From lab to life: LJMU exploring new possibilities for human movement analysis

Understanding how people move can help clinicians assess walking difficulties and coaches examine sporting technique. But measuring movement in detail often means bringing people into a specialist laboratory and placing markers on their bodies. For some patients and sporting activities, this can be challenging. 

At Liverpool John Moores University (LJMU), researchers are exploring how markerless motion capture technology can extend movement analysis into clinical, community and sporting settings, without body-mounted markers or sensors. 

Led by Dr Rich Foster, Associate Professor in Biomechanics, the LJMU team is working with Theia Markerless Inc., (Kingston, Ontario, Canada) and partners including Alder Hey Children’s Hospital and GB Taekwondo to make assessment more accessible and study movements that are difficult to capture using conventional methods. 

Taking movement analysis beyond the laboratory 

Many people will recognise motion capture from behind-the-scenes footage of films such as The Lord of the Rings and Avatar, where specialist cameras track reflective markers on actors’ suits. The same principle is used in biomechanics: in film, the movement data help bring digital characters to life; in research and clinical assessment, they help us understand how joints and body segments move. 

For the past 30 years, marker-based motion capture has played a central role in movement research and continues to be the established clinical reference standard for three-dimensional gait analysis. The precision, repeatability and controlled conditions offered by laboratory testing are major strengths. However, marker application takes time, requires access to specific body landmarks and can involve changes to clothing. Markers must also remain in place and visible throughout the assessment. These requirements can make it difficult to study some people and activities, particularly where movements involve physical contact, protective equipment or close interaction. 

Markerless systems such as Theia3D use synchronised video cameras and artificial intelligence to estimate body movement without markers. Researchers can then calculate joint angles and examine how people move. LJMU’s team takes these camera systems to different locations, creating opportunities to collect movement data in settings relevant to healthcare, everyday activity and sporting performance. 

Making assessment more accessible 

For a child with cerebral palsy, understanding how they walk can help clinicians plan treatment and assess its effects. However, the preparation needed for traditional movement analysis can be challenging. Some children find marker application and changes of clothing distressing, particularly those with sensory difficulties. For children who fatigue quickly, preparation can also reduce the energy available for the assessment itself. 

Working with Dr Henrike Greaves and colleagues at Alder Hey Children’s Hospital, LJMU researchers are investigating how markerless measurements compare with established marker-based assessments of children’s walking, including children with cerebral palsy. Removing the need to apply markers could make assessment more tolerable and allow more of an appointment to focus on movement rather than preparation. The collaboration aims to establish where markerless technology can provide useful clinical information, particularly for children who find conventional assessment difficult to complete. 

Capturing athletes moving together 

In sport, performance depends on responding to other people. A footballer changes direction as an opponent approaches. A taekwondo athlete adjusts their position and technique throughout an exchange. Studying an athlete alone captures only part of that picture. LJMU’s recent pilot work with GB Taekwondo explores how markerless technology can capture two athletes during sparring and other training activities. By removing the need for markers that could fall off during contact, the approach offers opportunities to examine complex movements alongside the interaction between opponents. 

The team’s football work explores similar possibilities, with the potential to track both players and the ball. Capturing these movements together could help researchers understand how players respond to one another and to the ball, an interaction that has traditionally been difficult to quantify. These applications could help researchers and coaches bring biomechanical analysis closer to the demands of training and performance.

Establishing where the technology works best 

Alongside these opportunities, LJMU’s research examines the accuracy and repeatability of markerless measurements across different movements and environments. Camera positioning, lighting and visibility still matter. People can obscure one another during close interaction, and successfully tracking a movement does not mean every measurement is suitable for a clinical or coaching decision. 

Marker-based assessment remains essential, particularly where interpretation relies on established clinical methods. Through careful evaluation and collaboration with healthcare and sporting partners, LJMU’s researchers are establishing where markerless motion capture can add value, making assessment accessible to more children, taking measurement into different settings and helping us understand how people move together.