Nobody is average

​Dr. Johan Molenbroek is the only researcher in the Netherlands paid by taxpayers to measure their bodies and make the data available to designers.

Molenbroek, an associate professor of applied ergonomics in the faculty of Industrial Design Engineering (IO), originally trained as a biomedical engineer to design prosthetics. He began by adapting human dimensions available from German DIN norms and compiling information himself using height and weight data from growth studies done around every 15 years in the Netherlands. His resulting first DINED table of body dimensions in 1980 was used as the basis for Dutch norms until 2000. This was the forerunner of the DINED online database, which won a Dutch Data Prize in 2014.

He applies knowledge derived from the dimensional data to provide guidelines for the interaction between humans and artefacts in specific contexts such as schools, WCs and cars. Molenbroek proposed a methodology for optimising product design based on the function of product groups, user groups and relevant physical aspects. Since nobody is average, single mean dimensions say little and few products can be designed for the mean. The designer should consider the distribution, spread and percentiles of various body measurements and minimise user exclusion.

His understanding of trends in body dimension data allows Molenbroek to make predictions and aid designers. “Since 2010 the Dutch have stopped growing in height after a spurt between 1965 and 1980. But their body mass index is increasing, indicating that they are now growing horizontally,” he said. “Chilean data shows their children are getting taller due to dietary shifts to more high energy foods.”

“Aircraft manufacturers approached me for trends in data on hip widths to help them choose the appropriate dimensioning of future plane seats,” said Molenbroek. He has helped school furniture producers interpret children’s body dimensions to identify lower leg lengths, not body heights, as a key indicator for effective furniture design.

Molenbroek also worked with Canadian helmet designer, Roger Ball, who realised that his helmets fitted poorly on Chinese heads. “Measurement of 2,000 Chinese heads revealed that they are rounder than westerners’ and allowed an effective redesign of his products,” he said.

Privacy & facial data
3D laser scanners have boosted anthropometry, but bring their own challenges. For example, privacy can be an issue with facial data. “We used photogrammetric cameras to make 3D images of the faces of 300 children to optimise a mask for children with

breathing problems,” he said. “To hide their identities the parametric data was manipulated to change the faces slightly without compromising information on shape and size.” In addition, the capture of ears and hands remains difficult. Until recently scanners could not get behind ears, so for earphone design casts of subjects’ ears w ere still made. And subjects cannot keep their hands still enough for normal 3D scanners. A new scanner prototype developed at IO solves this by using a hoop surrounding the hand, mounting multiple scanners working at high speed.

About steep Dutch stairs, Molenbroek said, “They are not ideal. The whole foot should fit on the tread and the riser distance should be short. This is an accident risk factor for the elderly at home, wearing slippers due to swollen feet and sometimes with poor vision and trouble keeping balance.”

Editor Redactie

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