Alicia Koontz - Academia.edu (original) (raw)
articles by Alicia Koontz
Papers by Alicia Koontz
BioMed research international, 2015
Disability and rehabilitation. Assistive technology, Jan 19, 2015
The purpose of this study is to describe the results of focus groups held during the Independent ... more The purpose of this study is to describe the results of focus groups held during the Independent Wheelchair Transfer (IWT) Workgroup. The aims were to facilitate exchange of ideas on (1) the impact of the built environment on the wheelchair transfer process within the community (i.e. moving from wheelchair to and from other surfaces (e.g. furniture, toilet seat, bath bench, car seat) to participate in daily activities), (2) wheelchair users' needs during transfers in the built environment, and (3) future research directions. Live web-based conferencing using Adobe Connect technology (Clarix Technologies, Inc., Pittsford, NY) was utilized to conduct three focus groups composed of experts in the field of assistive technology. Investigators independently reviewed focus group meeting transcripts and used qualitative methods to identify main themes. Thirty-one experts in assistive technology and related fields participated in focus groups. Nine main themes were found including the ef...
Topics in Spinal Cord Injury Rehabilitation, 2009
... Biomechanics of Sitting Pivot Transfers Among Individuals with a Spinal Cord Injury: A Review... more ... Biomechanics of Sitting Pivot Transfers Among Individuals with a Spinal Cord Injury: A Review of the Current Knowledge Dany Gagnon, Alicia M. Koontz, Sara J. Mulroy, Debbie A. Nawoczenski, Emelie Butler-Forslund, Anna Granstrom, Sylvie Nadeau, and Michael L. Boninger ...
BioMed research international, 2014
This study investigated (1) the effect of repetitive weight-relief raises (WR) and shoulder exter... more This study investigated (1) the effect of repetitive weight-relief raises (WR) and shoulder external rotation (ER) on the acromiohumeral distance (AHD) among manual wheelchair users (MWUs) and (2) the relationship between shoulder pain, subject characteristics, and AHD changes. Twenty-three MWUs underwent ultrasound imaging of the nondominant shoulder in an unloaded baseline position and while holding a WR position before and after the WR/ER tasks. Paired t-tests and Spearman correlational analysis were used to assess differences in the AHD before and after each task and the relationships between pain, subject characteristics, and the AHD measures. A significant reduction in the subacromial space (P<0.01) occurred when subjects performed a WR position compared to baseline. Individuals with increased years of disability had greater AHD percentage narrowing after WR (P=0.008). Increased shoulder pain was associated with AHD percentage narrowing after ER (P≤0.007). The results suppo...
BioMed research international, 2014
Transfers are one of the most physically demanding wheelchair activities. The purpose of this stu... more Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments (P < .02, model R(2) values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm...
Journal of applied biomechanics, 2012
Laboratory-based simulators afford many advantages for studying physiology and biomechanics; howe... more Laboratory-based simulators afford many advantages for studying physiology and biomechanics; however, they may not perfectly mimic wheelchair propulsion over natural surfaces. The goal of this study was to compare kinetic and temporal parameters between propulsion overground on a tile surface and on a dynamometer. Twenty-four experienced manual wheelchair users propelled at a self-selected speed on smooth, level tile and a dynamometer while kinetic data were collected using an instrumented wheel. A Pearson correlation test was used to examine the relationship between propulsion variables obtained on the dynamometer and the overground condition. Ensemble resultant force and moment curves were compared using cross-correlation and qualitative analysis of curve shape. User biomechanics were correlated (R ranging from 0.41 to 0.83) between surfaces. Overall, findings suggest that although the dynamometer does not perfectly emulate overground propulsion, wheelchair users were consistent w...
