Relationship between Skeletal Muscle Thickness and Physical Activity in 4- to 6-Year-Olds in Japan

Pengyu Deng; Hayao Ozaki; Toshiharu Natsume; Yoshihiko Ishihara; Dandan Ke; Koya Suzuki; Hisashi Naito

doi:10.3390/children10030455

Relationship between Skeletal Muscle Thickness and Physical Activity in 4- to 6-Year-Olds in Japan

Children (Basel). 2023 Feb 25;10(3):455. doi: 10.3390/children10030455.

Authors

Pengyu Deng^{1

2}, Hayao Ozaki^{1

3}, Toshiharu Natsume⁴, Yoshihiko Ishihara^{1

5}, Dandan Ke^{1

6}, Koya Suzuki^{1

2}, Hisashi Naito^{1

2}

Affiliations

¹ Faculty of Health and Sports Science, Juntendo University, Inzai 270-1695, Chiba, Japan.
² Institute of Health and Sports Science & Medicine, Juntendo University, Inzai 270-1695, Chiba, Japan.
³ School of Sport and Health Science, Tokai Gakuen University, Miyoshi 470-0207, Aichi, Japan.
⁴ School of Medicine, Tokai University, Isehara 259-1193, Kanagawa, Japan.
⁵ School of Science and Technology for Future Life, Tokyo Denki University, Adachi, Tokyo 120-8551, Japan.
⁶ School of Public Health, Fudan University, Shanghai 200433, China.

Abstract

Purpose: Physical activity (PA) is widely recognized as a key factor in promoting skeletal muscle growth, though little is known about the specific impact of PA on the skeletal muscle development of preschool children. The purpose of this study is to investigate whether there is a relationship between PA levels and skeletal muscle thickness in preschoolers. By exploring this relationship, we hope to gain a better understanding of how PA can be used to promote healthy skeletal muscle development in preschoolers.

Methods: In this study, a total of 275 healthy Japanese preschoolers, aged 4-6 years, from seven nursery schools in the town of Togo were recruited. Participants were asked to wear an accelerometer for four consecutive days to record their daily steps and the amount of time spent in moderate-to-vigorous PA and t total physical activity. Muscle thickness (MTs) was measured using B-mode ultrasonography at four sites: the anterior and posterior thigh (AT and PT, respectively) and the anterior and posterior lower leg (AL and PL, respectively).

Results: On weekdays, boys were found to be more physically active and engaged in significantly higher levels of total physical activity and moderate-to-vigorous PA than girls. Both boys and girls recorded more physical activity, daily steps, and higher levels of total physical activity and MVPA on weekdays compared to weekends. After adjusting for daylight duration, multivariable regression analyses revealed that increased total physical activity and moderate-to-vigorous PA were positively associated with greater muscle thickness size in the anterior tibialis (AT) and posterior lower leg (PL) muscles (β = 1.11 and β = 1.37 for AT, β = 1.18 and β = 0.94 for PL, p < 0.05) in Japanese preschoolers.

Conclusions: The time spent involved in most of the different categories of moderate-to-vigorous PA was significantly higher for boys than for girls on the weekdays and weekends. Additionally, there was a positive correlation between time spent in moderate-to-vigorous PA and greater development of skeletal muscle in the lower body.

Keywords: accelerometer; development; growth; muscle thickness.

Abstract

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