Wheelchair users' perceived exertion during typical mobility activities

Effect of Manual Wheelchair Type on Mobility Performance, Cardiorespiratory Responses, and Perceived Exertion

This study is aimed at comparing the design and configuration of the most commonly used manual wheelchair models through cardiorespiratory responses, perceived exertion, and mobility performance using two different manual wheelchairs, during mobility tasks. A within-group 2 × 3 × 2 controlled experiment was designed with three independent and four dependent variables. The independent variables included wheelchairs, with the levels active wheelchair with a rigid frame and passive wheelchair with foldable frame; conditions with the levels straight line, slalom, and agility; and speed with levels comfortable and fast. Dependent variables included oxygen uptake (VO₂), distance travelled, speed, and perceived exertion. Results show that the active wheelchair yielded more beneficial characteristics although only the effect of wheelchair type on VO₂ efficiency (oxygen uptake per meter travelled) was statistically significant with a large effect size (F(1, 14) = 118.298, p < 0.001, η² = 0.541). The better VO₂ efficiency was achieved with the active wheelchair under all tested conditions. The effect of wheelchair type on Borg scores was also statistically significant, although with a small effect size (F(1, 14) = 10.340, p = 0.006, η² = 0.119); thus, active wheelchair use had lower Borg scores under all trials and was considered less exhausting than the passive wheelchair. In summary, use of the active wheelchair resulted in the users expending less energy per meter travelled and at the same time experiencing less fatigue. This may benefit overall wheelchair mobility and possibly reduce health complications.

Effects of Paraplegia Fitness Integrated Training on Physical Function and Exercise Self-Efficacy and Adherence Among Individuals With Spinal Cord Injury

Objective

To determine the effects of the Paraplegia Fitness Integrated Training (PARAFiT) program, which is an integrated graded physical exercise and health education program for individuals with spinal cord injury (SCI).

Methods

This nonrandomized single-blind study included 44 participants, who were assigned to either an intervention (PARAFiT) group or an active control (conventional physiotherapy) group. The intervention group underwent the PARAFiT program (8 weeks), which consisted of circuit-based interval training, progressive upper limb resistance training, and health education sessions. During the unsupervised period, the intervention group continuously underwent health education program once a month for 2 months (8 weeks). Repeated-measures analysis of variance was used for the analysis.

Results

The intervention group presented with a higher level of physical activity than did the control group; however, the difference was not significant (p=0.36). Additionally, the intervention group presented with better exercise self-efficacy and cardiorespiratory fitness and stronger bilateral shoulder muscle and handgrip than did the control group (all p<0.05). Exercise adherence was higher in the intervention group than in the control group during both the supervised (80% vs. 75%) and unsupervised (40% vs. 20%) periods.

Conclusion

The PARAFiT program enhanced the level of physical activity, exercise self-efficacy, physical fitness, and exercise adherence among the patients with SCI. Future studies should incorporate guidelines for home-based exercises and regular monitoring to promote long-term adherence to exercise and physical activity among individuals with SCI.

Effect of Phase Change Material Cooling Vests on Body Thermoregulation and Thermal Comfort of Patients With Paraplegia: A Human Subject Experimental Study

STUDY DESIGN

Randomized experimental study.

OBJECTIVE

Compared to able-bodied people, patients with paraplegia due to thoracic spinal cord injury (SCI) are at an increased risk of heat illnesses during exercise due to impaired thermoregulatory responses. To overcome this limitation, we investigated the performance of three phase change material (PCM) cooling vests of different melting temperatures (Eijsvogels, #49) and coverage area of the trunk.

METHODS

Sixteen participants were divided into three groups according to their injury level. All were tested for V20 full vest (20°C Tm, 75% coverage). Mid-thoracic and high-thoracic groups were tested for V14 vest (14°C Tm, 75% coverage). The mid-thoracic group was tested for V20 half vest (20°C Tm, 50% coverage). The participants performed a 30-min arm-crank exercise followed by a recovery period inside a controlled hot climatic chamber. The heart rate, segmental skin (Tskin), and core temperature (Tcore) values were recorded, and subjective questionnaires were taken.

RESULTS

Compared to no vest (NV) test, all the vests showed an effective decrease in Tskin values of the trunk. However, the decrease in Tskin was not enough to induce a significant decrease in Tcore in all three groups. Mid-thoracic and low-thoracic groups showed a reduction in the increasing Tcore by the end of the exercise and recovery period. Finally, the level of thermal comfort was enhanced for the three groups.