Disability and rehabilitation. Assistive technology, 2012
The purpose of this study was to perform a literature review and seek expert opinion on the relev... more The purpose of this study was to perform a literature review and seek expert opinion on the relevance and strength of the evidence concerning setup and transfer performance. Scientific literature databases were searched until June 2009 using 43 keywords resulting in 339 articles. These were internally reviewed and narrowed to 41 articles which were formally assessed by 13 external experts. Articles that 80% or more of the reviewers scored as moderately or highly relevant were included in the final results. Nineteen articles met the relevancy criteria. The aspects of setup that experts felt were addressed to some degree included vertical transfer distance, transferring across a gap and position of the mobility device relative to target destination. None of the 19 articles were scored as having strong to very strong resulting evidence. There is a consensus among studies that transferring to a higher surface implies greater exertion of the upper limb. However, there is no evidence conc...
Medical Engineering & Physics, 2001
Biomechanical signals collected during wheelchair propulsion are often analyzed by computing aver... more Biomechanical signals collected during wheelchair propulsion are often analyzed by computing averages and/or peak values over several strokes. Due to the complex nature of the signals, this type of analysis may not be specific to identifying factors that may predispose a wheelchair user to joint pain/injury. Hence, a new technique is introduced that uses a system identification approach, autoregressive (AR) modeling, to analyze wheelchair propulsion force waveforms. In this application an AR method was used to create a model force waveform based on current and past values of digital pushrim force data. The feasibility of the AR modeling method over point-wise methods to detect asymmetry among force waveforms was tested with a group of 20 wheelchair users. Subjects propelled at a constant 0.9 m/s on a roller system during which 20 s of force data were collected from the SMART(Wheel)s, force and torque sensing pushrims. Both methods showed that the wheelchair users as a group propelled evenly, however, individual analysis using the AR model error estimates indicated that twenty-five percent demonstrated significant asymmetry in their force waveforms. If only point-wise means and variances of the applied bilateral forces were considered, most subjects would have appeared symmetrical. Thus, the AR modeling approach is more sensitive to detecting anomalies in propulsion technique.
The Journal of Rehabilitation Research and Development, 2009
The Journal of Rehabilitation Research and Development, 2005
The Journal of Rehabilitation Research and Development, 2007
International Journal of Industrial Ergonomics, 2004
IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2001
Due to the high incidence of secondary wrist injury among manual wheelchair users, recent emphasi... more Due to the high incidence of secondary wrist injury among manual wheelchair users, recent emphasis has been placed on the investigation of wheelchair propulsion biomechanics. Accurate representation of wrist activity during wheelchair propulsion may help to elucidate the mechanisms contributing to the development of wrist injuries. Unfortunately, no consensual wrist biomechanical model has been established. In order to determine if different methodologies obtain similar results, this investigation created and compared three different wrist models: 1) a fixed joint center placed between the styloids (midstyloid joint center); 2) a joint center with 2 degrees of freedom computed from de Leva's joint center data; and 3) a floating joint center. Results indicate that wrist flexion and extension angles are highly consistent between models, however, radial and ulnar deviation angles vary considerably. Mean maximum right flexion angles were found to be 3.5 degrees, 2.2 degrees, and 5.0 degrees for the midstyloid, de Leva, and floating joint center models, respectively. Extension angles were 22.3 degrees, 23.6 degrees, and 23.6 degrees, respectively. Mean maximum right radial deviation angles for the midstyloid, de Leva, and floating joint center models were 26.0 degrees, 26.9 degrees, and 45.1 degrees, respectively, and ulnar deviation angles were found to be 30.5 degrees, 38.8 degrees, and 10.2 degrees, respectively. This information is useful when comparing kinematic studies and further supports the need for consensual methodology.
IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2000
With about 2.2 million Americans currently using wheeled mobility devices, wheelchairs are freque... more With about 2.2 million Americans currently using wheeled mobility devices, wheelchairs are frequently provided to people with impaired mobility to provide accessibility to the community. Individuals with spinal cord injuries, arthritis, balance disorders, and other conditions or diseases are typical users of wheelchairs. However, secondary injuries and wheelchair-related accidents are risks introduced by wheelchairs. Research is underway to advance wheelchair design to prevent or accommodate secondary injuries related to propulsion and transfer biomechanics, while improving safe, functional performance and accessibility to the community. This paper summarizes research and development underway aimed at enhancing safety and optimizing wheelchair design.
