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

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.

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.

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.

Comparison between overground and dynamometer manual wheelchair propulsion.

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 with the direction and amount of force applied, the time peak force was reached, push angle, and their stroke frequency between conditions.

The influence of shoulder pain and fear of falling on level and non-level transfer technique.

BACKGROUND: Level and non-level transfers are essential tasks of daily living for wheelchair users. Minimal research has examined the role of shoulder pain and fear of falling on transfer quality. The purpose of this study is to (1) examine the association between shoulder pain, fear of falling (FoF) and transfer quality and (2) explore the feasibility of assessing non-level transfers to-and-from the floor. METHODS: Cross-sectional design was used to explore shoulder pain, FoF, and transfer quality in 30 manual wheelchair users (aged 18-42; 15 males). Participant demographic information (age, sex, race, disability, and years using wheelchair), Spinal Cord Injury-Fall Concern Scale (SCI-FCS), and Wheelchair User Shoulder Pain Index (WUSPI) was collected. Three types of transfers: (1) level, (2) uphill, and (3) floor-to-table were graded by a trained researcher using the Transfer Assessment Instrument (TAI) 3.0. Kruskal-Wallis test was used to determine differences in transfer quality based on condition. Spearman correlation was used to determine associations between demographic data, WUSPI, SCI-FCS, and transfer quality scores. RESULTS: All participants safely completed the uphill non-level transfer; 27 safely completed the floor-to-table non-level transfer. Statistical analysis revealed no difference in TAI score across transfer conditions. Spearman correlation revealed a significant correlation between WUSPI and SCI-FCS scores (r = .68, P = .01) and WUSPI and uphill TAI scores (r = -.45, P = .01). CONCLUSION: Increases in shoulder pain are related to decreased uphill transfer quality and increased FoF. Non-level transfers to-and-from the floor are feasible within clinical or laboratory settings.

Push-Rate Threshold for Physical Activity Intensity in Persons Who Use Manual Wheelchairs.

ABSTRACT: There is evidence that manual wheelchair users are among the least physically active in society. However, the current cut points for quantifying physical activity intensity based on steps per minute have been developed for ambulatory adults from the general population and other clinical populations and may not be appropriate or applicable for manual wheelchair users. This study examined the association between push rate (an analog of step rate) and energy expenditure across three speeds of treadmill wheelchair propulsion among manual wheelchair users and further generated a push-rate cut point for quantifying moderate-to-vigorous physical activity. Persons who used manual wheelchairs (N = 17) performed three, 6-min bouts of manual wheelchair propulsion on a motor-driven treadmill at speeds of 0.7, 1.3, and 2.0 m/sec. Push rate per trial was measured using SMARTwheels, and the rate of oxygen consumption per trial was measured using a portable metabolic system. The mean (SD) R2 value for the relationship between push rate and energy expenditure was 0.78 (0.14). The mean (SD) push-rate cut point for quantifying moderate-to-vigorous physical activity was 55.05 (26.06) pushes/min. This preliminary study provides the first push-rate cut point for quantifying moderate-to-vigorous physical activity among a heterogeneous sample of manual wheelchair users. This threshold may be important for public health promotion and individual-level monitoring and prescription of free-living physical activity behavior among manual wheelchair users.

Short-term influence of transfer training among full time pediatric wheelchair users: A randomized trial.

