Resistive and propulsive forces in wheelchair racing: a brief review

Wheelchair racing is one of the most important sports in the Paralympics. The detailed analysis of all parameters is of great importance to achieve sporting excellence in this modality. In wheelchair racing, resistive and propulsive forces determine the movement of the athlete-wheelchair system. Most of propulsive forces are generated by the strength of individuals. As a result, strength levels play an important role in propelling the athlete-wheelchair system. Thus, the main objective of this study is to provide a set of methodologies to assess propulsive and resistive forces. The manuscript presents different methods and procedures, based on previous studies, that can be used for wheelchair racing athletes. Resistive forces in wheelchair racing can be evaluated by analytical procedures, experimental tests, and numerical simulations. Moreover, the strength of athletes' upper limbs to generate propulsion in wheelchair races can be assessed by dynamometry, one-repetition maximum, and medicine ball throw test. It may be that the tests presented may be useful to predict the strength and endurance of athletes' upper limbs. However, this competitive sport still presents a considerable gap in the Paralympics research. Currently, in Paralympic sport, evidence-based methodologies are lacking, making it an issue for athletes, coaches and researchers to support their work on scientific evidences.This research is supported by the Portuguese Foundation for Science and Technology, I.P. (project UIDB04045/2020) and The APC. It has been funded by the Research Center in Sports Health and Human Development, CovilhA, Portugal.info:eu-repo/semantics/publishedVersio

BIOMECHANICS OF WHEELCHAIR RACING

An additional assistive device - such as a wheelchair or a prosthesis often forms an integral part of the disabled athlete and a functional prerequisite for mobility and sports participation. The use of such a tool in high performance sports situations sets typical demands to the performance capacity of the athlete. but also to the methods end techniques of biomechanical research. Apart from environmental f a e m research into the optimization of performance in wheelchair racing will have to focus on three areas of interest Firstly, the dynamics and design of wheelchairs should conform to the laws of (vehicle) mechanics. Rolling resistance, air drag and internal friction must be minimized, since these forces determine the e x m a 1 power output which the human engine will have to deliver at a certain speed. 'Lightweight' and 'high tech' an the keywords of contemporary racing wheelchairs. Their design is task-directed and - within this framework - tuned to the individual demands of the athlete. Secondly. work capacity and propulsion technique an major determinants in the performance of the human engine. Performance is primarily dependent upon the functional and training status of the upper body of the athlete. Understanding the detailed functional role of the upper body in wheelchair track performance requires a combined biomechanical and physiological study of arm work under realistic experimental conditions and in different groups of subjects. Thirdly, performance of the wheelchair-user combination is influenced by the interfacing between the wheelchair and the athlete. Development of fitting criteria with respect to geometry and mechanics of the wheelchair requires a combined biomechanical and physiological approach too. Wheelchair propulsion is frequently studied on a motor driven treadmill. 'Three-dimensional kinematics and electromyography arc combined in conjunction with overall physiology and prove to lead to a valuable description of same biomechanical aspects of wheeled mobility. To enable a more detailed biodynamic analysis of wheelchair propulsion a computer-controlled wheelchair ergo meter was designed. Through simulation of wheelchair propulsion force characteristics in all interfacing units of the wheelchair-user combination an studied: the seat. backrest and the rims. Thus torque production. efficacy of force generation and the net torque and power production over the different joints are studied under (sub-)maximal performance conditions and in conjunction with different aspects of the wheelchair-user interface. Within this framework special attention is dedicated to the functional anatomy and biomechanics of the shoulder mechanism, which is crucial in power production. Modelling of the shoulder mechanism - based on detailed dissection studies - will help clarify its role in propulsion technique and will help specify wheelchair fitting guidelines. This integrated anatomical. biomechanical and physiological approach may eventually help explain the human potential and limitations in arm work and the mechanisms which lead to overuse injuries in the arm-shoulder complex

Aerodynamics of a wheelchair sprinter racing at the 100m world record pace by CFD

The aim of this study was to analyze aerodynamics in a racing position of a wheelchair-racing sprinter, at the world record speed. The athlete and wheelchair were scanned at the beginning of the propulsive phase position (hands near the handrims at 12h) for the 3D model acquisition. Numerical simulation was run on Fluent, having as output the pressure, viscosity and total drag force, and respective coefficients of drag at the world record speed in T-52 category. Total drag was 7.56N and coefficient of drag was 1.65. This work helped on getting a deeper insight about the aerodynamic profile of a wheelchair-racing athlete, at a 100m world record speed.info:eu-repo/semantics/publishedVersio

MEASURING RACING WHEELCHAIR SPATIOTEMPORAL VARIABLES USING A PHONE CAMERA: A PRELIMINARY CONCURRENT VALIDITY STUDY

The purpose of this study was to assess the measurement agreement between a low-cost system (phone camera) and a reference optoelectronic system, to measure spatiotemporal variables that may be related to wheelchair racing performance: acceleration phase time, push time, backswing time, and maximal elbow height. Three regular wheelchair racers propelled at maximal velocity on a training roller. The temporal variables had a low disagreement between both systems (bias ± 1.96 std of less than 0.01 s ± 0.02 s), while for the maximal elbow height, a higher disagreement of 0.020 m ± 0.038 m was observed. Future improvements are required especially to measure the maximal elbow height. This method may have long term benefits both for the athletes and research, by including more wheelchair racing athletes in future biomechanics studies

Partial contribution of rolling friction and drag force to total resistance of an elite wheelchair athlete

In wheelchair racing, the main sources to loose energy are the rolling friction and the drag force. The aim of this research was to model the partial contribution of rolling friction and drag force to total resistance of an elite wheelchair athlete.info:eu-repo/semantics/publishedVersio

Aerodynamic drag on helmet use in wheelchair racing

Nas provas de velocidade em cadeira de rodas os atletas paralímpicos recorrem à utilização de capacetesIn wheelchair racing sprinting events, Paralympics use helmets. During the strokes, athletes tend to oscillate the head with helmet use looking down and forward in only one stroke.info:eu-repo/semantics/publishedVersio