Clinical Biomechanics, 2006
Clinical Biomechanics, 2006
BioMed research international, 2015
Disability and rehabilitation. Assistive technology, Jan 19, 2015
The purpose of this study is to describe the results of focus groups held during the Independent ... more The purpose of this study is to describe the results of focus groups held during the Independent Wheelchair Transfer (IWT) Workgroup. The aims were to facilitate exchange of ideas on (1) the impact of the built environment on the wheelchair transfer process within the community (i.e. moving from wheelchair to and from other surfaces (e.g. furniture, toilet seat, bath bench, car seat) to participate in daily activities), (2) wheelchair users' needs during transfers in the built environment, and (3) future research directions. Live web-based conferencing using Adobe Connect technology (Clarix Technologies, Inc., Pittsford, NY) was utilized to conduct three focus groups composed of experts in the field of assistive technology. Investigators independently reviewed focus group meeting transcripts and used qualitative methods to identify main themes. Thirty-one experts in assistive technology and related fields participated in focus groups. Nine main themes were found including the ef...
Topics in Spinal Cord Injury Rehabilitation, 2009
... Biomechanics of Sitting Pivot Transfers Among Individuals with a Spinal Cord Injury: A Review... more ... Biomechanics of Sitting Pivot Transfers Among Individuals with a Spinal Cord Injury: A Review of the Current Knowledge Dany Gagnon, Alicia M. Koontz, Sara J. Mulroy, Debbie A. Nawoczenski, Emelie Butler-Forslund, Anna Granstrom, Sylvie Nadeau, and Michael L. Boninger ...
BioMed research international, 2014
This study investigated (1) the effect of repetitive weight-relief raises (WR) and shoulder exter... more This study investigated (1) the effect of repetitive weight-relief raises (WR) and shoulder external rotation (ER) on the acromiohumeral distance (AHD) among manual wheelchair users (MWUs) and (2) the relationship between shoulder pain, subject characteristics, and AHD changes. Twenty-three MWUs underwent ultrasound imaging of the nondominant shoulder in an unloaded baseline position and while holding a WR position before and after the WR/ER tasks. Paired t-tests and Spearman correlational analysis were used to assess differences in the AHD before and after each task and the relationships between pain, subject characteristics, and the AHD measures. A significant reduction in the subacromial space (P<0.01) occurred when subjects performed a WR position compared to baseline. Individuals with increased years of disability had greater AHD percentage narrowing after WR (P=0.008). Increased shoulder pain was associated with AHD percentage narrowing after ER (P≤0.007). The results suppo...
BioMed research international, 2014
Transfers are one of the most physically demanding wheelchair activities. The purpose of this stu... more Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments (P < .02, model R(2) values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm...
Journal of applied biomechanics, 2012
Laboratory-based simulators afford many advantages for studying physiology and biomechanics; howe... more Laboratory-based simulators afford many advantages for studying physiology and biomechanics; however, they may not perfectly mimic wheelchair propulsion over natural surfaces. The goal of this study was to compare kinetic and temporal parameters between propulsion overground on a tile surface and on a dynamometer. Twenty-four experienced manual wheelchair users propelled at a self-selected speed on smooth, level tile and a dynamometer while kinetic data were collected using an instrumented wheel. A Pearson correlation test was used to examine the relationship between propulsion variables obtained on the dynamometer and the overground condition. Ensemble resultant force and moment curves were compared using cross-correlation and qualitative analysis of curve shape. User biomechanics were correlated (R ranging from 0.41 to 0.83) between surfaces. Overall, findings suggest that although the dynamometer does not perfectly emulate overground propulsion, wheelchair users were consistent w...
Disability and rehabilitation. Assistive technology, 2012
The purpose of this study was to perform a literature review and seek expert opinion on the relev... more The purpose of this study was to perform a literature review and seek expert opinion on the relevance and strength of the evidence concerning setup and transfer performance. Scientific literature databases were searched until June 2009 using 43 keywords resulting in 339 articles. These were internally reviewed and narrowed to 41 articles which were formally assessed by 13 external experts. Articles that 80% or more of the reviewers scored as moderately or highly relevant were included in the final results. Nineteen articles met the relevancy criteria. The aspects of setup that experts felt were addressed to some degree included vertical transfer distance, transferring across a gap and position of the mobility device relative to target destination. None of the 19 articles were scored as having strong to very strong resulting evidence. There is a consensus among studies that transferring to a higher surface implies greater exertion of the upper limb. However, there is no evidence conc...
