Jumping Mechanography: Reference Centiles in Childhood and Introduction of the Nerve-Muscle Index to Quantify Motor Efficiency

Kyriakos Martakis; Ute Alexy; Christina Stark; Andreas Hahn; Rainer Rawer; Ibrahim Duran; Eckhard Schönau

doi:10.3390/jcm12185984

Jumping Mechanography: Reference Centiles in Childhood and Introduction of the Nerve-Muscle Index to Quantify Motor Efficiency

J Clin Med. 2023 Sep 15;12(18):5984. doi: 10.3390/jcm12185984.

Authors

Kyriakos Martakis^{1

2}, Ute Alexy³, Christina Stark⁴, Andreas Hahn², Rainer Rawer⁵, Ibrahim Duran^{1

6}, Eckhard Schönau^{1

6}

Affiliations

¹ Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
² Department of Pediatric Neurology, Justus-Liebig-University Giessen, Feulgen Str. 10-12, 35392 Giessen, Germany.
³ Department of Nutritional Epidemiology, Institute of Nutritional and Food Science, University of Bonn, 53115 Bonn, Germany.
⁴ Department of Neurology, Faculty of Medicine and University Hospital Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
⁵ Novotec Medical GmbH, 75172 Pforzheim, Germany.
⁶ Center of Prevention and Rehabilitation, UniReha, Faculty of Medicine and University Hospital Cologne, Lindenburger Allee 44, 50931 Cologne, Germany.

Abstract

Jumping mechanography provides robust motor function indicators among children. The study aim was to develop centiles for the single 2-leg jump (S2LJ) in German children and adolescents and to identify differences in children with obesity. Data were collected in 2004-2021 through the German DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study. All participants (6-18 years, mean age 11.4) performed annually an S2LJ aiming for maximum height on a Ground Reaction Force Platform. LMS (lambda-mu-sigma), including resampling, was used to develop centiles for velocity (v_max), jump height (h_max), relative force (F_max/BW), relative power (P_max/mass), impulse asymmetry and a new parameter to describe jump efficiency, the Nerve-Muscle Index (NMI), defined as v_max/(F_max/BW). Data from 882 children and adolescents were analyzed (3062 measurements, median 3 per individual). In females, F_max/BW values were higher in younger age but remained constant in adolescence. v_max, h_max and P_max/mass increased in childhood, reaching a plateau in adolescence. In males, v_max, h_max and P_max/mass showed a constant increase and the F_max/BW remained lower. Children with obesity showed lower F_max/BW, h_max, v_max and the NMI, hence, lower velocity per relative force unit and less efficient jump. The centiles should be used to monitor motor development in childhood. The NMI is a surrogate for motor efficiency.

Keywords: DONALD study; Nerve–Muscle Index (NMI); force; jumping mechanography; motor efficiency; obesity; power; single-two-legged jump; velocity.

Grants and funding

The DONALD study is funded by the state of Northrhein Westfalia.