Relationship between physical activity time and intramuscular adipose tissue content of the thigh muscle groups of younger and older men

Madoka Ogawa,Teruhiko Koike,Yoshiharu Oshida,Akito Yoshiko,Noriko Tanaka,Hiroshi Akima

doi:10.1038/s41598-021-99126-x

Abstract

We investigated the effect of physical activity on muscle tissue size and intramuscular adipose tissue (IntraMAT) content in the thigh muscle groups of younger and older men. Twenty younger and 20 older men participated in this study. The muscle tissue cross-sectional area (CSA) and the IntraMAT content in the quadriceps femoris (QF), hamstrings (HM), hip adductors (AD), and mid-thigh total were measured using magnetic resonance imaging. The physical activity time was measured using a triaxial accelerometer, and four levels of physical activity were determined depending on the metabolic equivalent of task (METs), including sedentary (≤ 1.5 METs), light intensity (≤ 2.9 METs), moderate intensity (3.0–5.9 METs), and vigorous intensity (≥ 6.0 METs). No significant correlation was observed between the physical activity parameters and muscle tissue CSA in both groups. The IntraMAT content of the three muscle groups (QF, AD, and HM) and the total thigh was inversely correlated with the time of moderate-intensity physical activity (rs = − 0.625 to − 0.489, P < 0.05, for all comparisons) in the young group, but not in the older group. These results indicate that IntraMAT accumulation was associated with the amount of moderate-physical activity in younger men.

Highlights

We investigated the effect of physical activity on muscle tissue size and intramuscular adipose tissue (IntraMAT) content in the thigh muscle groups of younger and older men
Characteristic Age Height Body weight Body mass index Body fat (%) Muscle tissue cross-sectional area (CSA) quadriceps femoris (QF) AD HM Total IntraMAT content (%) QF AD HM Total intermuscular adipose tissue, which is adipose tissue located between muscle groups[5,6]
An epidemiological study showed that larger muscle cross-sectional area (CSA), lower muscle quality, and higher muscle strength were associated with a lower risk of mortality[11], suggesting that larger muscle size and lower IntraMAT content in older individuals are desirable to reduce the risk of mortality, insulin resistance and d iabetes[3]

Summary

Introduction

We investigated the effect of physical activity on muscle tissue size and intramuscular adipose tissue (IntraMAT) content in the thigh muscle groups of younger and older men. The IntraMAT content of the three muscle groups (QF, AD, and HM) and the total thigh was inversely correlated with the time of moderate-intensity physical activity (rs = − 0.625 to − 0.489, P < 0.05, for all comparisons) in the young group, but not in the older group These results indicate that IntraMAT accumulation was associated with the amount of moderate-physical activity in younger men. Abbreviations AD Hip adductors BMI Body mass index CSA Cross-sectional area HM Hamstrings ROI Region of interest LPA Light-intensity physical activity MET Metabolic equivalent of task MRI Magnetic resonance imaging MPA Moderate-intensity physical activity IMAT Intramuscular and intermuscular adipose tissues IntraMAT Intramuscular adipose tissue QF Quadriceps femoris VPA Vigorous-intensity physical activity. These previous findings suggest the importance of maintaining or increasing daily physical activity levels from the viewpoint of preventing IntraMAT accumulation

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