Height-Specific Reference Centiles for Jumping Mechanography in Children: Retrospective Analysis of the DONALD Study Cohort.

OBJECTIVES: Jumping mechanography is a common method to analyze muscle function. To date, mainly age- or weight-specific pediatric reference centiles for jumping mechanography have been published. The use of age-related references in children with small stature (defined as height below the age-specific third centile) might lead to misinterpretation of actual jumping performance. Thus, the study aim was the development of height-specific mechanography reference centiles of healthy children and show application in children with small stature. METHODS: Data from 882 children (aged 6-18 years; height 100-200cm) from the DONALD cohort was analyzed using the LMS (lambda-mu-sigma)-method. Sex-specific centiles were calculated for maximal velocity (Vmax), Nerve-Muscle Index (NMI), maximal power (Pmax) and maximal force (Fmax), both related to body mass. Age- and height-specific jumping parameters were individually compared in healthy children with small stature. RESULTS: Vmax, Pmax and NMI increased with higher stature until a plateau was reached. Fmax stayed rather stable over time. Age-specific z-scores of Vmax, Pmax and NMI in children with small stature were lower than the height-specific z-scores. CONCLUSIONS: In this article first height- and sex-specific reference centiles for jumping mechanography in healthy German children are presented. This study highlights the beneficial application of height-specific reference centiles for interpretation of jumping performance in children with small stature.