Physiology

ABSTRACT

Background: Skeletal muscle (SM) is a large body compartment

of biological importance, but it remains difficult to quantify SM

with affordable and practical methods that can be applied in clinical

and field settings.

Objective: The objective of this study was to develop and

cross-validate anthropometric SM mass prediction models in

healthy adults.

Design: SM mass, measured by using whole-body multislice

magnetic resonance imaging, was set as the dependent variable

in prediction models. Independent variables were organized into

2 separate formulas. One formula included mainly limb circumferences

and skinfold thicknesses [model 1: height (in m) and

skinfold-corrected upperarm, thigh, and calf girths (CAG, CTG,

and CCG, respectively; in cm)]. The other formula included

mainly body weight (in kg) and height (model 2). The models

were developed and cross-validated in nonobese adults [body

mass index (in kg/m2) < 30].

Results: Two SM (in kg) models for nonobese subjects (n = 244)

were developed as follows: SM = Ht  (0.00744  CAG2 +

0.00088  CTG2 + 0.00441  CCG2) + 2.4  sex  0.048  age

+ race + 7.8, where R2 = 0.91, P < 0.0001, and SEE = 2.2 kg;

sex = 0 for female and 1 for male, race = 2.0 for Asian, 1.1 for

African American, and 0 for white and Hispanic, and SM = 0.244

 BW + 7.80  Ht + 6.6  sex  0.098  age + race  3.3,

where R2 = 0.86, P < 0.0001, and SEE = 2.8 kg; sex = 0 for female

and 1 for male, race = 1.2 for Asian, 1.4 for African American,

and 0 for white and Hispanic.

Conclusion: These 2 anthropometric prediction models, the first

developed in vivo by using state-of-the-art body-composition

methods, are likely to prove useful in clinical evaluations and

field studies of SM mass in nonobese adults. Am J Clin Nutr

2000;72:796–803.

KEY WORDS Limb circumference, skinfold thickness,

body composition, skeletal muscle, nonobese adults

INTRODUCTION

Although skeletal muscle (SM) makes up the largest fraction

of...