Accuracy of Kinovea Software in Estimating Body Segment Movements During Falls Captured on Standard Video: Effects of Fall Direction, Camera Perspective and Video Calibration Technique

Falls are a major cause of unintentional injuries. Understanding the movements of the body during falls is important to the design of fall prevention and management strategies, including exercise programs, mobility aids, fall detectors, protective gear, and safer environments. Video footage of real-life falls is increasingly available, and may be used with digitization software to extract kinematic features of falls. We examined the validity of this approach by conducting laboratory falling experiments, and comparing linear and angular positions and velocities measured from 3D motion capture to estimates from Kinovea 2D digitization software based on standard surveillance video (30 Hz, 640x480 pixels). We also examined how Kinovea accuracy depended on fall direction, camera angle, filtering cut-off frequency, and calibration technique. For a camera oriented perpendicular to the plane of the fall (90 degrees), Kinovea position data filtered at 10 Hz, and video calibration using a 2D grid, mean root mean square errors were 0.050 m or 9% of the signal amplitude and 0.22 m/s (7%) for vertical position and velocity, and 0.035 m (6%) and 0.16 m/s (7%) for horizontal position and velocity. Errors in angular measures averaged over 2-fold higher in sideways than forward or backward falls, due to out-of-plane movement of the knees and elbows. Errors in horizontal velocity were 2.5-fold higher for a 30 than 90 degree camera angle, and 1.6-fold higher for calibration using participants’ height (1D) instead of a 2D grid. When compared to 10 Hz, filtering at 3 Hz caused velocity errors to increase 1.4-fold. Our results demonstrate that Kinovea can be applied to 30 Hz video to measure linear positions and velocities to within 9% accuracy. Lower accuracy was observed for angular kinematics of the upper and lower limb in sideways falls, and for horizontal measures from 30 degree cameras or 1D height-based calibration

How fine are the emperor’s clothes? – motivating critical and ethical design practices by deconstructing engineering codes and standards

At the University of Toronto, Engineering Science students are typically introduced to the engineering codes and standards that they are expected to incorporate into framing and responding to engineering design challenges in their first year of study. In our experience, however, students do not always appreciate that these codes and standards may not reflect the interests of key (and potentially under-represented) stakeholders, and thus may not be appropriate for their engineering context. To encourage our students to adopt a more critical perspective when working with codes and standards, we exposed them to case examples of contentious regulations, and highlighted the objectives, people, and processes behind the development of these works. Our examples focus on common products to which first-year students can relate, such as handrails and stairs. By exposing our students to the people and processes by which codes and standards are developed, and to the controversies associated with contentious policy decisions, we expect that students will adopt a rigorous approach to using engineering codes and standards in their design activities.The authors gratefully acknowledge funding from the Canadian Institutes of Health Research Operating Grants (CIHR MOP 142178)(VK), the AGE-WELL Network of Centres of Excellence in Technology and Aging Graduate Student Scholarships (VK), and Toronto Rehabilitation Institute Graduate Student Scholarships (VK).VK also gratefully acknowledges funding from the Institute of Biomaterials and Biomedical Engineering at the University of Toronto to present at CEEA 2017

Using Role-Playing Simulations to Teach Quality Control in the Design of Medical Devices

A simulation is used to facilitate cooperative and team-based learning to introduce concepts of human factors, risk analysis, and quality control applied to the design of medical devices. We further use a friendly game-based approach to simulate the dynamics between a customer, a regulatory agency, and competitive manufacturers. Students are divided into manufacturing teams/companies and teaching assistants act as the customer and regulator. To promote positive interdependence and individual accountability, each student within a company is assigned roles of CEO, inspector, marketer, and designer. The goal for each company is to design and produce as many eye patch medical devices as possible, which must be approved by the regulator, within a tight deadline. Products are evaluated by the customer, who decides what price to pay for each unit, at the end of production. The most successful company is determined by the greatest amount of money earned after two rounds of production and sales.The authors gratefully acknowledge financial support from the Canadian Institutes of Health Research Operating Grants (CIHR MOP 142178) (VK), the AGE-WELL Network of Centres of Excellence in Technology and Aging Graduate Student Scholarships (VK), and Toronto Rehabilitation Institute Graduate Student Scholarships (VK). VK also gratefully acknowledges funding from the University of Toronto’s Institute of Biomaterials and Biomedical Engineering to present at CEEA 2017

