Bonita Sawatzky

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This faculty member is currently not looking for graduate students or Postdoctoral Fellows. Please do not contact the faculty member with any such requests.

Associate Professor

Research Classification

Research Interests

Outcome measures

Relevant Thesis-Based Degree Programs


Research Methodology

motion analysis
energy expenditure
online database

Graduate Student Supervision

Doctoral Student Supervision

Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.

Effects of motor skill-based wheelchair propulsion training on biomechanics, gross mechanical efficiency, and variability in older adults (2019)

Older adults are the largest cohort of manual wheelchair users (MWUs); yet, no studies have examined the effects of wheelchair propulsion training with this population. Various practice and training protocols have demonstrated mixed results related to biomechanics and efficiency when applied to younger able-bodied populations; however, their validity for older adult MWUs is unknown. Older adult MWUs are at risk of decreased participation, low confidence, and wheelchair abandonment; therefore, effective training strategies are needed for this population. The objectives of this study were to: (1) examine the effectiveness of existing handrim wheelchair propulsion practice and training protocols; (2) determine the effect of motor skill-based wheelchair propulsion training in older adults on (i) wheeling biomechanics, (ii) gross mechanical efficiency (GME), and (iii) intercycle variability; and (3) determine the effect of motor-skill based wheelchair propulsion training for older adults with mobility disabilities.Methods: Studies evaluating the effect of wheelchair propulsion practice or training protocols were systematically reviewed and meta-analyzed. The effect of motor skill-based training in able-bodied older adults compared to active (uninstructed practice) and inactive control groups was examined with a 3-arm RCT (n=34). The effect of motor skill-based training was compared to uninstructed practice in two individuals with mobility-related disabilities within a single subject research design study. Results: Significant medium effects of practice and training protocols for pre-post design studies were observed for push angle, push frequency, and GME. The motor skill-based training resulted in increased push angle and decreased push frequency, which were transferable to over-ground wheeling and retained two-weeks post training. Although there were no improvements in GME, a trend towards increased work per push following training was observed. Intercycle variability did not change based on training; however, nearly all participants in the training group modified their wheeling pattern from the arc to semi-circular pattern. Lastly, both older adult participants with mobility disabilities increased their push angles and decreased their push frequencies and peak negative forces.Conclusion: Motor skill-based wheelchair propulsion training is an effective means of improving handrim wheelchair propulsion biomechanics among novice older adult MWUs, which may help reduce overuse injuries in older MWUs.

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Master's Student Supervision

Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.

Vibration, Static Standing, Dynamic Standing, and Spasticity in Individuals with Spinal Cord Injury (2014)

Spasticity is a common consequence of upper motor neuron lesions such as spinal cord injury (SCI). Spasticity is experienced by 65-78% of individuals with SCI. Spasticity management is one of the most important challenges that clinicians and researchers encounter. Physical therapy techniques are the essential component of spasticity management that are used during and after other spasticity management tools. Vibration and standing training are two physiotherapy techniques that might be beneficial to manage spasticity in individuals with SCI. This thesis is divided into two major parts to study how these two physiotherapy techniques are useful to manage spasticity in individuals with SCI. The first study was a systemic review exploring how effective whole body and focal vibration are for spasticity management in individuals with SCI. The second study was a cross-over study that evaluated the difference between the effects of static and dynamic (using the Segway) standing training on spasticity immediately and one hour after the interventions in individuals with SCI. Spasticity was measured by three different outcome measures including self-assessment (visual analog scale), clinical (Modified Ashworth Scale), and electrophysiologic (electromyography) measures. There was evidence to support the decreasing effects of either whole body or focal vibration on spasticity in individuals with SCI. There was no statistically significant difference between the dynamic and static standing interventions for spasticity reduction. We concluded that vibration (focal and whole body) has promising effects for spasticity reduction in individuals with SCI. We also concluded that dynamic standing training has no greater effect on spasticity reduction compared to the static standing training.

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On Spasticity in Spinal Cord Injury: The Challenge of Measurement and the Role of Novel Intervention (Segway) (2010)

Spasticity is a common sequale of spinal cord injury (SCI), and can have both beneficial and detrimental effects on mobility, functional independence and self-esteem. Clinical measurement of spasticity suffers from questions of credibility and contextual isolation. Recently self-report measures of spasticity have gained recognition as a viable alternative to independent examiner techniques. This pilot study endeavored to discern whether agreement was present between the clinical ‘gold standard’ measure (the modified Ashworth scale or MAS) and a recently validated self-report tool (the Spinal Cord Injury Spasticity Evaluation Tool or SCI-SET).Spearman rank correlational analysis of measurement of spasticity using MAS and SCI-SET demonstrated some agreement, particularly with respect to the upper extremity musculature (ρ=.564, p=0.001). This relationship was much weaker comparing the lower extremity (ρ=.249, p=.161). They appear to measure similar, yet distinct aspects of the patients’ spasticity. While the MAS is quick and offers an objective interpretation, perhaps the SCI-SET better reflects the multifaceted nature of spasticity and how it affects the individual, and may enable some interpretation regarding the upper and lower extremities. This information is helpful for clinicians to compile a more comprehensive picture of spasticity as it affects the individual.The Segway Personal Transporter® is a novel, yet practical mobility tool which has yet to garner widespread support in the SCI population. It requires minimal functional ability to operate, and is appropriate for use in individuals with disabilities. Previous work suggests a possible link between the Segway and physiologic benefits to spasticity, pain and fatigue. A one month intervention program targeted these outcome measures to determine (1) if they exist and (2) whether the effects are immediate or long-term in nature.The Segway provides evidence for short term reductions in clinical ratings of spasticity (p=.001) and self-report pain (p=.027). Self-evaluations of fatigue approached significance (p=.12). There is some evidence to suggest that these beneficial outcomes may have lasting effects. The Segway may provide an adjunct to current therapy options for treating spasticity by introducing a stimulus to the system which overrides some underlying mechanism(s). As this was pilot work, further investigation of a longitudinal nature with a larger sample size is required to substantiate these findings.

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Member of G+PS
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Vancouver General Hospital

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