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This study investigated the effect of increased rolling resistance on wheelchair sprint performance and the concomitant force–velocity characteristics. Thirteen wheelchair rugby (WCR) athletes completed five 15 s wheelchair sprints in their own rugby wheelchair on an instrumented dual-roller wheelchair ergometer. The first sprint was performed against a close to overground resistance and in each of the following sprints, the resistance increased with 80% of that resistance. A repeated-measures ANOVA examined differences between sprints. Subsequently, linear regression analyses examined the individual force–velocity relations and then, individual parabolic power output curves were modeled. Increased rolling resistance led to significantly lower velocities (−36%), higher propulsion forces (+150%) and higher power outputs (+83%). These differences were accompanied by a lower push frequency, higher push time, yet a constant recovery time and contact angle. The modeled linear regressions (R2 = 0.71 ± 0.10) between force and velocity differed a lot in slope and intercept among individual athletes. The peak of the power output parabola (i.e., the optimal velocity) occurred on average at 3.1 ± 0.6 ms−1. These individual force–velocity profiles can be used for training recommendations or technological changes to better exploit power generation capabilities of the WCR athletes' musculoskeletal system.

The use of a manual wheelchair is critical to 1% of the world's population. Human powered wheeled mobility research has considerably matured, which has led to improved research techniques becoming available over the last decades. To increase the understanding of wheeled mobility performance, monitoring, training, skill acquisition, and optimization of the wheelchair-user interface in rehabilitation, daily life, and sports, further standardization of measurement set-ups and analyses is required. A crucial stepping-stone is the accurate measurement and standardization of external power output (measured in Watts), which is pivotal for the interpretation and comparison of experiments aiming to improve rehabilitation practice, activities of daily living, and adaptive sports. The different methodologies and advantages of accurate power output determination during overground, treadmill, and ergometer-based testing are presented and discussed in detail. Overground propulsion provides the most externally valid mode for testing, but standardization can be troublesome. Treadmill propulsion is mechanically similar to overground propulsion, but turning and accelerating is not possible. An ergometer is the most constrained and standardization is relatively easy. The goal is to stimulate good practice and standardization to facilitate the further development of theory and its application among research facilities and applied clinical and sports sciences around the world.

Purpose In wheelchair tennis propulsion of the wheelchair is different for both hands, since the athlete has to hold a tennis racket in one hand. Differences in propulsion technique, i.e. forces and timing, have been found between propelling the wheelchair with and without a racket in the hand [1] . Optimizing the coupling of the hand with the racket to the rim is expected to lead to performance improvement Therefore, the purpose of this study was to explore different technical solutions for the interface between the hand, racket and the rim in order to optimize propulsion technique during wheelchair tennis when holding a racket. Methods A limited literature study was done on the interface between the hand, racket and the rim. Qualitative interviews were held with (sub)top Dutch tennis players and trainers to gain insight in their technique. Video analysis of training and tennis matches of (sub)top Dutch tennis players were made to acquire knowledge of the hand and racket positions. A list of requirements and several ideas were developed. Different prototypes of (a part of) a rim were 3d printed and tested in laboratory settings. Results The literature study showed an increase of effectivity of propulsive force by creating a larger contact area and increased friction; different textures and/or materials can create an increased friction. The video analysis showed a variety of racket positions between players and within players at different speeds. Five different design components and the connections between them were explored: push rim, wheel, the tire, the hand and the racket. Prototypes with a larger contact area and/or different material showed higher isometric peak forces. Conclusion This study shows different technical solutions for the interface between the hand, racket and the rim, which will improve propulsion technique during wheelchair tennis. The technical solutions are; different shape of the rim and/or using textures and/or materials with high friction coefficient on the rim and/or hand.

Objective The objective of this study was to investigate the effects of a low-intensity wheelchair training on propulsion technique in inactive people with long-term spinal cord injury.Design Participants in this multicenter nonblinded randomized controlled trial were inactive manual wheelchair users with spinal cord injury for at least 10 yrs (N = 29), allocated to exercise (n = 14) or no exercise. The 16-wk training consisted of wheelchair treadmill propulsion at 30%-40% heart rate reserve or equivalent in rate of perceived exertion, twice a week, 30 mins per session. Propulsion technique was assessed at baseline as well as after 8, 16, and 42 wks during two submaximal treadmill-exercise blocks using a measurement wheel attached to a participant's own wheelchair. Changes over time between the groups were analyzed using Mann-Whitney U tests on difference scores (P Results Data of 16 participants could be analyzed (exercise: n = 8). Significant differences between the exercise and control groups were only found in peak force after 8 wks (respective medians, -20 N vs. 1 N; P = 0.01; r(u) = 0.78).Conclusions Significant training effects on propulsion technique were not found in this group. Perhaps, substantial effects require a higher intensity or frequency. Investigating whether more effective and feasible interventions exist might help reduce the population's risk of upper-body joint damage during daily wheelchair propulsion.