Using a Multidisciplinary Team-Based Challenge to Promote Brainstorming and Prototyping of Medical Devices

Multidisciplinary teams of engineering and life science students are challenged to remove a foreign object from a child’s ear canal. Each group is provided with a model ear canal and asked to remove objects of different shapes and materials. The experience of iterative problem solving serves to encourage brainstorming and practice the prototyping process, which each team should complete in their over-arching design projects to be successful. Surveys taken from the students before and after the prototype challenge showed they learned more about the brainstorming method they used, but also learned what worked well for other groups. Student feedback indicates that this activity prepared them to be creative and tackle the larger challenge of developing a solution to their own design project as part of the Biomedical Engineering Capstone Design course.The authors gratefully acknowledge financial support from the Canadian Institutes of Health Research Operating Grants (CIHR MOP 142178) (VK), the AGE-WELL Network of Centres of Excellence in Technology and Aging Graduate Student Scholarships (VK), and Toronto Rehabilitation Institute Graduate Student Scholarships (VK). VK also gratefully acknowledges funding from the University of Toronto’s Institute of Biomaterials and Biomedical Engineering to present at CEEA 2017

Individual, task, and environmental influences on balance recovery: a narrative review of the literature and implications for preventing occupational falls

Balance recovery is a complex, multi-factorial task. When examining occupational environments for fall safety hazards, practitioners must be aware of how a worker’s ability to recover from balance loss and avoid a fall depends on their unique individual characteristics, the task they are performing, and their work environment. Balance recovery can be negatively affected by factors related to the individual (e.g., aging, obesity, arthritis, low back pain, fatigue, and peripheral neuropathies); the task (e.g., holding objects or performing multiple tasks); and the environment (e.g., slopes or stairs). Conversely, balance recovery can be enhanced by exposure to balance disturbances in the context of perturbation training, and by environmental design (e.g., appropriately-designed handrails). By understanding how individual, task, and environmental factors influence balance recovery and overall fall risk, occupational health and safety practitioners will be in a stronger position to design and implement safety controls to prevent occupational slips, trips, and falls

Quantifying segmental contributions to center-of-mass motion during dynamic continuous support surface perturbations using simplified estimation models

Investigating balance reactions following continuous, multidirectional, support surface perturbations is essential for improving our understanding of balance control in moving environments. Segmental motions are often incorporated into rapid balance reactions following external perturbations to balance, although the effects of these motions during complex, continuous perturbations have not been assessed. This study aimed to quantify the contributions of body segments (ie, trunk, head, upper extremity, and lower extremity) to the control of center-of-mass (COM) movement during continuous, multidirectional, support surface perturbations. Three-dimensional, whole-body kinematics were captured while 10 participants experienced 5 minutes of perturbations. Anteroposterior, mediolateral, and vertical COM position and velocity were calculated using a full-body model and 7 models with reduced numbers of segments, which were compared with the full-body model. With removal of body segments, errors relative to the full-body model increased, while relationship strength decreased. The inclusion of body segments appeared to affect COM measures, particularly COM velocity. Findings suggest that the body segments may provide a means of improving the control of COM motion, primarily its velocity, during continuous, multidirectional perturbations, and constitute a step toward improving our understanding of how the limbs contribute to balance control in moving environments

Teaching credible validation and verification methods to a large, multidisciplinary first-year engineering design class

