Saturday, April 4, 2015
Wednesday, March 11, 2015
Making biomechanical measurements in the field:
Use of Kinetisense to examine post-exercise proprioception
prepared by Dr. Jon Doan, University of Lethbridge, Alberta
Kinesthetic proprioception is the awareness of the position and movement of parts of the body (KP). KP is an important component in many human movements, from our first steps to our biggest physical achievements to our everyday activities, like maintaining balance. KP relies on communication between the peripheral nervous system and the central nervous system to interpret current position, then provide feedback on subsequent changes in position.
Unfortunately, accurate KP can be a challenge in some neuropathologies, including Parkinson disease. This deficit can lead to uncoordinated movements, postural disturbance, and increased risk of falls. Vigorous exercise has provided good therapy for balance and movement deficits amongst some neuropathological patients, but the specific neuromechanisms are unclear. Understanding the immediate and long-term benefits of exercise on KP and function would be extremely helpful for improved health and quality of life.
The Kinetisense system provides a quick and accurate means to immediately assess proprioception in the field. Conventional motion capture requires extensive calibration plus participant preparation to capture data. With the Kinetisense, a participant can step in front of the Kinect sensor in their street clothes and near-instantly start producing motion capture data. This is particularly important in field environments, like sports settings or workplaces, where long duration set-up might not be feasible, given time, space, or financial constraint.
In this case study, we used the Kinetisense system in the dressing room of a local arena to examine the immediate and long-term influence of ice skating exercise on proprioception for a person living with Parkinson disease, and for a neurotypical control subject. Both exercising subjects were tested before and after their sixty minute skating practice session, and both exercising subjects were regular skaters. Four control subjects were used for comparison – they were also tested pre- and post-, but skating exercise was replaced with television watching for the control group. None of the controls were regular skaters.
The Kinetisense system was used both to generate the proprioceptive cues and to capture the proprioceptive data. Screen shots from the Kinetisense software with a researcher subject were combined into a presentation that experimental participants watched during their testing (Figure 1). Those participants were asked to get themselves into the same postures demonstrated in the presentation, and the Kinetisense system was used to capture the postures assumed by the participants. Accuracy was determined as the difference between the assumed posture and the presentation posture for each of the pre- and post-exercise condition, and variability was determined for the assumed postures between pre- and post-exercise conditions. In this model, increased accuracy in post-exercise would demonstrate good immediate improvement in proprioception from skating exercise, while low variability amongst the skating group might suggest some long-term KP benefits from exercise.
A general trend of overshooting target angles was observed for postures where limbs were closer to the body, while less stable postures tended to be undershot. When results of the pre and post-test were compared, PD subject variance was 4.9° (compared to 5.9° and 6.3° for control and skater). The control group increased accuracy by 0.26°, but PD subject decreased accuracy by 0.18°.
Low variance for our PD participant suggests that regular vigorous physical exercise has a beneficial effect, but that benefit may be swamped by fatigue immediately after exercise (where PD participant had slightly decreased activity.
In this study, the Kinetisense system was doubly-useful - the clear picture, with overlaid stick model and dashboard information surround, made the output of the software a clear and effective postural instruction for participants, while the quick set-up and markerless motion capture makes accurate postural measurements in field settings quick and easy.
Dr. Doan’s research combines mechanical and biological engineering with kinesiology and neuroscience to focus on measuring and interpreting the interaction of human perceptions and actions at work and at play. His current research explores two main topics: 1) perceptual basis of occupational over-loading and soft tissue injury, and 2) exercise therapy and biomedical devices for neurorehabilitation amongst people living with Parkinson's disease. Dr. Doan's research combines field work with experimental studies in the Engineering and Human Performance Laboratory. Dr. Doan is currently accepting graduate students.
Dr. Doan’s course offerings include Research Methodologies (2200), Functional Biomechanics (2650), Biomechanics (3650), Work and Physical Ergonomics (4300), Advanced Biomechanics (4550), and Bioinstrumentation (4660). Dr. Doan is available to supervise both independent and applied studies courses.
Please view Dr. Doan’s for more information.