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David S. Haydon, Ross A. Pinder, Paul N. Grimshaw and William S.P. Robertson

Wheelchair-propulsion kinematics have been investigated across a range of activities including wheelchair basketball, 1 wheelchair racing, 2 and daily living. 3 Variables such as contact and release angles, as well as stroke and recovery times, have been used to assess variations across athlete

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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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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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I-Chieh Lee, Yeou-Teh Liu and Karl M. Newell

We investigated the coordination of balance and propulsion processes in learning to ride a unicycle through a principal component analysis (PCA) of the nature and number of functional degrees of freedom (DOF) in the movement coordination patterns. Six participants practiced unicycle riding on an indoor track for 28 sessions over separate days. The movement time and performance outcomes were recorded for each trial and body segment kinematics were collected from the first and every succeeding 4th session. The first appearance of no-hand-support performance varied across participants from the 5th practice session to the 22nd session. The PCA showed that initially in practice the 39 kinematic time series could be represented by 6–9 components that were reduced over practice to 4–7 components. The loadings of the PCA that reflected balance and propulsion processes became more coupled as a function of successfully riding the unicycle. The findings support the proposition that learning to ride the unicycle is a process of making the system more controllable by coordinating balance and propulsion while mastering the redundant DOF.

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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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Andrew A. Dingley, David B. Pyne and Brendan Burkett

Purpose:

To characterize relationships between propulsion, anthropometry, and performance in Paralympic swimming.

Methods:

A cross-sectional study of swimmers (13 male, 15 female) age 20.5 ± 4.4 y was conducted. Subject locomotor categorizations were no physical disability (n = 8, classes S13–S14) and low-severity (n = 11, classes S9–S10) or midseverity disability (n = 9, classes S6–S8). Full anthropometric profiles estimated muscle mass and body fat, a bilateral swim-bench ergometer quantified upper-body power production, and 100-m time trials quantified swimming performance.

Results:

Correlations between ergometer mean power and swimming performance increased with degree of physical disability (low-severity male r = .65, ±0.56, and female r = .68, ±0.64; midseverity, r = .87, ±0.41, and r = .79, ±0.75). The female midseverity group showed nearperfect (positive) relationships for taller swimmers’ (with a greater muscle mass and longer arm span) swimming faster, while for female no- and low-severity-disability groups, greater muscle mass was associated with slower velocity (r = .78, ±0.43, and r = .65, ±0.66). This was supported with lighter females (with less frontal surface area) in the low-severity group being faster (r = .94, ±0.24). In a gender contrast, low-severity males with less muscle mass (r = -.64, ±0.56), high skinfolds (r = .78, ±0.43), a longer arm span (r = .58, ±0.60) or smaller frontal surface area (r = -.93, ±0.19) were detrimental to swimming-velocity production.

Conclusion:

Low-severity male and midseverity female Paralympic swimmers should be encouraged to develop muscle mass and upper-body power to enhance swimming performance. The generalized anthropometric measures appear to be a secondary consideration for coaches.

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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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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.