This paper describes our experiences in teaching credible validation and verification methods to a class of 250 first-year Engineering Science students at the University of Toronto. While our students have previously developed proof-of-concept prototypes, this was the first year that testing their prototypes against key design requirements – and substantially integrating stakeholder feedback into their projects – were course expectations. Core strategies to support our students included leveraging the expertise of a multidisciplinary teaching team; training students to collect and interpret data from community stakeholders; demystifying prototyping and testing through small-scale activities; and legitimizing our expectations through real-world examples. Student design teams generally performed well with respect to validation and verification criteria on their summative project evaluations. Most teams effectively integrated stakeholder feedback with other research into developing and refining their designs, and demonstrated that their prototypes addressed key metrics. Challenges to be addressed in future course iterations are discussed.The authors acknowledge funding from the Canadian Institutes of Health Research Operating Grants (CIHR MOP 142178) (VK), the AGE-WELL Network of Centres of Excellence in Technology & Aging Graduate Student Scholarships (VK),Toronto Rehabilitation Institute Graduate Student Scholarships (VK), the Ontario Ministry for Research & Innovation (NW), the Natural Sciences & Engineering Research Council of Canada (NW, AF), the Training in Organ-on-a-Chip Engineering Program Scholarships (NW), and the Weber & Mariano Graduate Scholarships (NW). We also gratefully acknowledge funding from U of T’s Institute of Biomaterials & Biomedical Engineering (VK) and Division of Engineering Science (NW) to present at CEEA 2017

Age-related differences in dynamic balance control during stair descent and effect of varying step geometry

The incidence of stairway falls and related injuries remains persistently high; however, the risk of stair injuries could be reduced through improved stairway design. The current study investigated dynamic balance control during stair descent and the effects of varying the step geometry. Data were collected from 20 healthy young and 20 older adults as they descended three staircases (riser heights of 7, 7.5 and 8 inches (178, 190 and 203 mm, respectively)). At each riser height, the tread run length was varied between 8 and 14 inches (203 mm and 356 mm) in one-inch (25 mm) increments. Kinematic data provided measures of segmental and whole-body dynamic control. Results demonstrated that older adults had greater lateral tilt of the upper body than young adults, but actually had larger margins of stability than the young in the antero-posterior direction as a result of their slower cadence. Nonetheless, for both age groups, the longer run lengths were found to provide the largest margins of stability. In addition, increase in run length and decrease in riser height tended to reduce forward upper body tilt. These results help to explain the underlying biomechanical factors associated with increased risk of falls and the relationship with step geometry. Considering the importance of stair ambulation in maintaining independence and activity in the community, this study highlights the definite need for safer stair design standards to minimize the risk of falls and increase stair safety across the lifespan.This work was sponsored by the Canadian Institutes of Health Research, the National Institute on Disability and Rehabilitation Research, and an Ontario Graduate Scholarship

The Effect of Wave Motion Intensities on Performance in a Simulated Search and Rescue Task and the Concurrent Demands of Maintaining Balance

Objective The purpose of this study was to examine how intensity of wave motions affects the performance of a simulated maritime search and rescue (SAR) task. Background Maritime SAR is a critical maritime occupation; however, the effect of wave motion intensity on worker performance is unknown. Methods Twenty-four participants (12 male, 12 female) performed a simulated search and rescue task on a six-degree-of-freedom motion platform in two conditions that differed in motion intensity (low and high). Task performance, electromyography (EMG), and number of compensatory steps taken by the individual were examined. Results As magnitude of simulated motion increased, performance in the SAR task decreased, and was accompanied by increases in lower limb muscle activation and number of steps taken. Conclusions Performance of an SAR task and balance control may be impeded by high-magnitude vessel motions. Application This research has the potential to be used by maritime engineers, occupational health and safety professionals, and ergonomists to improve worker safety and performance for SAR operators

The Effect of Wave Motion Intensities on Performance in a Simulated Search and Rescue Task and the Concurrent Demands of Maintaining Balance

Objective: The purpose of this study was to examine how intensity of wave motions affects the performance of a simulated maritime search and rescue (SAR) task. Background: Maritime SAR is a critical maritime occupation; however, the effect of wave motion intensity on worker performance is unknown. Methods: Twenty-four participants (12 male, 12 female) performed a simulated search and rescue task on a six-degree-of-freedom motion platform in two conditions that differed in motion intensity (low and high). Task performance, electromyography (EMG), and number of compensatory steps taken by the individual were examined. Results: As magnitude of simulated motion increased, performance in the SAR task decreased, and was accompanied by increases in lower limb muscle activation and number of steps taken. Conclusions: Performance of an SAR task and balance control may be impeded by high-magnitude vessel motions. Application: This research has the potential to be used by maritime engineers, occupational health and safety professionals, and ergonomists to improve worker safety and performance for SAR operators