T.P.47: A new index of muscle development for healthy children using bioelectrical impedance analysis

• Published in: Neuromuscular disorders : NMD Vol. 24; no. 9-10; p. 908
• Main Authors: Uchiyama, T., Nakayama, T., Hattori, A., Kuru, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2014
• ISSN: 0960-8966; 1873-2364
• DOI: 10.1016/j.nmd.2014.06.378

In children, muscle volume and diameter of the muscle fibre generally increases, and the interstitial tissues among muscle decrease with their growth. We report a new method to analyse muscle development using bioelectrical impedance analysis (BIA). Ninety-two children aged 0 to 16 were enrolled to our study, with the consent from their parents. An impedance analyzer (BCA-100_CTanita Corp., Japan) and 10mm wide stainless steel electrodes were used. The current used in the measurement was lower than 100μA, and the 9 frequencies between 5 and 250kHz. The impedance was measured at the middle part of the thigh, lower leg and upper arm. We measured the impedance index at 50kHz (ZI50), which is generally used for estimating muscle volume in body composition analysis. We evaluated the ratio of ZI50 to the length between the electrodes, which we called as net muscle volume by BIA (nMV_BIA), and our new index: muscle density index (MDI). The MDI is calculated by the subtraction of the division ration of the impedance at 5kHz (Z5) by that at 250kHz (Z250) from 1 (1 – Z5/Z250), that was considered to reflect the ratio of intracellular volume to whole muscle bundle of extremities. The results from nMV_BIA and MDI were analysed among the ages using Spearman rank-correlation analysis. The nMV_BIA of thighs, lower legs, and upper arm were measured as 0.449, 0.191, and 0.127cm/Ω, respectively. The MDI of thighs, lower legs, and upper arm were measured as 0.279, 0.290, and 0.202, respectively. These results significantly increased with the ages of the subjects (p<0.001). We can evaluate the development of the muscle of healthy volunteers using BIA. We showed the increase of nMV_BIA and MDI with ages, and it suggests that we will be able to evaluate muscle volume and muscle development simultaneously using BIA. BIA is able to be used for humans easily, noninvasively, and repeatedly.