CONCLUSION

The effectiveness of cooling vests for persons with paraplegia is dependent on injury level and thus the ratio of sensate to insensate skin. Future studies necessitate the investigation of the cooling effects of PCM vests at a lower Tm with a larger sample size.

Investigating the test-retest reliability of Illinois Agility Test for wheelchair users

The Illinois Agility Test (IAT) is a standard agility course used to assess and train able-bodied athletes as well as wheelchair-sport athletes and rehabilitation of wheelchair users. It has been shown to be a reliable and valid tool to assess the able-bodied population, but the reliability of this test for assessing wheelchair propulsion has never been shown. The purpose of this study is to investigate the test-retest reliability of IAT to assess wheelchair propulsion. In this paper, the test-retest reliability of using IAT for wheelchair users is found for peak and average velocity, acceleration, tangential and total force of the push, each for the left and the right wheel. Each of these variables was found for thirty-two decisive points throughout the IAT path. The Intra-class Correlation Coefficient (ICC) was found to be very strong for 15 out of 16 variables. The average ICC was 89% and the average 95% confidence interval was [44% 96%]. In addition, thirty-seven other significant propulsion parameters were found that are clinically important, such as the number of pushes participants take to go around cones on the right, relative to turning around the cones on the left. Also, all thirty-seven variables were compared between the two sessions using four separate MANOVAs; the results showed no significant difference between IAT performed in the two sessions which were at least one week apart. This, in turn, backs the reliability of IAT for wheelchair users. These results are sufficient evidence to show that IAT is a reliable tool to test wheelchair agility for fifteen variables tested for non-wheelchair users. Since experienced wheelchair users are much more consistent in wheelchair propulsion compared to non-wheelchair-users, the results of this study show that IAT can be used as a reliable tool to assess and train wheelchair users, both for clinical and athletic applications.

Experimental study on the effectiveness of the PCM cooling vest in persons with paraplegia of varying levels

Persons with paraplegia (PA) from thoracic spinal cord injury (T1-T12) are prone to thermal stress during exercise due to impaired thermoregulation. This study evaluates the effectiveness of phase change material (PCM) cooling vests on persons with PA of different levels of injury during exercise in hot exposure. Sixteen participants were recruited and divided to three groups based on injury level; high-thoracic T1-T3, mid-thoracic T4-T8, and low thoracic T9-T12 to perform a 30-min arm-crank exercise at a 30 °C room condition. Two types of PCM vests at melting temperature of 20 °C were tested: i) V1 with PCM covering the trunk of 3.4 kg overall vest mass and ii) V2 with PCM covering chest and upper back of 2.17 kg overall vest mass. High thoracic and low-thoracic groups performed NV and V1 tests; whereas, mid-thoracic group performed NV, V1, and V2 tests. Heart rate, core, and skin temperatures were monitored during 15-min preconditioning, 30-min exercise, and 15-min recovery. In addition, thermal comfort, sensation, skin wettedness, and perceived exertion were recorded during exercise only. The main findings were that the effectiveness of the cooling vest was dependent on injury level and portion of sensate skin of trunk covered by the PCM packets. Rise in core temperature (ΔT_cr) was reduced significantly for the low-thoracic group during exercise and recovery (ΔT_cr=0.41°C, 0.26°C for NV and V1; respectively, p<0.05). For the mid-thoracic group, both V1 (p = 0.001) and V2 (p = 0.008) were effective in reducing ΔT_cr compared to the NV test at the end of the recovery period (0.74°C,0.42°C,0.56°C, for NV, V1 and V2; respectively). For the high-thoracic group, V1 was not effective in reducing core temperature (p>0.05). For the mid-thoracic group, V2 at 36% lower mass significantly improved thermal comfort (p = 0.0004) compared to the NV test and was as effective compared to V1 in reducing core temperature.

