Three-Dimensional Kinematic Analysis and Physiologic Assessment of Racing Wheelchair Propulsion

1998 ◽  
Vol 15 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Thomas J. O’Connor ◽  
Rick N. Robertson ◽  
Rory A. Cooper
Keyword(s):  
Stepwise Regression ◽  
Three Dimensional ◽  
Maximum Speed ◽  
Wheelchair Propulsion ◽  
Wheelchair Athletes ◽  
Medium Speed ◽  
Preparatory Phase ◽  
Wrist Trajectory ◽  
Track Athletes ◽  
Hand Contact

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.

Three-Dimensional Kinematics of Wheelchair Propulsion across Racing Speeds

1995 ◽  
Vol 12 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Yong Tai Wang ◽  
Helga Deutsch ◽  
Martin Morse ◽  
Brad Hedrick ◽  
Tim Millikan
Keyword(s):  
Large Range ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Recovery Phase ◽  
Shoulder Abduction ◽  
Initial Contact ◽  
Wheelchair Propulsion ◽  
Kinematic Data ◽  
Initial Contact Angle ◽  
Wheelchair Athletes

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.

scholarly journals Comparisons of Three-Dimensional Pushrim Forces during Three Racing Speeds of Wheelchair Propulsion

2007 ◽  
Vol 39 (Supplement) ◽  
pp. S9
Author(s):  
Weerawat Limroongreungrat ◽  
Yong Tai Wang ◽  
Mark D. Geil ◽  
Jeffery T. Johnson ◽  
Ben F. Johnson ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Wheelchair Propulsion

The Relationship between Consistency of Propulsive Cycles and Maximum Angular Velocity during Wheelchair Racing

2008 ◽  
Vol 24 (3) ◽  
pp. 280-287 ◽  
Author(s):  
Yong “Tai” Wang ◽  
Konstantinos Dino Vrongistinos ◽  
Dali Xu
Keyword(s):  
Angular Velocity ◽  
Upper Limb ◽  
Wheelchair Propulsion ◽  
Upper Arm ◽  
Wheelchair Athletes ◽  
Angular Velocities ◽  
Limb Kinematics ◽  
Analysis System ◽  
The Right ◽  
The Relationship

The purposes of this study were to examine the consistency of wheelchair athletes’ upper-limb kinematics in consecutive propulsive cycles and to investigate the relationship between the maximum angular velocities of the upper arm and forearm and the consistency of the upper-limb kinematical pattern. Eleven elite international wheelchair racers propelled their own chairs on a roller while performing maximum speeds during wheelchair propulsion. A Qualisys motion analysis system was used to film the wheelchair propulsive cycles. Six reflective markers placed on the right shoulder, elbow, wrist joints, metacarpal, wheel axis, and wheel were automatically digitized. The deviations in cycle time, upper-arm and forearm angles, and angular velocities among these propulsive cycles were analyzed. The results demonstrated that in the consecutive cycles of wheelchair propulsion the increased maximum angular velocity may lead to increased variability in the upper-limb angular kinematics. It is speculated that this increased variability may be important for the distribution of load on different upper-extremity muscles to avoid the fatigue during wheelchair racing.

scholarly journals Finite life fatigue design of spiral springs of dual-mass flywheels: Analytical estimation and experimental results

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401877847 ◽  
Author(s):  
Daniela Maffiodo ◽  
Raffaella Sesana ◽  
Dino Paolucci ◽  
Sabrina Bertaggia
Keyword(s):  
Finite Element ◽  
Optimization Design ◽  
Three Dimensional ◽  
Element Model ◽  
Installation Space ◽  
Maximum Speed ◽  
Estimation Model ◽  
Element Analysis ◽  
Life Estimation ◽  
Three Dimensional Finite Element

A procedure to design the spiral springs finite life for dual-mass flywheels is presented. Due to design constraints, installation space, production processes, stiffness requirement, maximum torque, and maximum speed, these components are dimensioned for finite life. Two- and three-dimensional finite element model static structural analysis was performed to obtain the stress distribution, deformed shape, and to validate optimization design. The fatigue analysis was performed both experimentally and by means of a component life estimation model. An experimental duty cycle was applied. Finite element analysis and experimental analysis agree in pointing out the location and the value of maximum stresses and the shape of deformation. Vehicle tests highlight premature spiral springs’ failures, which do not agree with life estimation. The examination of the fracture showed that fretting and wear, along with fatigue phenomena, are the causes of premature failures. A dedicated component life estimation model is required, taking into account of wear and loading history.

scholarly journals In vivo two-photon excited fluorescence microscopy reveals cardiac- and respiration-dependent pulsatile blood flow in cortical blood vessels in mice

