Rehabilitation Robotics

Biomechanics and Disability

 

Wheelchair biomechanics involves understanding the most efficient ways in which manual wheelchair users (MWUs) can propel themselves. However, there exists a knowledge void that spawns from the inability to study forces, angles and muscles simultaneously due to technical limitations. And the knowledge we do have is not readily translated into exercise guidelines for MWUs. We intend to fill these gaps by using an immersive, virtual world where the participant can go through similar real-world movements within the stationary confines of a VR cube. Here, we can carry out recordings that would be otherwise difficult in the real-world, including motion capture, electromyography and metabolic analysis.

Wheelchair Biomechanics

Globally, an estimated sixty-five million people require daily use of a wheelchair. Many will use a manual wheelchair in their day-to-day life and rely on their arm strength to get around. However, the human shoulder is not suited to the repetitive and strenuous forces required to propel a manual wheelchair. As a result, upper limb pain and pathology arises quickly after confinement to a manual wheelchair.
 
Our hope for this research area is to develop and suggest practices that could protect the shoulder and prevent shoulder complaints in manual wheelchair users. This simple idea has inspired many research studies in our lab and has the potential to revolutionize the way we research and understand manual wheelchair propulsion. The goal in studying wheelchair biomechanics is to help individuals in manual wheelchairs meet their functional goals. This research area examines wheelchair propulsion through biomechanical monitoring of a specific propulsion task using an immersive VR ergometer system, developed in the lab.
 
Our research focuses on two areas:
 
Straight Line Propulsion & Parasports:
Parasports not only allow active individuals to remain active after injury, but also give these individuals opportunities to retain the social benefits of competitive sport. Additionally, there is mounting interest worldwide in health and wellness by all citizens to improve their quality and quantity of life via better nutrition, exercise and recreation. Manual wheelchair users partake in this health and wellness movement partly via competitive wheelchair sport. Wheelchair racing athletes are at an even greater risk of overuse injuries in their upper extremities, as compared to everyday manual wheelchair users, due to the extreme forces they employ and intense speeds they travel at. The purpose of this research is to enable manual wheelchair athletes to meet their goals while minimizing the risk of injuries. Learning what is the most efficient straight-line propulsion style for function and protection of the shoulder in wheelchair athletes will inform our understanding of efficiency in everyday manual wheelchair users.
 
Curvilinear Propulsion & Maneuverability: 
Historically, we have limited our scope in wheelchair biomechanical studies to straight line propulsion studies. This upcoming year, we plan to take a new turn by characterizing wheelchair maneuverability through the development of intelligent technology, biomechanical models, and laboratory simulation. Maneuverability is crucial because both straight line and curvilinear paths poorly represent the way everyday wheelchair users actually move. Metadata on full-time wheelchair users show that they move in short bouts, 85 per cent of which is less than a minute, about 90 times daily. We have demonstrated that we can use VR to develop biomechanical models for straight-line wheelchair propulsion using The MotionMonitor software. The next step is to create a comprehensive model that accounts for non-straight-line propulsion. In doing so, we hope to better understand wheelchair maneuverability.

Functional Bariatric Assessment

Biomechanics and disability is not just restricted to studies involving a wheelchair, however. Using our motion capture space, we have demonstrated that we can study ambulation for very distinct populations such as individuals with obesity. We explored the impact of a bariatric simulation suit on functional mobility in adults without obesity. Specifically, we captured the functional movements information of individuals without obesity, participants wearing the bariatric simulation suit and individuals without obesity using the 3D motion capture system.

Technology

  • EON iCube
    The iCube is an immersive VR space that strives to simulate the real world in a more confined and controlled environment. The system is ideal for visualization, modelling, and motion simulation. The Cube is equipped with Optitrack motion capture cameras, which can collect quantifiable movement data from the subject inside. Additionally, Vicon motion capture cameras add to the immersive power of the Cube by incorporating head tracking capabilities, allowing for a more authentic VR experience. We are utilizing the Cube to explore wheelchair biometrics by coupling it with a wheelchair ergometer. This combination allows us to collect metrics that can be used in conjunction with VR to study and sequence wheelchair propulsion, enabling the gathering of quantifiable data which can help to develop improved propulsion techniques.
  • Motion Capture Space
    Motion capture records the 3D movement of objects and can be used to detect movement of objects over time. Traditional motion capture analysis in research looks at the changes in joint angle over time. The twenty-four motion capture cameras in the lab cover an area of about 2 X 4 metres and can be used to measure gait or propulsion style.
  • Redliner
    Redliner is a lightweight, non-contacting, battery-powered activity monitor that can be attached to the spokes of a manual wheelchair user’s wheels. Velocity, acceleration, distance traveled, applied force, and resistive force are collected using Redliner.
  • Track Compensator Indicator
    This device will digitally represent the activation and deactivation of a racing wheelchair’s steering mechanism. Standard racing wheelchairs today have three wheels and are steered using a track compensator device. The digital indicator our lab has created will tell a racing athlete when they have engaged their track compensator, which may help them steer more efficiently.
  • Wheelchair Ergometer
    The wheelchair ergometer consists of two rollers, which have inertial characteristics like those encountered when propelling a wheelchair on a flat smooth surface such as linoleum. Two current controlled magnetic brakes are used to adjust the rolling resistance of the ergometer in real-time. For a participant to turn the ergometer, the wheel furthest from the center of rotation is rotated at a greater speed than the opposing wheel, causing the chair to travel in an arc.