MIRA University of Twente
Department of Biomechanical Engineering

Department of Biomechanical Engineering

Balroom - Effect of soft support surfaces on balance


Twente University (also open for students from TU Delft)


(Bio-)Mechanical engineering, Electrical engineering, Biomedical engineering or similar




Denise Engelhart (Twente, daily supervisor)

Alfred Schouten



Postural instability and falls are common and devastating features of ageing and many neurological, visual, vestibular or orthopedic disorders. Current management of these problems is hampered by the subjective and variable nature of the available clinical balance measures.

Steadiness during standing and walking on soft support surfaces decreases with age and is a potential risk factor for unexpected falls in elderly subjects. Therefore older adults undergo functional balance training that is specifically oriented to improve steadiness of Centre Of Pressure (CoP) while standing on compliant surface (CS). Nevertheless, looking only at CoP and Centre of Mass (CoM) sway does not really tell us if proper compensation strategies are used. It is expected that as only ankle torque is not sufficient to compensate for the imbalance, hip strategy should be used.

Assignment introduction

The Bilateral Ankle Perturbator (BAP) is developed to perturb the human balance and to investigate the underlying mechanisms of balance control. It consists of two small foot-size platforms driven by an electromotor, which can rotate around the ankle axis. Hereby the proprioceptive information coming from the muscles is disturbed and the human balance is challenged. The actuation of the BAP so far is only used in position mode, but there are possibilities to extend the application, using force mode.

Force perturbations create the possibility to manipulate the stiffness of the support surface, similar to having participants stand on foam. Using an actuated apparatus has the advantage of being able to manipulate the stiffness in a very controlled fashion and as such to investigate adaptation of human balance control to stiffness of the support surface.


The aim is to optimally control the BAP in force mode and investigate the use of ankle and hip strategy and sensory reweighting in healthy subjects.


o Literature review on balance control in older adults and functional training on compliant surfaces

o Extend the usability of the BAP with force control

o Investigate balance compensation methods, like ankle and hip strategy on compliant surfaces using system identification techniques

o Investigate sensory reweighting on compliant surfaces using system identification techniques

o Write a report in the form of a scientific paper

Further information

If you are interested in this assignment, please contact Alfred Schouten (a.c.schouten@tudelft.nl) or Denise Engelhart (d.engelhart@utwente.nl) for further information.