were added in order of significance. The addition of each variable significantly added to the model (p < 0.05) and overall accounted for 81.2% of the variance in type I %MHC (Table 1). CONCLUSION: MMG_RMS may provide a noninvasive method for estimating type I %MHC of the VL in untrained women. Future research should investigate the utility of this model in other populations.

Recommended Citation

Sontag, SA; Parra, ME; Dimmick, HL; Sterczala, AJ; Miller, JD; Deckert, JA; Gallagher, PM; Fry, AC; Herda, TJ; and Trevino, MA (2022) "A NONINVASIVE TEST FOR ESTIMATING TYPE I MYOSIN HEAVY CHAIN EXPRESSION IN WOMEN USING MECHANOMYOGRAPHY," International Journal of Exercise Science: Conference Proceedings: Vol. 11: Iss. 9, Article 14.
Available at: https://digitalcommons.wku.edu/ijesab/vol11/iss9/14