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Mary M. Rodgers, Srinivas Tummarakota and Junghsen Lieh

A three-dimensional (3-D) inverse dynamic model of wheelchair propulsion was developed using the Newton-Euler method based on body coordinate systems. With this model, the arm was assumed to be three rigid segments (hand, forearm, and upper arm) connected by the wrist, elbow, and shoulder joints. A symbolic method was adopted to generate the equations of motion. The model was used to compute the joint forces and moments based on the inputs obtained from a 3-D motion analysis system, which included an instrumented wheelchair, video cameras, and a data acquisition system. The linear displacements of markers placed on the joints were measured and differentiated to obtain their velocities and accelerations. Three-dimensional contact forces and moments from hand to handrim were measured and used to calculate joint forces and moments of the segments.

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Marisa Maia Leonardi-Figueiredo, Mariana Angélica de Souza, Elisangela Aparecida da Silva Lizzi, Luciano Fonseca Lemos de Oliveira, Julio Cesar Crescencio, Pedro Vellosa Schwartzmann, Lourenço Gallo Jr and Ana Claudia Mattiello-Sverzut

in the lower limbs. A recent systematic review evaluated the exercise training programs to improve hand-rim wheelchair propulsion capacity. The study showed that wheelchair propulsion exercise is more appropriate than arm cranking because it improves the mechanical efficiency of individuals using

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Rory A. Cooper

This paper analyzes several factors that affect racing wheelchair propulsion. The basis of this paper results from experiments performed using five individuals who had traumatic spinal cord injuries. These individuals were asked to simulate sprinting and distance running while on a roller system equipped with an analog tachometer. The results of this study show the time spent in propulsion and recovery as has not been shown previously; the use of analog tachometer yields new information about racing wheelchair propulsion. The points of contact for each athlete’s strokes were recorded using a video camera. The point of contact with the push-ring and the application of force appear to coincide. In addition, some subjects displayed periods of constant velocity during the propulsion cycle. The mean percent propulsion times for this study were 66, 34, and 30% for the first stroke, the sprint test, and the distance test, respectively. The mean percent recovery times were 34, 66, and 70% for the first stroke, the sprint test, and the distance test, respectively.

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Yong Tai Wang, Helga Deutsch, Martin Morse, Brad Hedrick and Tim Millikan

Three-dimensional (3-D) kinematic features of wheelchair propulsion across four selected speeds were investigated based on 10 skilled male wheelchair athletes. Kinematic data were collected through 3-D cinematography with a mirror. The results demonstrated that as the speed increased, the drive phase was performed faster while the range of the push-angle remained constant. More trunk forward lean motion resulted in a large initial contact angle in front of the top dead center of the pushrim. Recovery involved a large range of vertical motion in terms of shoulder abduction and hyperextension in order to increase the distance over which a greater velocity could be developed. To maximize wheelchair racing speed, it was critical to obtain the maximal shoulder and elbow velocities at initial contact of the drive phase and the maximal hand velocity at the end of the recovery phase.

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Alicia M. Koontz, Lynn A. Worobey, Ian M. Rice, Jennifer L. Collinger and Michael L. Boninger

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.

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Thomas J. O’Connor, Rick N. Robertson and Rory A. Cooper

Three-dimensional kinematic variables and their relationship to the physiology of racing wheelchair propulsion were studied. Six male wheelchair athletes performed two trials (medium and maximum speed) of 3 min each. VO2, VO2/kg, VE, and HR were measured. Results showed that at medium speed, wrist velocity on hand contact was significantly correlated with VO2/kg. At maximum speed, elbow velocity during preparatory phase was significantly correlated with VO2. Stepwise regression showed wrist trajectory angle and elbow velocity during preparatory phase were significantly correlated with VO2/kg. Results indicate that kinematic variables recorded prior to and on hand contact with the pushrim are significant variables in developing a more efficient racing wheelchair propulsion technique. Results of this study indicate a need to educate coaches of wheelchair track athletes concerning the best racing wheelchair propulsion technique.

