Wheelchair Racing Research Articles

Locomotor-Respiratory Coupling in Wheelchair Racing Athletes: A Pilot Study.

Purpose: In wheelchair racing, respiratory muscles of the rib cage are concomitantly involved in non-ventilatory functions during wheelchair propulsion. However, the relationship between locomotor-respiratory coupling (LRC: the ratio between push and breathing frequency), respiratory parameters and work efficiency is unknown. Therefore, the aim of the present study was to investigate the LRC in wheelchair racers over different race distances.Methods: Eight trained and experienced wheelchair racers completed three time-trials over the distances of 400, 800, and 5000 m on a training roller in randomized order. During the time trials, ventilatory and gas exchange variables as well as push frequency were continuously registered to determine possible LRC strategies.Results: Four different coupling ratios were identified, namely 1:1; 2:1, 3:1 as well as a 1:1/2:1 alternating type, respectively. The 2:1 coupling was the most dominant type. The 1:1/2:1 alternating coupling type was found predominantly during the 400 m time-trial. Longer race distances tended to result in an increased coupling ratio (e.g., from 1:1 toward 2:1), and an increase in coupling ratio toward a more efficient respiration was found over the 5000 m distance. A significant correlation (r = 0.80, p < 0.05) between respiratory frequency and the respiratory equivalent for oxygen was found for the 400 m and the 800 m time-trials.Conclusions: These findings suggest that a higher coupling ratio indicates enhanced breathing work efficiency with a concomitant deeper and slower respiration during wheelchair racing. Thus, the selection of an appropriate LRC strategy may help to optimize wheelchair racing performance.

車いすマラソンのシミュレーションモデル構築

In order to improve the performance in wheelchair racing, it is important for players to use the optimum wheelchair and to propel it in the optimum manner. However, only trial and error is conducted in the present training situation to find them. In order to consider the whole dynamics of player and wheelchair, a simulation model was developed in the present study. In this model, forces were given on joints of upper body, as well as between hand and handrim. Also, the forces between tyres and road were calculated by the magic formula. As a result, the experimental situation was successfully reproduced in this model, and the torque acting on joints were investigated. The developed model enabled to evaluate wheelchair and propelling style.

陸上競技用車いすのためのセンサーホイールの開発とそれを活用した駆動力計測

陸上競技用車いすのためのセンサーホイールの開発とそれを活用した駆動力計測

The Influence of Glove Type on Simulated Wheelchair Racing Propulsion: A Pilot Study

Our purpose was to examine the influence of glove type on kinetic and spatiotemporal parameters at the handrim in elite wheelchair racers. Elite wheelchair racers (n=9) propelled on a dynamometer in their own racing chairs with a force and moment sensing wheel attached. Racers propelled at 3 steady state speeds (5.36, 6.26 & 7.60 m/s) and performed one maximal effort sprint with 2 different glove types (soft & solid). Peak resultant force, peak torque, impulse, contact angle, braking torque, push time, velocity, and stroke frequency were recorded for steady state and sprint conditions. Multiple nonparametric Wilcoxon matched pair's tests were used to detect differences between glove types, while effect sizes were calculated based on Cohen's d. During steady state trials, racers propelled faster, using more strokes and larger contact angle, while applying less impulse with solid gloves compared to soft gloves. During the sprint condition, racers achieved greater top end velocities, applying larger peak force, with less braking torque with solid gloves compared to soft gloves. Use of solid gloves may provide some performance benefits to wheelchair racers during steady state and top end velocity conditions.

Testing for boosting at the Paralympic games: policies, results and future directions

Background‘Boosting’ is defined as the intentional induction of autonomic dysreflexia (AD) by athletes with a spinal cord injury (SCI) at or above the level of T6 for the purpose of...

Wheelchair racing: chair set-up, conventional seating position, kneeling position, para backhand technique, injury prevention

Wheelchair racing: chair set-up, conventional seating position, kneeling position, para backhand technique, injury prevention

The Human Engineering Analysis of the Racing Wheelchair

In order to improve the human engineering properties for the racing wheelchair, using the CATIA Human Engineering Analysis module, this paper established the human body 3-D model, analyzed the eligibility of the hold and the extend for the racing wheelchair, analyzed and evaluated the comfort of three typical sports postures of human body. The general evaluation results accorded with the human body kinematic theory, and the upper limb comfort gradually became better, in a movement cycle of the upper limbs driving the wheelchair.

Trunk Strength Effect on Track Wheelchair Start

The T54 wheelchair racing class comprises athletes with normal arm muscle strength and trunk strength ranging from partial to normal. Paralympic sports classes should comprise athletes who have impairments that cause a comparable degree of activity limitation. On the basis of this criterion, the purpose of this study was to determine whether the T54 class is valid by assessing the strength of association between trunk strength and wheelchair acceleration. Participants were 10 male and 3 female international wheelchair track athletes with normal arm strength. Six were clinically assessed as having normal trunk strength, and seven had impaired trunk strength. Measures included isometric arm and trunk strength and distance covered at 1, 2, and 3 s in an explosive start from standstill on a regulation track, as well as on a custom-built ergometer with four times normal rolling resistance. No significant differences were observed between male athletes with and without full trunk strength in distance covered after 1, 2, and 3 s. Correlations between isometric trunk strength and wheelchair track acceleration were nonsignificant and low (0.27-0.32), accounting for only 7%-10% of variance in performance. Correlations between trunk strength and distance pushed under high resistance were also nonsignificant, although values were almost double (r = 0.41-0.54), accounting for 18%-28% of the variance in performance. These results provide evidence that impairment of trunk strength has minimal effect on wheelchair acceleration and indicate the T54 class is valid. Results do not infer that athletes with no trunk strength should compete with those who have partial or full trunk strength.

