Ian Rice

Hand rim wheelchair propulsion training using biomechanical real-time visual feedback based on motor learning theory principles.

Abstract Background/Objective: As considerable progress has been made in laboratory-based assessment of manual wheelchair propulsion biomechanics, the necessity to translate this knowledge into new clinical tools and treatment programs becomes imperative. The objective of this study was to describe the development of a manual wheelchair propulsion training program aimed to promote the development of an efficient propulsion technique among long-term manual wheelchair users. Methods: Motor learning theory principles were applied to the design of biomechanical feedback-based learning software, which allows for random discontinuous real-time visual presentation of key spatiotemporal and kinetic parameters. This software was used to train a long-term wheelchair user on a dynamometer during 3 low-intensity wheelchair propulsion training sessions over a 3-week period. Biomechanical measures were recorded with a SmartWheel during over ground propulsion on a 50-m level tile surface at baseline and 3 months after baseline. Results: Training software was refined and administered to a participant who was able to improve his propulsion technique by increasing contact angle while simultaneously reducing stroke cadence, mean resultant force, peak and mean moment out of plane, and peak rate of rise of force applied to the pushrim after training. Conclusions: The proposed propulsion training protocol may lead to favorable changes in manual wheelchair propulsion technique. These changes could limit or prevent upper limb injuries among manual wheelchair users. In addition, many of the motor learning theory—based techniques examined in this study could be applied to training individuals in various stages of rehabilitation to optimize propulsion early on.

Handrim wheelchair propulsion training effect on overground propulsion using biomechanical real-time visual feedback.

OBJECTIVE To compare the effects of 2 manual wheelchair propulsion training programs on handrim kinetics, contact angle, and stroke frequency collected during overground propulsion. DESIGN Randomized controlled trial comparing handrim kinetics between 3 groups: a control group that received no training, an instruction-only group that reviewed a multimedia presentation, and a feedback group that reviewed the multimedia presentation and real-time visual feedback. SETTING Research laboratory. PARTICIPANTS Full-time manual wheelchair users (N=27) with spinal cord injury living in the Pittsburgh area. INTERVENTIONS Propulsion training was given 3 times over 3 weeks, and data were collected at baseline, immediately after training, and at 3 months. MAIN OUTCOME MEASURES Contact angle, stroke frequency, peak resultant force, and peak rate of rise of resultant force. RESULTS Both feedback and instruction-only groups improved their propulsion biomechanics across all surfaces (carpet, tile, and ramp) at both target and self-selected speeds compared with the control group. While controlling for velocity, both intervention groups showed long-term reductions in the peak rate or rise of resultant force, stroke frequency, and increased contact angle. CONCLUSIONS Long-term wheelchair users in both intervention groups significantly improved many aspects of their propulsion technique immediately after training and 3 months from baseline. Furthermore, training with a low-cost instructional video and slide presentation was an effective training tool alone.

Manual wheelchair stroke characteristics during an extended period of propulsion

Study Design:Cross-sectional study.Objectives:The purpose of this study was to examine stroke characteristics of long-term manual wheelchair users during an extended manual wheelchair propulsion trial and the extent to which changes in propulsion biomechanics occurred.Setting:Human Engineering Research Laboratories, VA Rehabilitation Research and Development Center, VA Pittsburgh Healthcare Systems, Pittsburgh, PA, USA.Methods:Kinetic data were recorded from 21 subjects with paraplegia at four time points over the course of a 10-min propulsion trial at a steady state speed of 1.4 m s−1. Upper extremity kinetic parameters were recorded using Smartwheels, force and torque sensing pushrims.Results:Subjects for propulsion biomechanics changed from early to late during the 10-min trial. Individuals displayed decreased maximum rate of rise of resultant force (P=0.0045) with a simultaneous increase in push time (P=0.043) and stroke time (P=0.023), whereas stroke frequency remained static. In addition, there was a decrease in out of plane moment application (P=0.032).Conclusion:Individuals seemed to naturally accommodate their propulsive stroke, using less injurious propulsion biomechanics over the course of a 10-minute trial on a dynamometer. The findings may have occurred as a result of both biomechanical compensations to a challenging propulsion trial and accommodation to propelling on a dynamometer. These results suggest that subjects may be capable of independently incorporating favorable biomechanical strategies to meet the demands of a challenging propulsion scenario.