OBJECTIVE/BACKGROUND: To describe a structured, short-term, transfer training intervention for full-time pediatric wheelchair users, investigate the impact of training on transfer skills, and to examine similarities and differences in response to training compared to those seen in adult wheelchair users. DESIGN: Randomized clinical trial. METHODS: Participants were first randomized into an intervention (IG) or control group (CG). After completing surveys and demographic intake forms, all participants performed two sets of level transfers (from wheelchair to bench and back to wheelchair = one set) at three time points. Each time point composed of two transfer sets were scored using the Transfer Assessment Instrument (TAI) and averaged to produce a final transfer score per time point. No feedback or training were given to participants prior to time points one and two however the IG received structured training prior to transfer assessment # 3. TAI scores were compared at transfer assessment #3 using a Mann-Whitney test. OUTCOME MEASURES: Transfer Assessment Instrument (TAI) and Self-Perception Profile for Children (SPPC). RESULTS: Intervention group participants demonstrated significant improvements among TAI scores (9.06 ± 1.01) compared to the control group (7.15 ± 1.67), P = 0.030, d = 1.385. No significant differences were found among SPPC scores. CONCLUSION: Pediatric wheelchair users transfer skills were found to improve immediately after training with TAI score changes similar to those seen in adult wheelchair users after training. Such improvements may be a factor in long-term upper extremity preservation. Further testing is needed to examine the long-term impact of improved transfer skills.

Influence of handrim wheelchair propulsion training in adolescent wheelchair users, a pilot study.

Ten full-time adolescent wheelchair users (ages 13-18) completed a total of three propulsion trials on carpet and tile surfaces, at a self-selected velocity, and on a concrete surface, at a controlled velocity. All trials were performed in their personal wheelchair with force and moment sensing wheels attached bilaterally. The first two trials on each surface were used as pre-intervention control trials. The third trial was performed after receiving training on proper propulsion technique. Peak resultant force, contact angle, stroke frequency, and velocity were recorded during all trials for primary analysis. Carpet and tile trials resulted in significant increases in contact angle and peak total force with decreased stroke frequency after training. During the velocity controlled trials on concrete, significant increases in contact angle occurred, as well as decreases in stroke frequency after training. Overall, the use of a training video and verbal feedback may help to improve short-term propulsion technique in adolescent wheelchair users and decrease the risk of developing upper limb pain and injury.

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.

Perspectives on Physical Activity Among People with Multiple Sclerosis Who Are Wheelchair Users: Informing the Design of Future Interventions.

BACKGROUND: People with advanced multiple sclerosis (MS) are less physically active than those with milder forms of the disease, and wheelchair use has a negative association with physical activity participation. Thus, wheelchair users with MS are doubly disadvantaged for accruing the benefits of physical activity and exercise. Appropriate physical activity and exercise interventions are needed for this population. METHODS: We undertook a qualitative study to explore the meanings, motivations, and outcomes of physical activity in wheelchair users with MS. We sought to understand daily opportunities to accumulate physical activity and exercise, and to identify perceived barriers, facilitators, and benefits that might inform the design of future interventions. RESULTS: We interviewed 15 wheelchair users (mean age, 52 ± 8.8 years; n = 12 women). Data were transcribed and analyzed to identify and explore common themes. Our first theme was the reduced opportunity to participate in physical activity due to participants' dependence on mobility devices, environmental adaptations, and tangible support. Our second theme was the importance of incorporating physical activity and exercise into the everyday environment, highlighting the need for adaptive exercise and accessible environments. This indicated the need to incorporate behavior change modulators into physical activity and exercise interventions for those with advanced MS. Health-care professionals played an important role in promoting increased physical activity and exercise participation in those with advanced MS. CONCLUSIONS: Our findings may inform future interventions to increase initiation and maintenance of physical activity and exercise among people with advanced MS.

Differences in participation based on self-esteem in power and manual wheelchair users on a university campus: a pilot study.