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Ursina Arnet, Stefan van Drongelen, DirkJan Veeger and Lucas H. V. van der Woude

The aim of the study was to evaluate the external applied forces, the effectiveness of force application and the net shoulder moments of handcycling in comparison with handrim wheelchair propulsion at different inclines. Ten able-bodied men performed standardized exercises on a treadmill at inclines of 1%, 2.5% and 4% with an instrumented handbike and wheelchair that measured three-dimensional propulsion forces. The results showed that during handcycling significantly lower mean forces were applied at inclines of 2.5% (P < .001) and 4% (P < .001) and significantly lower peak forces were applied at all inclines (1%: P = .014, 2.5% and 4%: P < .001). At the 2.5% incline, where power output was the same for both devices, total forces (mean over trial) of 22.8 N and 27.5 N and peak forces of 40.1 N and 106.9 N were measured for handbike and wheelchair propulsion. The force effectiveness did not differ between the devices (P = .757); however, the effectiveness did increase with higher inclines during handcycling whereas it stayed constant over all inclines for wheelchair propulsion. The resulting peak net shoulder moments were lower for handcycling compared with wheelchair propulsion at all inclines (P < .001). These results confirm the assumption that handcycling is physically less straining.

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Beatriz M. Crespo-Ruiz, Antonio J. Del Ama-Espinosa and ángel M. Gil-Agudo

The objective was to conduct a methodological pilot study to analyze wheelchair propulsion upper limb kinematics in standard competitive play considering the functional classification of each athlete. Ten basketball players with a functional classification ranging from 1 to 4 were included in the study. Four camcorders (Kinescan-IBV) and a treadmill for wheelchairs were used. Temporal parameters were analyzed and the upper limb kinematics was obtained using ISB recommendations. The value of the temporal parameters such as push phase duration, the ratio of push phase/recovery phase, contact, and propulsion angle seems to reduce as the functional classification increases. A methodological protocol has been developed that allows the analysis of kinematic characteristics of wheelchair propulsion in basketball players taking into account their functional classification.

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Scott A. Conger, Stacy N. Scott, Eugene C. Fitzhugh, Dixie L. Thompson and David R. Bassett

Background:

It is unknown if activity monitors can detect the increased energy expenditure (EE) of wheelchair propulsion at different speeds or on different surfaces.

Methods:

Individuals who used manual wheelchairs (n = 14) performed 5 wheeling activities: on a level surface at 3 speeds, on a rubberized track at 1 fixed speed and on a sidewalk course at a self-selected speed. EE was measured using a portable indirect calorimetry system and estimated by an Actical (AC) worn on the wrist and a SenseWear (SW) activity monitor worn on the upper arm. Repeated-measures ANOVA was used to compare measured EE to the estimates from the standard AC prediction equation and SW using 2 different equations.

Results:

Repeated-measures ANOVA demonstrated a significant main effect between measured EE and estimated EE. There were no differences between the criterion method and the AC across the 5 activities. The SW overestimated EE when wheeling at 3 speeds on a level surface, and during sidewalk wheeling. The wheelchair-specific SW equation improved the EE prediction during low intensity activities, but error progressively increased during higher intensity activities.

Conclusions:

During manual wheelchair propulsion, the wrist-mounted AC provided valid estimates of EE, whereas the SW tended to overestimate EE.

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Victoria L. Goosey, Ian G. Campbell and Neil E. Fowler

Three-dimensional kinematic and physiological data were obtained from 18 wheelchair racers, to allow the relationship between pushing economy and kinematic variables at 4.70 m · s−1 (n = 18) and 6.58 m · s−1 (n = 12) to be examined. Large inter individual differences in wheelchair propulsion styles were present, which made it difficult to identify variables that were associated with pushing economy and indeed to distinguish key variables that were characteristic of an economical wheelchair racer. Furthermore, those variables associated with economy proved inconsistent across the two speeds. However, at both speeds a higher mechanical efficiency and lower push rate were associated with better economy (p < .05). It was also found that the timing parameters were important. In this respect most athletes tended to push through a similar push angle; however, push rate differed between individuals, suggesting that the magnitude and direction of the hand-rim forces may be important for determining economy of propulsion.