Journal Articles

Examination of muscle morphology and neuromuscular function in normal weight and overfat children aged 7 to 10 years

July 12, 2018

Trent J. Herda, Eric D. Ryan, Martin Kohlmeier, Michael A. Trevino, Gena R. Gerstner, Erica J. Roelofs.  Examination of muscle morphology and neuromuscular function in normal weight and overfat children aged 7 to 10 years. Scandinavian Journal of Medicine & Science in Sports. https://doi.org/10.1111/sms.13256 First published: 30 June 2018

Author Affiliations

Neuromechanics Laboratory, University of KansasLawrence, KS

Neuromuscular Research Laboratory, Department of Exercise Science and Sport Science, University of North Carolina at Chapel HillChapel Hill, NC and Human Movement Science Curriculum, University of North Carolina at Chapel HillChapel Hill, NC

Department of Nutrition, School of Medicine, University of North Carolina at Chapel HillChapel Hill, NC and Nutrigenetics Laboratory, University of North Carolina at Chapel HillKannapolis, NC

Neuromechanics Laboratory, University of KansasLawrence, KS

Neuromuscular Research Laboratory, Department of Exercise Science and Sport Science, University of North Carolina at Chapel HillChapel Hill, NC and Human Movement Science Curriculum, University of North Carolina at Chapel HillChapel Hill, NC

Department of Nutrition, Health and Human Performance, Meredith College, Raleigh, NC

Abstract

Neuromuscular function in young overweight/obese (OF) children is not well described.

Aim

This study examined isometric and isokinetic leg extensor strength, muscle size (mCSA) and tissue composition as measured via echo intensity (mEI), and motor unit (MU) firing rates in normal weight (NW) and OF children aged 7 to 10 years.

Methods

Fourteen NW (8 girls and 6 boys, BMI:15.8±1.4 kg/m2) and 15 OF (10 girls and 5 boys, BMI:20.8±2.3 kg/m2) children volunteered to perform this study. Percent body fat (%BF) was measured and mCSA, mEI, and subcutaneous fat (sFAT) of the vastus lateralis (VL) was assessed. MU mean firing rates (MFRs) in relation to recruitment threshold (RT) of the VL were assessed during submaximal isometric contractions. Maximal isokinetic contractions were performed at 1.05 rad·s−1 and 4.20 rad·s−1. The 95% confidence intervals (CI) from the statistical tests are presented.

Results

The OF children had greater %BF (95% CI=‐15.1 to ‐7.2), mCSA (95% CI=‐4.1 to 1.2), mEI (95% CI=‐22.3 to ‐5.9), and sFAT (95% CI=‐0.5 to ‐0.1), greater rate of strength loss with increasing isokinetic velocities (95% CI=0.4 to 5.4) and, smaller range in MFRs (95% CI=0.007 to 7.136) at the steady torque than the NW children.

Conclusions

The OF children had poorer muscle tissue composition, greater velocity‐related impairments in muscle strength, and a smaller range of MFRs at the targeted torque that may suggest altered MU recruitment strategies. Interventions in OF children should include exercises and recruit higher‐threshold MUs, such as, high‐intensity resistance exercises.

This article is protected by copyright. All rights reserved.

Comments are closed.

Connect With Us