New research lights the way in pressure measurement

Friday, 26 July 2019

Researchers have developed a new way to accurately measure force and pressure during physical activities that has a number of potential applications, from improving athletic performance and footwear to the design of prosthetic limbs.

Scientists at the University of Nottingham have developed a system using light to measure the pressure exerted by shoes and feet during different activities. The research published in Scientific Reports shows that this system creates accurate spatial maps of the force and pressure distribution that have numerous potential applications in sports sciences and medicine.

The technique used is called Frustrated Total Internal Reflection (FTIR) and it uses measurements of the amount of light that is scattered in the regions of contact between a soft object and a hard transparent slab of material (often acrylic or glass).

Under pressure

Using the FTIR technique the team built a dual imaging system by wrapping strips of ultra-bright red LED’s around the outside edges of two slabs of acrylic polymer which they built into a platform with a camera underneath. When pressure is applied to the slabs, light is scattered by the contacting object and a camera records images which can be used to create accurate spatial maps showing exactly where pressure is exerted

Although there is equipment available that measures some aspects of pressure, this system is the first to use light in this way to create millimetre accurate maps of pressure and force with millisecond resolution. We can create a clear picture of exactly which parts of the foot or shoe are exerting more or less pressure, something that could be applied in a number of useful ways across sports and medicine.
Dr James Sharp, School of Physics and Astronomy

Athletes could be measured during routine training activities to ensure that they distribute their weight uniformly and develop physical strength in both legs evenly. Similar measurements are also helpful for the design and optimisation of sports shoes, where the size, placement and orientation of structures on a shoe outsole can be used to improve characteristics such as impact resistance and frictional interactions.

Medical applications

Medical applications include measuring the pressure distributions beneath the feet of patients with spina bifida and diabetic patients. With diabetes patients, these measurements are used to locate and facilitate treatment of painful ulcers whose early detection can prevent the need for whole foot  amputation.

Pressure measurements are also valuable in monitoring progress during the rehabilitation of athletes or elderly patients who have recently suffered a fall and in the design of orthotic and prosthetic devices.

Dr Sharp continues: “Conventional pressure mats are typically based upon an array of electrically addressable elements comprising resistive, capacitive or piezoelectric sensors that are sensitive to the local pressure that is exerted upon them. These devices tend to be quite expensive and inaccessible to many researchers and clinics. However, optical methods  of force detection offer an accurate and potentially low-cost alternative to electrically addressable pressure mats.”

Story credits

More information on the is available from Dr James Sharp at the University of Nottingham on or Jane Icke Relations Managers for the Faculty of Science at the University of Nottingham, on +44 (0)115 951 5751

Jane Icke - Media Relations Manager Science
Phone: 0115 951 5751

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Notes to editors: 

The University of Nottingham is a research-intensive university with a proud heritage, consistently ranked among the world's top 100. Studying at the University of Nottingham is a life-changing experience and we pride ourselves on unlocking the potential of our 44,000 students - Nottingham was named both Sports and International University of the Year in the  2019 Times and Sunday Times Good University Guide, was awarded gold in the TEF 2017 and features in the top 20 of all three major UK rankings. We have a pioneering spirit, expressed in the vision of our founder Sir Jesse Boot, which has seen us lead the way in establishing campuses in China and Malaysia - part of a globally connected network of education, research and industrial engagement. We are ranked eighth for research power in the UK according to REF 2014. We have six beacons of research excellence helping to transform lives and change the world; we are also a major employer, proud of our Athena SWAN silver award, and a key industry partner- locally and globally.

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