2012 ◽  
Vol 302 (7) ◽  
pp. H1367-H1377 ◽  
Author(s):  
Thom P. Santisakultarm ◽  
Nathan R. Cornelius ◽  
Nozomi Nishimura ◽  
Andrew I. Schafer ◽  
Richard T. Silver ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fluorescence Microscopy ◽  
Capillary Tube ◽  
Three Dimensional ◽  
Vessel Diameter ◽  
Vascular Network ◽  
Maximum Speed ◽  
Flow Profile ◽  
Two Photon ◽  
Surface Vessels

Subtle alterations in cerebral blood flow can impact the health and function of brain cells and are linked to cognitive decline and dementia. To understand hemodynamics in the three-dimensional vascular network of the cerebral cortex, we applied two-photon excited fluorescence microscopy to measure the motion of red blood cells (RBCs) in individual microvessels throughout the vascular hierarchy in anesthetized mice. To resolve heartbeat- and respiration-dependent flow dynamics, we simultaneously recorded the electrocardiogram and respiratory waveform. We found that centerline RBC speed decreased with decreasing vessel diameter in arterioles, slowed further through the capillary bed, and then increased with increasing vessel diameter in venules. RBC flow was pulsatile in nearly all cortical vessels, including capillaries and venules. Heartbeat-induced speed modulation decreased through the vascular network, while the delay between heartbeat and the time of maximum speed increased. Capillary tube hematocrit was 0.21 and did not vary with centerline RBC speed or topological position. Spatial RBC flow profiles in surface vessels were blunted compared with a parabola and could be measured at vascular junctions. Finally, we observed a transient decrease in RBC speed in surface vessels before inspiration. In conclusion, we developed an approach to study detailed characteristics of RBC flow in the three-dimensional cortical vasculature, including quantification of fluctuations in centerline RBC speed due to cardiac and respiratory rhythms and flow profile measurements. These methods and the quantitative data on basal cerebral hemodynamics open the door to studies of the normal and diseased-state cerebral microcirculation.

Research of the Installation Angle of New Rotor Impact Plate Based on EDEM

2011 ◽  
Vol 80-81 ◽  
pp. 1133-1137
Author(s):  
De Rong Duan ◽  
Fang Zhao ◽  
Song Wang ◽  
Xian Xin Chen
Keyword(s):  
Dynamic Simulation ◽  
Impact Force ◽  
Three Dimensional ◽  
Substantial Effect ◽  
Maximum Speed ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Installation Angle ◽  
Impact Plate ◽  
The Impact

The three-dimensional model of new rotor was imported into EDEM for dynamic simulation, the maximum speed and force were analysied in the EDEM,indicating that the material along the deterministic trajectory collide with the impact plate for second acceleration after the first acceleration in new rotor, the velocity after second acceleration was 2.3 times than the first acceleration.The impact force and angle did not substantial effect on the second acceleration by comprehensive comparing,the 69m/s speed and less impact force were generated in the new rotor with 2° impact plate installation angle.

Parallel 3-D pseudospectral simulation of seismic wave propagation

Geophysics ◽  
1998 ◽  
Vol 63 (1) ◽  
pp. 279-288 ◽  
Author(s):  
Takashi Furumura ◽  
B. L. N. Kennett ◽  
Hiroshi Takenaka
Keyword(s):  
Wave Propagation ◽  
Parallel Algorithm ◽  
Three Dimensional ◽  
Seismic Wave Propagation ◽  
Parallel Computer ◽  
Maximum Speed ◽  
Computational Domain ◽  
Concurrent Use ◽  
Speed Up ◽  
Digital Equipment

Three‐dimensional pseudospectral modeling for a realistic scale problem is still computationally very intensive, even when using current powerful computers. To overcome this, we have developed a parallel pseudospectral code for calculating the 3-D wavefield by concurrent use of a number of processors. The parallel algorithm is based on a partition of the computational domain, where the field quantities are distributed over a number of processors and the calculation is concurrently done in each subdomain with interprocessor communications. Experimental performance tests using three different styles of parallel computers achieved a fairly good speed up compared with conventional computation on a single processor: maximum speed‐up rate of 26 using 32 processors of a Thinking Machine CM-5 parallel computer, 1.6 using a Digital Equipment DEC‐Alpha two‐CPU workstation, and 4.6 using a cluster of eight Sun Microsystems SPARC-Station 10 (SPARC-10) workstations connected by an Ethernet. The result of this test agrees well with the performance theoretically predicted for each system. To demonstrate the feasibility of our parallel algorithm, we show three examples: 3-D acoustic and elastic modeling of fault‐zone trapped waves and the calculation of elastic wave propagation in a 3-D syncline model.

The Relationship between Three-Dimensional Wheelchair Propulsion Techniques and Pushing Economy

1998 ◽  
Vol 14 (4) ◽  
pp. 412-427 ◽  
Author(s):  
Victoria L. Goosey ◽  
Ian G. Campbell ◽  
Neil E. Fowler
Keyword(s):  
Individual Differences ◽  
Three Dimensional ◽  
Mechanical Efficiency ◽  
Physiological Data ◽  
Wheelchair Propulsion ◽  
Key Variables ◽  
The Relationship

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.

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