Variability of peak shoulder force during wheelchair propulsion in manual wheelchair users with and without shoulder pain

BACKGROUND Manual wheelchair users report a high prevalence of shoulder pain. Growing evidence shows that variability in forces applied to biological tissue is related to musculoskeletal pain. The purpose of this study was to examine the variability of forces acting on the shoulder during wheelchair propulsion as a function of shoulder pain. METHODS Twenty-four manual wheelchair users (13 with pain, 11 without pain) participated in the investigation. Kinetic and kinematic data of wheelchair propulsion were recorded for 3 min maintaining a constant speed at three distinct propulsion speeds (fast speed of 1.1 m/s, a self-selected speed, and a slow speed of 0.7 m/s). Peak resultant shoulder forces in the push phase were calculated using inverse dynamics. Within individual variability was quantified as the coefficient of variation of cycle to cycle peak resultant forces. FINDINGS There was no difference in mean peak shoulder resultant force between groups. The pain group had significantly smaller variability of peak resultant force than the no pain group (P<0.01, η²=0.18). INTERPRETATION The observations raise the possibility that propulsion variability could be a novel marker of upper limb pain in manual wheelchair users.

Relationship Between Shoulder Pain And Kinetic And Temporal-Spatial Variability In Wheelchair Users

OBJECTIVE To examine intra-individual variability of kinetic and temporal-spatial parameters of wheelchair propulsion as a function of shoulder pain in manual wheelchair users (MWUs). DESIGN Cohort. SETTING University research laboratory. PARTICIPANTS Adults with physical disabilities (N=26) who use a manual wheelchair for mobility full time (>80% ambulation). INTERVENTIONS Participants propelled their own wheelchairs with force-sensing wheels at a steady-state pace on a dynamometer at 3 speeds (self-selected, 0.7m/s, 1.1m/s) for 3 minutes. Temporal-spatial and kinetic data were recorded unilaterally at the hand rim. MAIN OUTCOME MEASURES Shoulder pain was quantified with the Wheelchair Users Shoulder Pain Index. Intra-individual mean, SD, and coefficient of variation (CV=mean/SD) with kinetic and temporal-spatial metrics were determined at the handrim. RESULTS There were no differences in mean kinetic and temporal-spatial metrics as a function of pain group (P values >.016). However, individuals with pain displayed less relative variability (CV) in peak resultant force and push time than pain-free individuals (P<.016). CONCLUSIONS Shoulder pain had no influence on mean kinetic and temporal-spatial propulsion variables at the handrim; however, group differences were found in relative variability. These results suggest that intra-individual variability analysis is sensitive to pain. We propose that variability analysis may offer an approach for earlier identification of MWUs at risk for developing shoulder pain.

Accelerometer output and its association with energy expenditure during manual wheelchair propulsion

Study design:This is an experimental design.Objectives:This study examined the association between rates of energy expenditure (that is, oxygen consumption (VO2)) and accelerometer counts (that is, vector magnitude (VM)) across a range of speeds during manual wheelchair propulsion on a motor-driven treadmill. Such an association allows for the generation of cutoff points for quantifying the time spent in moderate-to-vigorous physical activity (MVPA) during manual wheelchair propulsion.Setting:The study was conducted in the University Laboratory.Methods:Twenty-four manual wheelchair users completed a 6-min period of seated rest and three 6-min periods of manual wheelchair propulsion on a motor-driven wheelchair treadmill. The 6-min periods of wheelchair propulsion corresponded with three treadmill speeds (1.5, 3.0 and 4.5 mph) that elicited a range of physical activity intensities. Participants wore a portable metabolic unit and accelerometers on both wrists. Primary outcome measures included steady-state VO2 and VM, and the strength of association between VO2 and VM was based on the multiple correlation and squared multiple correlation coefficients from linear regression analyses.Results:Strong linear associations were established between VO2 and VM for the left (R=0.93±0.44; R2=0.87±0.19), right (R=0.95±0.37; R2=0.90±0.14) and combined (R=0.94±0.38; R2=0.88±0.15) accelerometers. The linear relationship between VO2 and VM for the left, right and combined wrists yielded cutoff points for MVPA of 3659 ±1302, 3630±1403 and 3644±1339 counts min−1, respectively.Conclusion:We provide cutoff points based on the linear association between energy expenditure and accelerometer counts for estimating time spent in MVPA during manual wheelchair propulsion using wrist-worn accelerometry. The similarity across wrist location permits flexibility in selecting a location for wrist accelerometry placement.

Using local scale exponent to characterize heart rate variability in response to postural changes in people with spinal cord injury.