OBJECTIVES: To examine the relationship of self-esteem and wheelchair type with participation of young adult manual and power wheelchair users with diverse physical disabilities. DESIGN: Cross-sectional survey study. SETTING: Large University Campus. PARTICIPANTS: A convenience sample of college students (N = 39) with self-reported physical disabilities who are full time wheelchair users (>40 per week) and are two or more years post illness or injury. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Rosenberg Self-Esteem Scale was used to measure self-esteem, and the Craig Handicap Assessment and Reporting Technique was used to measure participation. RESULTS: Self-esteem correlated highly with cognitive independence (CI) (r = 0.58), mobility (r = 0.67) and social integration (SI) (r = 0.52). Use of manual wheelchair was significantly related to higher levels of CI and mobility while longer use of any wheelchair (power or manual) was significantly associated with higher levels of mobility and SI. In addition higher self-esteem independently predicted a significant proportion of the variance in CI, mobility and SI, while type of wheelchair predicted a significant proportion of the variance in CI (p < 0.005). CONCLUSIONS: High self-esteem was found to be the strongest predictor of participation in a population of young adults with mobility limitations. Better understanding of the factors influencing participation may help to facilitate new interventions to minimize the disparities between persons with disabilities and their able bodied peers. Implication for Rehabilitation A total of 46.8% of wheelchair users report the desire for increased community participant but face significant barriers. The type of wheelchair has been identified as having a large impact on participation. This study found self-esteem to be the strongest predictor of participation, which is notable because self-esteem is a characteristic that is potentially modifiable with treatment.

Variability in Wheelchair Propulsion: A New Window into an Old Problem.

Manual wheelchair users are at great risk for the development of upper extremity injury and pain. Any loss of upper limb function due to pain adversely impacts the independence and mobility of manual wheelchair users. There is growing theoretical and empirical evidence that fluctuations in movement (i.e., motor variability) are related to musculoskeletal pain. This perspectives paper discusses a local review on several investigations examining the association between variability in wheelchair propulsion and shoulder pain in manual wheelchair users. The experimental data reviewed highlights that the variability of wheelchair propulsion is impacted by shoulder pain in manual wheelchair users. We maintain that inclusion of these metrics in future research on wheelchair propulsion and upper limb pain may yield novel data. Several promising avenues for future research based on this collective work are discussed.

Assessing complexity of heart rate variability in people with spinal cord injury using local scale exponents.

Detrended fluctuation analysis (DFA) has been widely used to study dynamics of heart rate variability (HRV), which provides a quantitative parameter, the scaling exponent a, to represent the correlation properties of RR interval series. However, it has been demonstrated that HRV exhibits complex behavior that cannot be fully described by a single exponent. This study aimed to investigate whether local scale exponent α(t) with t being the time scale can reveal new features of HRV that cannot be reflected by DFA coefficients. To accurately estimate α(t), we developed an approach for correcting a(t) at small scales and verified the approach using simulated signals. We studied HRV in 12 subjects with spinal cord injury and 14 able-bodied controls during sitting and prone postures. The results showed that α(t) provides complementary views of HRV, suggesting that it may be used to evaluate the effects of SCI-induced autonomic damage on HRV.

Shoulder pain and cycle to cycle kinematic spatial variability during recovery phase in manual wheelchair users: a pilot investigation.

UNLABELLED: Wheelchair propulsion plays a significant role in the development of shoulder pain in manual wheelchair users (MWU). However wheelchair propulsion metrics related to shoulder pain are not clearly understood. This investigation examined intra-individual kinematic spatial variability during semi-circular wheelchair propulsion as a function of shoulder pain in MWU. Data from 10 experienced adult MWU with spinal cord injury (5 with shoulder pain; 5 without shoulder pain) were analyzed in this study. Participants propelled their own wheelchairs on a dynamometer at 3 distinct speeds (self-selected, 0.7 m/s, 1.1 m/s) for 3 minutes at each speed. Motion capture data of the upper limbs were recorded. Intra-individual kinematic spatial variability of the steady state wrist motion during the recovery phase was determined using principal component analysis (PCA). The kinematic spatial variability was calculated at every 10% intervals (i.e at 11 interval points, from 0% to 100%) along the wrist recovery path. RESULTS: Overall, spatial variability was found to be highest at the start and end of the recovery phase and lowest during the middle of the recovery path. Individuals with shoulder pain displayed significantly higher kinematic spatial variability than individuals without shoulder pain at the start (at 10% interval) of the recovery phase (p<.004). CONCLUSIONS: Analysis of intra-individual kinematic spatial variability during the recovery phase of manual wheelchair propulsion distinguished between those with and without shoulder pain. Variability analysis of wheelchair propulsion may offer a new approach to monitor the development and rehabilitation of shoulder pain.