Objective The objective of this study was to investigate the effects of a low-intensity wheelchair training on propulsion technique in inactive people with long-term spinal cord injury. Design Participants in this multicenter nonblinded randomized controlled trial were inactive manual wheelchair users with spinal cord injury for at least 10 yrs (N = 29), allocated to exercise (n = 14) or no exercise. The 16-wk training consisted of wheelchair treadmill propulsion at 30%-40% heart rate reserve or equivalent in rate of perceived exertion, twice a week, 30 mins per session. Propulsion technique was assessed at baseline as well as after 8, 16, and 42 wks during two submaximal treadmill-exercise blocks using a measurement wheel attached to a participant's own wheelchair. Changes over time between the groups were analyzed using Mann-Whitney U tests on difference scores (P

Recognizing the encouraging effect of challenging events, the HandbikeBattle (HBB) was created to promote exercise among wheelchair users. The purpose of this study was to reveal the effects on physical fitness and health outcomes of four-month handbike training under free-living conditions in preparation for the event.In this prospective cohort study, 59 relatively inexperienced handyclists participated in the HBB of 2013 or 2014. Incremental exercise tests were conducted, respiratory function was tested and anthropometrics were measured before and after the preparation period. Main outcome measures were peak power output (POpeak), peak oxygen uptake (VO2peak) and waist circumference, of which the changes were tested using repeated measures ANOVA. To detect possible determinants of changes in physical fitness, a linear regression analysis was conducted with personal characteristics, executed training volume and upper-extremity complaints during the training period as independent variables.POpeak, VO2peak and waist circumference improved significantly with 17%, 7% and 4.1%, respectively. None of the included variables were significant determinants for the changes in POpeak found as a result of the training.A challenging event such as the HBB provokes training regimes among participants of sufficient load to realize substantial improvements in physical fitness and health outcomes. Implications for Rehabilitation Due to the often impaired muscle function in the lower-limbs and an inactive lifestyle, wheelchair users generally show considerably lower levels of fitness compared to able-bodied individuals. This prospective cohort study showed that four months of handbike training under free-living conditions in preparation for this event resulted in substantial improvements in physical fitness and health outcomes in wheelchair users. The creation of a challenging event such as the HandbikeBattle as part of a follow-up rehabilitation practice can therefore be a useful tool to help wheelchair users initiate or keep training to improve their physical fitness and health.

OBJECTIVE: To describe the enabling factors and barriers experienced in the Wheelchair Expert Evaluation Laboratory - implementation (WHEEL-i) project, in which scientific knowledge, tools and associated systematic analyses of hand-rim wheelchair propulsion technique, user's wheelchair propulsion capacity, wheelchair-user interface, and wheelchair mechanics were implemented in 2 rehabilitation centres.DESIGN: Implementation project.PATIENTS: Spinal cord injury.METHODS: In this implementation project standardized tests were performed: wheelchair skills tests, 2 questionnaires, and a steady-state exercise test on a treadmill in which propulsion technique (forces and torques) and physical strain (oxygen uptake, heart rate and mechanical efficiency) were measured.RESULTS: Good interpretation of the test outcomes was the most important barrier. In order to discuss individual wheelchair performance results with patients and clinicians, reference data were developed, smallest detectable differences were calculated and software was developed to simultaneously show video recordings and force and torque signals.CONCLUSION: Based on pilot results, the greatest barrier to systematic monitoring of the individual wheelchair fitting and learning process in rehabilitation with, among others, instrumented measurement wheels, was interpretation of outcomes. For proper interpretation of individual outcomes, the availability of reference data, smallest detectable differences and visualization of outcomes is of utmost importance.