Heart rate variability (HRV) is a promising marker for evaluating the remaining autonomic function in people with spinal cord injury (SCI). HRV is commonly assessed by spectral analysis and detrended fluctuation analysis (DFA). This study aimed to investigate whether local scale exponent α(t) can reveal new features of HRV that cannot be reflected by spectral measures and DFA coefficients. We studied 12 participants with SCI and 15 healthy able-bodied controls. ECG signals were continually recorded during 10 min sitting and 10 min prone postures. α(t) was calculated for scales between 4 and 60 s. Because α(t) could be overestimated at small scales, we developed an approach for correcting α(t) based on previous studies. The simulation results on simulated monofractal time series with α between 0.5 and 1.3 showed that the proposed method can yield improved estimation of α(t). We applied the proposed method to raw RR interval series. The results showed that α(t) in healthy controls monotonically decreased with scale at scales between 4 and 12 s (0.083–0.25 Hz) in both the sitting and prone postures, whereas in participants with SCI, α(t) slowly decreased at almost all scales. The sharp decreasing trend in α(t) in controls suggests a more complex dynamics of HRV in controls. α(t) at scales between 4 (0.25 Hz) and around 7 s (0.143 Hz) was lower in subjects with SCI than in controls in the sitting posture; α(t) at a narrow range of scales around 12 s (0.083 Hz) was higher in participants with SCI than in controls in the prone posture. However, none of normalized low frequency (0.04–0.15 Hz) power, the ratio of low frequency power to high frequency (0.15–0.4 Hz) power and long-term (>11 beats) DFA coefficient showed significant difference between healthy controls and subjects with SCI in the prone posture. Our results suggest that α(t) can reveal more detailed information in comparison to spectral measures and the standard DFA parameters.

A sports wheelchair for low-income countries

Purpose. Appropriate wheelchairs for basic mobility needs are still not commonly available in low-income countries, although several organizations are working toward this goal. After basic mobility is secured it is important to provide more diverse assistive technology to allow people with disabilities to more completely participate in society and live healthy lives. Our goal was to design an affordable sports wheelchair that would allow individuals in low-income countries to participate in basketball. Methods. Design requirements established for the sports wheelchair included: removable anti-tippers, adjustable tension backrest, 24″ wheels, adjustable seat dump, variable camber, 4″ casters, fore-aft axle position, removable bumpers, height adjustable footrest, four wheels, single anti-tipper (pivot), cost less than

Promoting Physical Activity Through a Manual Wheelchair Propulsion Intervention in Persons With Multiple Sclerosis

125 without wheels, 16″ seat width and backrest height, and nylon upholstery. The wheelchair was designed using 3D modeling, standard materials, and standard tools. Discussion. An affordable wheelchair, versatile enough to be used for a variety of sports and even everyday use, was designed and prototyped successfully. Documentation for the design including step-by-step directions, engineering drawings, and photographs are available at the Human Engineering Research Laboratories website (http://www.herlpitt.org/intw.htm). Future work on the prototype should include design refinement including adaptations for other sports, and standards testing.

Technology to improve sports performance in wheelchair sports

OBJECTIVE To examine the efficacy and feasibility of a multifactorial intervention to increase lifestyle physical activity in nonambulatory persons with multiple sclerosis (MS) based on wheelchair optimization, propulsion skill/technique training, and behavioral strategies based on social cognitive theory. DESIGN Randomized controlled trial, 3-month postintervention follow-up. SETTING Home and general community, and university research laboratory. PARTICIPANTS Nonambulatory individuals with MS (N=14; mean age ± SD, 53.6±8.7y) were randomly assigned to an intervention group (IG) or a control group (CG). INTERVENTIONS After baseline testing, the IG participants received custom-fit, ultralightweight manual wheelchairs with propulsion/skills training, followed by 3 months of at-home use with the custom ultralightweight wheelchair and weekly phone calls to deliver support through a multifactorial intervention. The CG participants received no training and used their own wheelchairs at home during this time. MAIN OUTCOME MEASURES All subjects were assessed at baseline and 3 months later for fatigue (Fatigue Severity Scale), upper extremity strength (digital handheld dynamometer), and propulsion technique (on a treadmill [0.5m/s] with instrumented wheels). Two 1-week bouts of physical activity were measured in both groups from home with wrist-worn accelerometry at the beginning (IG and CG in own wheelchairs) and end (IG in study wheelchair, CG in own) of the 3-month period of home use. RESULTS The intervention was well tolerated, and no adverse events were reported. The IG demonstrated increased strength (P=.008) and a trend toward less fatigue (P=.068), both with large effect sizes (d>0.8), as well as reduced application of braking torque during propulsion (P=.003) with a moderate/large effect size (d=.73), compared with the CG. CONCLUSIONS Findings suggest a 3-month physical activity intervention based on manual wheelchair propulsion and training is safe and feasible for some wheelchair users living with MS and may produce secondary benefits in strength, fatigue, and propulsion technique.