Medical Engineering & Physics, 2001
Biomechanical signals collected during wheelchair propulsion are often analyzed by computing aver... more Biomechanical signals collected during wheelchair propulsion are often analyzed by computing averages and/or peak values over several strokes. Due to the complex nature of the signals, this type of analysis may not be specific to identifying factors that may predispose a wheelchair user to joint pain/injury. Hence, a new technique is introduced that uses a system identification approach, autoregressive (AR) modeling, to analyze wheelchair propulsion force waveforms. In this application an AR method was used to create a model force waveform based on current and past values of digital pushrim force data. The feasibility of the AR modeling method over point-wise methods to detect asymmetry among force waveforms was tested with a group of 20 wheelchair users. Subjects propelled at a constant 0.9 m/s on a roller system during which 20 s of force data were collected from the SMART(Wheel)s, force and torque sensing pushrims. Both methods showed that the wheelchair users as a group propelled evenly, however, individual analysis using the AR model error estimates indicated that twenty-five percent demonstrated significant asymmetry in their force waveforms. If only point-wise means and variances of the applied bilateral forces were considered, most subjects would have appeared symmetrical. Thus, the AR modeling approach is more sensitive to detecting anomalies in propulsion technique.
The Journal of Rehabilitation Research and Development, 2009
The Journal of Rehabilitation Research and Development, 2005
The Journal of Rehabilitation Research and Development, 2007
International Journal of Industrial Ergonomics, 2004
IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2001
Due to the high incidence of secondary wrist injury among manual wheelchair users, recent emphasi... more Due to the high incidence of secondary wrist injury among manual wheelchair users, recent emphasis has been placed on the investigation of wheelchair propulsion biomechanics. Accurate representation of wrist activity during wheelchair propulsion may help to elucidate the mechanisms contributing to the development of wrist injuries. Unfortunately, no consensual wrist biomechanical model has been established. In order to determine if different methodologies obtain similar results, this investigation created and compared three different wrist models: 1) a fixed joint center placed between the styloids (midstyloid joint center); 2) a joint center with 2 degrees of freedom computed from de Leva's joint center data; and 3) a floating joint center. Results indicate that wrist flexion and extension angles are highly consistent between models, however, radial and ulnar deviation angles vary considerably. Mean maximum right flexion angles were found to be 3.5 degrees, 2.2 degrees, and 5.0 degrees for the midstyloid, de Leva, and floating joint center models, respectively. Extension angles were 22.3 degrees, 23.6 degrees, and 23.6 degrees, respectively. Mean maximum right radial deviation angles for the midstyloid, de Leva, and floating joint center models were 26.0 degrees, 26.9 degrees, and 45.1 degrees, respectively, and ulnar deviation angles were found to be 30.5 degrees, 38.8 degrees, and 10.2 degrees, respectively. This information is useful when comparing kinematic studies and further supports the need for consensual methodology.
IEEE Transactions on Neural Systems and Rehabilitation Engineering, 2000
With about 2.2 million Americans currently using wheeled mobility devices, wheelchairs are freque... more With about 2.2 million Americans currently using wheeled mobility devices, wheelchairs are frequently provided to people with impaired mobility to provide accessibility to the community. Individuals with spinal cord injuries, arthritis, balance disorders, and other conditions or diseases are typical users of wheelchairs. However, secondary injuries and wheelchair-related accidents are risks introduced by wheelchairs. Research is underway to advance wheelchair design to prevent or accommodate secondary injuries related to propulsion and transfer biomechanics, while improving safe, functional performance and accessibility to the community. This paper summarizes research and development underway aimed at enhancing safety and optimizing wheelchair design.
Clinical Biomechanics, 2006
Clinical Biomechanics, 2006
Assistive Technology, 2006