Start-up propulsion biomechanics changes with fatiguing activity in persons with spinal cord injury

Objective: Shoulder pathology is a common condition in wheelchair users that can considerably impact quality of life. Shoulder muscles are prone to fatigue, but it is unclear how fatigue affects start-up propulsion biomechanics. This study determines acute changes in start-up wheelchair propulsion biomechanics at the end of a fatiguing propulsion protocol. Design: Quasi-experimental one-group pretest-postest design. Setting: Biomechanics laboratory. Participants: Twenty-six wheelchair users with spinal cord injury (age: 35.5 ± 9.8 years, sex: 73% males and 73% with a paraplegia). Interventions: Protocol of 15 min including maximum voluntary propulsion, right- and left turns, full stops, start-up propulsion, and rests. Outcome measures: Maximum resultant force, maximum rate of rise of applied force, mean velocity, mean fraction of effective force, and mean contact time at the beginning and end of the protocol during start-up propulsion. Results: There was a significant reduction in maximum resultant force (P < 0.001) and mean velocity (P < 0.001) at the end of the protocol. Also, contact time was reduced in the first stroke of start-up propulsion (P < 0.001). Finally, propelling with a shorter contact time was associated with a greater reduction in performance (maximum velocity) at the end of the protocol. Conclusion: There are clear changes in overground propulsion biomechanics at the end of a fatiguing propulsion protocol. While reduced forces could protect the shoulder, these reduced forces come with shorter contact times and lower velocity. Investigating changes in start-up propulsion biomechanics with fatigue could provide insight into injury risk.

Use of actigraphy to measure real-world physical activities in manual wheelchair users

Introduction

The benefits of physical activity for manual wheelchair users are well-known. The purpose of this study was to validate actigraphy to objectively measure physical activity intensity among manual wheelchair users.

Method

An experimental design was used. Adult manual wheelchair users wore a GT3X actigraph on their non-dominant arm while completing eight physical activities of low (reading), moderate (propelling -- flat) and high (propelling -- steep ramp) intensity. Heart rate and rating of perceived exertion were collected at the end of each physical activity. Distribution of data were examined and used to determine the type of repeated measures (parametric vs. non-parametric). A categorical principal component analysis was performed to determine the amount of variability explained by actigraphy, heart rate and rating of perceived exertion. Activity count cut-points were estimated using bootstrapping methods.

Results

Twenty-eight manual wheelchair users completed the study. Actigraphy, heart rate and rating of perceived exertion co-varied as physical activity intensity changed. Activity counts for low-intensity and medium-intensity physical activities were estimated to be 0 to 45 and 45 to 100 activity counts per second, respectively. Activity counts' ranges for high-intensity physical activities were not clear.

Conclusion

Combining actigraphy and rating of perceived exertion could be an easy and reliable method to measure the intensity of real-world activities. Further research is needed confirm cut-points for physical activity intensity.

Intensity of physical activity as a percentage of peak oxygen uptake, heart rate and Borg RPE in motor-complete para- and tetraplegia

Objective

The aims were to describe VO_2peak, explore the potential influence of anthropometrics, demographics and level of physical activity within each cohort; b) to define common, standardized activities as percentages of VO_2peak and categorize these as light, moderate and vigorous intensity levels according to present classification systems, and c) to explore how clinically accessible methods such as heart-rate monitoring and Borg rating of perceived exertion (RPE) correlate or can describe light, moderate and vigorous intensity levels.

Design

Cross sectional.

Setting

Rehabilitation facility and laboratory environment.

Subjects

Sixty-three individuals, thirty-seven (10 women) with motor-complete paraplegia (MCP), T7-T12, and twenty-six (7 women) with motor-complete tetraplegia (MCT), C5-C8.

Interventions

VO_2peak was obtained during a graded peak test until exhaustion, and oxygen uptake during eleven different activities was assessed and categorized using indirect calorimetry.

Main outcome measures

VO_2peak, Absolute and relative oxygen consumption, Borg RPE.

Results

Absolute VO_2peak was significantly higher in men than in women for both groups, with fairly small differences in relative VO_2peak. For MCP sex, weight and time spent in vigorous-intensity activity explained 63% of VO_2peak variance. For MCT sex and time in vigorous-intensity activity explained 55% of the variance. Moderate intensity corresponds to 61–72% HR_peak and RPE 10–13 for MCP vs. 71–79% HR_peak, RPE 13–14 for MCT.

Conclusion

Using current classification systems, eleven commonly performed activities were categorized in relative intensity terms, (light, moderate and vigorous) based on percent of VO_2peak, HR_peak and Borg RPE. This categorization enables clinicians to better guide persons with SCI to meet required physical activity levels.