OBJECTIVE: To evaluate whether outcomes based on stopwatch time and power output (PO) over a 15m-overground wheelchair sprint test can be used to assess wheelchair-specific anaerobic work capacity, by studying their relationship with outcomes on a Wingate-based 30s-wheelchair ergometer sprint (WAnT).METHODS: Able-bodied persons (N=19, 10 men, aged 18-26 y) performed a 15m overground sprint test in an instrumented wheelchair and a WAnT. 15m-outcomes were based on stopwatch time (time and mean velocity over 15m) and on PO (primary outcome: highest mean unilateral PO over successive 5s-intervals (P5-15m)). WAnT-outcomes were mean unilateral PO over 30s and the highest mean unilateral PO over successive 5s-intervals. Correlation coefficients (Pearson's r) and coefficients of determination (R(2)) were calculated between 15m-sprint outcomes and WAnT-outcomes.RESULTS: Time over 15m (7.2s (± 1.0)) was weakly related to WAnT-outcomes (r=-0.61 and -0.60, R(2)=0.38 and 0.36, pCONCLUSIONS: It seems that outcomes based on stopwatch time over a 15m-overground sprint cannot be used to assess wheelchair-specific anaerobic work capacity, in contrast to an outcome based on PO (P5-15m). The 15m-sprint with an instrumented wheel can be implemented in rehabilitation practice and research settings when WAnT equipment is not available, although care is needed when interpreting P5-15m as an outcome of anaerobic work capacity given that it seems more skill-dependent than the WAnT.

Objective The objective of this study was to investigate the effects of a low-intensity wheelchair training on propulsion technique in inactive people with long-term spinal cord injury. Design Participants in this multicenter nonblinded randomized controlled trial were inactive manual wheelchair users with spinal cord injury for at least 10 yrs (N = 29), allocated to exercise (n = 14) or no exercise. The 16-wk training consisted of wheelchair treadmill propulsion at 30%-40% heart rate reserve or equivalent in rate of perceived exertion, twice a week, 30 mins per session. Propulsion technique was assessed at baseline as well as after 8, 16, and 42 wks during two submaximal treadmill-exercise blocks using a measurement wheel attached to a participant's own wheelchair. Changes over time between the groups were analyzed using Mann-Whitney U tests on difference scores (P

Objective. Investigation of the effect of visual feedback on effective hand rim wheelchair force production and the subsequent effect on gross mechanical efficiency.Design. Ten subjects in an experimental group and 10 subjects in a control group practised three weeks (3(.)wk(-1), i.e., a pre-test and 8 trials) on a computer-controlled wheelchair ergometer. Every trial consisted of two blocks of 4 min at 0.15 and 0.25 W. kg(-1) at 1.11 m(.)s(-1). On three trials an additional block at 0.40 W(.)kg(-1) was performed. The experimental group practised with and the control group practised without visual feedback on the effectiveness of force production.Background. In mechanical terms, the low gross mechanical efficiency of hand rim wheelchair propulsion may be the result of ineffective force production.Methods. During all trials oxygen uptake, power output, forces and torque on the hand rims were measured.Results. In comparison with the control group, the experimental group at trial 8 had a significantly more effective force production compared to the control group (90-97% vs. 79-83%, respectively), but showed a significantly lower mechanical efficiency (5.5-8.5% vs. 5.9-9.9%, respectively).Conclusion. Findings indicate that the most effective force production from a mechanical point of view is not necessarily the most efficient way - in terms of energy cost - from a biological point of view and that force direction is based on an optimization of cost and effect.

Objective: To investigate the influence of workload setting (speed at constant power, method to impose power) on the propulsion technique (i.e. force and timing characteristics) in handrim wheelchair propulsion. Method: Twelve able-bodied men participated in this study. External forces were measured during handrim wheelchair propulsion on a motor driven treadmill at different velocities and constant power output (to test the forced effect of speed) and at power outputs imposed by incline vs. pulley system (to test the effect of method to impose power). Outcome measures were the force and timing variables of the propulsion technique. Results: FEF and timing variables showed significant differences between the speed conditions when propelling at the same power output (p< 0.01). Push time was reduced while push angle increased. The method to impose power only showed slight differences in the timing variables, however not in the force variables. Conclusions: Researchers and clinicians must be aware of testing and evaluation conditions that may differently affect propulsion technique parameters despite an overall constant power output. © 2012 IPEM.

Purpose. To simulate the effect of low-intensity exercise in early rehabilitation, we investigated the effect of a 7-week low-intensity norm duration hand rim wheelchair training on the physical capacity in untrained able-bodied individuals.Method. Twenty-five able-bodied participants were randomly assigned to an experimental and control group: 10 participants exercised 7 weeks, three times a week at 30% heart rate reserve (HRR) for 30 min (experimental group). The control group consisted of 15 participants who did not receive training. Physical capacity (maximal isometric strength, sprint power, peak power output and peak oxygen uptake) and submaximal performance [heart rate (HR), oxygen uptake (VO(2)), mechanical efficiency (ME)] were assessed pre- and post-training. The levels of upper-body discomfort were determined with the use of a Local Perceived Discomfort scale.Results. Compared to the control group the experimental group significantly improved on sprint power (+31.2%), peak aerobic power output (+34%), submaximal HR, VO(2) and ME (+16.9%). The participants did not experience high levels of local discomfort in the upper body during the training.Conclusions. Low-intensity norm duration hand rim wheelchair training which significantly improved peak aerobic and sprint power output, efficiency and physical strain in able-bodied untrained individuals. Training at 30% HRR (3 x /week, 30 min/session) may be appropriate in untrained individuals, such as novice wheelchair users at the start of their rehabilitation, to prevent early fatigue and overuse and enhance motivation.

