Muscle volume vs. anatomical cross-sectional area: Different muscle assessment does not affect the muscle size-strength relationship

Marcel B Lanza; Hugo C Martins-Costa; Carolina C De Souza; Fernando V Lima; Rodrigo C R Diniz; Mauro H Chagas

doi:10.1016/j.jbiomech.2022.110956

Muscle volume vs. anatomical cross-sectional area: Different muscle assessment does not affect the muscle size-strength relationship

J Biomech. 2022 Feb:132:110956. doi: 10.1016/j.jbiomech.2022.110956. Epub 2022 Jan 11.

Authors

Marcel B Lanza¹, Hugo C Martins-Costa², Carolina C De Souza³, Fernando V Lima⁴, Rodrigo C R Diniz⁴, Mauro H Chagas⁴

Affiliations

¹ Department of Physical Therapy and Rehabilitation, School of Medicine, University of Maryland, Baltimore, United States.
² Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil; Department of Physical Education, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Electronic address: hugocmc@gmail.com.
³ Department of Physical Education, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
⁴ Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil.

PMID: 35033973
DOI: 10.1016/j.jbiomech.2022.110956

Abstract

Muscle volume (MV) and anatomical cross-sectional area (CSA) are used as measures of muscle-size, but determining these from magnetic resonance imaging (MRI) is a very time-consuming process. Additionally, it is unclear if the use of different muscle size assessments (all vs. reduced number of slices images) would impact the muscle size-strength relationship. Thus, this study aimed to investigate if muscle size calculation by using a reduced or all slices images from pectoralis major (PM) would maintain a similar muscle size-strength relationship with bilateral maximal dynamic and isometric contractions on a bench press exercise. Twenty-four healthy males underwent an MRI examination to measure PM muscle size, and maximal isometric and dynamic contractions (by one repetition maximum, 1RM) were performed. Correlations between maximal isometric voluntary force (MVF) and dynamic strength (1RM) with muscle size variables [three images from the largest part of PM (CSA_3MAX), three images accounting for the shape -first image, middle image, final image- of the PM (CSA₃), and MV] were performed. The correlation between 1RM with MV, CSA₃, and CSA_3MAX were 0.84, 0.832, and 0.727 (p < 0.001), respectively. The correlation between MVF with MV, CSA₃, and CSA_3MAX were 0.738, 0.733, and 0.604 (p < 0.001), respectively. Overall, PM MV and CSA₃ exhibit a stronger and similar muscle size-strength relationship during maximal dynamic and isometric tests than CSA_3MAX. Therefore, a reduced number of slices (CSA₃) could be used as an alternative to considerably reduce the time of analysis without compromise muscle size-strength relationship.

Keywords: Anatomical cross-sectional area; Magnetic resonance imaging; Muscle size strength relationship; Muscle volume.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Exercise
Humans
Isometric Contraction / physiology
Male
Muscle Strength* / physiology
Muscle, Skeletal* / diagnostic imaging
Muscle, Skeletal* / physiology
Pectoralis Muscles