The Effect of Manual Wheelchair Propulsion Speed on Users' Shoulder Muscle Coordination Patterns in Time-Frequency and Principal Component Analysis

A rehabilitation program for wheelchair users should be based on a thorough understanding of shoulder muscle coordination patterns. The objective of the study was to quantify the extent to which the muscle electromyographic (EMG) patterns vary with propulsion speed. A total of 11 wheelchair-dependent participants with a diagnosis of spina bifida or T6-T12 spinal cord injury volunteered for the study. Each participant performed a series of wheelchair propulsion bouts at 1m/s, 1.3 m/s, and 1.6m/s. EMG signals of 8 shoulder muscles as well as the physiological and kinetic variables were recorded. Propulsion at 1.6m/s generated significantly higher EMG intensities in biceps brachii, anterior deltoid, pectoralis major, and middle deltoid than at 1m/s and 1.3m/s. The combined wavelet and principal component analysis showed that the faster propulsion speed requires higher push muscle activity in the early push phase and in the phase transitions between alternating push and recovery. Training to strengthen the shoulder flexors to achieve smoother phase transitions could improve rehabilitation outcomes by increasing functional speed while lessening shoulder strain.

Sex differences in wheelchair propulsion biomechanics and mechanical efficiency in novice young able-bodied adults

An awareness of sex differences in gait can be beneficial for detecting the early stages of gait abnormalities that may lead to pathology. The same may be true for wheelchair propulsion. The aim of this study was to determine the effect of sex on wheelchair biomechanics and mechanical efficiency in novice young able-bodied wheelchair propulsion. Thirty men and 30 women received 12  min of familiarisation training. Subsequently, they performed two 10-m propulsion tests to evaluate comfortable speed (CS). Additionally, they performed a 4-min submaximal propulsion test on a treadmill at CS, 125% and 145% of CS. Propulsion kinetics (via Smart^wheel) and oxygen uptake were continuously measured in all tests and were used to determine gross mechanical efficiency (GE), net efficiency (NE) and fraction of effective force (FEF). Ratings of perceived exertion (RPE) were assessed directly after each trial. Results indicated that CS for men was faster (0.98 ± 0.24 m/s) compared to women (0.71 ± 0.18 m/s). A lower GE was found in women compared to men. Push percentage, push angle and local RPE were different across the three speeds and between men and women. NE and FEF were not different between groups. Thus, even though their CS was lower, women demonstrated a higher locally perceived exertion than men. The results suggest sex differences in propulsion characteristics and GE. These insights may aid in optimising wheelchair propulsion through proper training and advice to prevent injuries and improve performance. This is relevant in stimulating an active lifestyle for those with a disability.

Wheelchair use in ultra-lightweight wheelchair users

PURPOSE

The goal of this study was to describe how ultra-lightweight wheelchair users use their wheelchairs during everyday mobility.

METHOD

We instrumented a convenience sample of 69 ultra-lightweight wheelchair users with a seat switch to measure their occupancy, and an accelerometer on their wheel to measure distance wheeled, time spent wheeling and daily bouts of mobility.

RESULTS

On the median day, subjects wheeled 83 bouts and 1.4 km over 45 min. A typical bout of mobility was 8.3 m in length, lasting 20 s and occurring at a speed of 0.44 m/s. Fast (>1 m/s) and long (>2 min) bouts represented less than 4% of bouts and were more common among younger participants and those who were employed or a student.

CONCLUSIONS

Highly functional manual wheelchair users present with a significant mobility disability, moving far less than their ambulating peers despite moving with similar mobility characteristics. The typical bout characteristics - short and slow bouts - are consistent with indoor mobility and transitions between functional activities. For wheelchair users, it highlights the importance of manoeuverability and the need for prescription and training to emphasize manoeuverability. Implications for Rehabilitation Measurement of wheelchair use, both how and how much, might provide unique insight to what equipment would be most appropriate for an individual. Participants who used an ultralight wheelchair presented with a significant mobility disability, wheeling only 1.7 km/day on average. Fast (>1 m/s) and long (>2 min) bouts are uncommon, representing less than 4% of bouts. Younger participants and those who were employed or a student were more likely to wheel one fast and long bout per day. Because wheelchair mobility was dominated by short, slow bouts, prescription and training need to emphasize maneuverability.

Objective and subjective methods for quantifying training load in wheelchair basketball small-sided games

The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards' training load and Stagno's training impulses (TRIMP_MOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards' training load and TRIMP_MOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other.