Funding for this research was provided by:
Received: 7 June 2020
Accepted: 11 December 2020
First Online: 7 January 2021
Ethics approval and consent to participate
: We obtained ethical approval from the Institutional Ethics Committee of the UKA, Aachen, Germany (EK 327/16) for the baby measurement and informed consent from the parents. The adult measurement is a self-experiment.
: We obtained informed consent from the parents for publication.
: The authors declare that they have no competing interests.