Purpose. To investigate the consequence on gross mechanical efficiency (GE), arm frequency and sub-maximal performance, of paced and unpaced practice during asynchronous hand-rim wheelchair propulsion.Methods. Twenty-five able-bodied participants performed five, 4-min exercise bouts at 1.7 m/s, at the freely chosen frequency (FCF) and four paced arm frequencies of 60, 80, 120 and 140% FCF. GE, arm frequency and measures of sub-maximal performance were determined. Participants were assigned to an unpaced (FCF, N = 9), paced (80% FCF, N = 8) or control (CON, N = 8) no practice group. The FCF and 80% FCF groups received 4-weeks (unpaced and paced, respectively) propulsion practice (three sessions center dot per wk, four 4 min/trials; 33-35 W) at 1.7 m/s on a wheelchair ergometer. Following practice, the pre-testing protocol was repeated.Results. Mean GE showed a relative increase in both experimental groups (21 and 17%; FCF and 80% FCF respectively; p = 0.001) compared to no change in CON (-1.5%). The FCF arm frequency decreased in both experimental groups (p = 0.001), with larger changes evident following FCF practice.Conclusion. Four weeks of unpaced or paced practice had a beneficial effect on GE. This improvement seems to be associated with a reduction in arm frequency.

Objective. Investigation of the effect of visual feedback on effective hand rim wheelchair force production and the subsequent effect on gross mechanical efficiency. Design. Ten subjects in an experimental group and 10 subjects in a control group practised three weeks (3(.)wk(-1), i.e., a pre-test and 8 trials) on a computer-controlled wheelchair ergometer. Every trial consisted of two blocks of 4 min at 0.15 and 0.25 W. kg(-1) at 1.11 m(.)s(-1). On three trials an additional block at 0.40 W(.)kg(-1) was performed. The experimental group practised with and the control group practised without visual feedback on the effectiveness of force production. Background. In mechanical terms, the low gross mechanical efficiency of hand rim wheelchair propulsion may be the result of ineffective force production. Methods. During all trials oxygen uptake, power output, forces and torque on the hand rims were measured. Results. In comparison with the control group, the experimental group at trial 8 had a significantly more effective force production compared to the control group (90-97% vs. 79-83%, respectively), but showed a significantly lower mechanical efficiency (5.5-8.5% vs. 5.9-9.9%, respectively). Conclusion. Findings indicate that the most effective force production from a mechanical point of view is not necessarily the most efficient way - in terms of energy cost - from a biological point of view and that force direction is based on an optimization of cost and effect.

Eight wheelchair sportsmen conducted eight wheelchair exercise tests on a treadmill. Two workload strategies were followed: strategy 1--increments in speed at a constant slope and strategy 2--increments in slope at constant velocity. Thus, data on cardio-respiratory and propulsion technique parameters were obtained on two identical series of 16 speed and slope combinations. Between each two identical speed and slope combinations of strategies 1 and 2, a different workload history is apparent. A four-factor analysis of variance with repeated measures on the factors "strategy" (workload history), "speed," and "slope" was applied (P less than 0.05). No "strategy" effect was seen in the cardio-respiratory parameters (gross mechanical efficiency, ventilation, oxygen consumption, and heart rate), work/cycle, and cycle time. Thus, within the experimental set-up, workload history did not affect the parameters studied and 3-min workload periods appeared sufficiently long for experienced wheelchair users to adapt to the requirements of a given speed and slope combination. Significant effects were found on "speed," "slope," and their interaction in all parameters tested. Moreover, a comparison of two equal levels of power output, but different speed and slope, led to a significantly higher efficiency, cycle time, and work per cycle for the "low speed and high slope" combination. Push time and recovery time appeared highly dependent on speed and slope, respectively. The findings indicate that propulsion technique and cardio-respiratory parameters should not merely be studied in relation to power output, but also with respect to its constituents, speed, and slope/resistance.