Correlation of heart rate at lactate minimum and maximal lactate steady state in wheelchair-racing athletes

Prospective, experimental study. To investigate whether the heart rate (HR) at lactate minimum (LMHR)determined by means of a HR-guided lactate minimum test (LMT) corresponds to the HR at maximal lactate steady state (MLSS) in wheelchair-racing athletes. Institute of Sports Medicine. Eight well-trained wheelchair-racing athletes (mean age: 33±12 years; height: 169±12 cm; body mass: 59±11 kg; VO(2peak): 2.76±0.73 l min(-1)) completed a HR-guided LMT on a treadmill in their own racing wheelchair. Subsequently, exercise intensity at MLSS and corresponding HR were determined by means of several endurance tests on different days. All measured parameters (HR, speed, blood lactate, oxygen consumption and rating of perceived exertion) revealed significantly higher values at MLSS compared with values at lactate minimum (LM). However, there were highly significant correlations (r=0.914, P=0.002) between LMHR and HR at MLSS (163±6 versus 172±7 b.p.m.) as well as for speed (r=0.935, P=0.001) and blood lactate (r=0.944, P<0.001) at LM versus MLSS. The correlation for oxygen consumption (r=0.798, P=0.018) at LM versus MLSS was lower yet significant. There exists a close relationship between LMHR and HR at MLSS in wheelchair racing. This allows the prediction of MLSS based on a single exercise test in this special group of athletes. For practical use during daily training, routine HR at MLSS can be assumed to be 8-9 b.p.m. above the LMHRin wheelchair-racing athletes.

Kinematic Features of Wheelchair Propulsion of Elite Chinese National Wheelchair Racers

PURPOSE: This study was to investigate kinematic features of wheelchair propulsion among elite Chinese wheelchair racers during Training Camp of the 2008 Paralympic Games. METHODS: Seven wheelchair racers in Chinese National Paralympic Team (2 females, 5 males, age 25±4.4, body mass 60.3±4.6kg, training year 9.1±2.4) were filmed from the sagittal and front views by a MaxTraq motion analysis system at 60 Hz while they propelled their own racing wheelchairs at maximal speeds on a training roller. Seven reflective markers were placed on the right ear, acromion, lateral epicondyle of humerus, styloid process of Ulna, 3rd metacarpophalangeal joint, wheel axis and pushim. Film data were digitized and smoothed before the joint angles, and angular and linear velocities of the upper extremity were calculated. RESULTS: The results showed the drive phase time (DT), recovery time (RT) and cycle time (CT) were 0.095±0.013, 0.252±0.103 and 0.347±0.114 seconds, respectively. The hand contact angle, release angle and range on the pushrim were 44.2°±2.9, 207.8°±20.2 and 163.6° ±21.8, respectively. The maximal shoulder, elbow and wrist joint angles were 24.1°±25.2, 142.4°±32.2 and 158.7°±14.2, respectively in the drive phase and 66.6° ±27.1, 157.1° ±27.2 and 194.2°±15.3 in the recovery phase. The maximal angular velocities at the shoulder, elbow and wrist joints were 189.5°/s±98.2, 255°/s±165.4 and 573.6°/s±262.4 in the drive phase and 506.3±210.5, 465.6±210.1 and 590.8±273.6°/s in the recovery phase. The pattern recognition demonstrated that the Chinese wheelchair racers used the circular pattern with high upper arm elevation in the recovery phase. CONCLUSION: The Chinese national wheelchair racers had faster CT (0.347s) with comparison to other national wheelchair racers (approximately 0.500s). With the circular stroke pattern, the Chinese wheelchair racers sequentially increased their angular velocities from the shoulder to elbow, then to wrist in the drive phase. The greater upper arm elevation at the end of recovery phase may facilitate the racing speed production in the drive phase.

Supporting the paralympic athlete: focus on wheeled sports

The complexity of wheelchair sports provides the scientist with a unique challenge. There are two major components that contribute towards ‘wheeled sports’ performance: the athlete and the chair. It is the interaction of these two components that enable wheelchair propulsion and the sporting movements required within a given sport. This article will describe three discrete case studies on how sport scientists have worked with Great Britain coaches and practitioners to help optimise training leading to a major competition through evidence base practise. A fourth area will describe on-going work designed to address the optimisation of wheelchair configurations for wheelchair court sports. It will focus on four sports: wheelchair racing, wheelchair tennis, wheelchair basketball and wheelchair rugby. The first topic will discuss the concept of pushing economy and mechanical efficiency of wheelchair propulsion. The second topic will show how technology assists the coaching process. The third topic will illustrate the concept of sports classification, and show how training volume ‘in terms of basketball shooting’ may need to be individually assigned and finally future research within wheelchair team sports and chair configurations will be examined.

Boosting in athletes with high-level spinal cord injury: knowledge, incidence and attitudes of athletes in paralympic sport

Autonomic dysreflexia (AD) is unique to individuals with spinal injuries (SCI) at T6 or above and can be voluntarily induced. Although AD improves wheelchair racing performance in some athletes, it also elicits exaggerated blood pressure, which could be dangerous. The International Paralympic Committee considers AD doping and banned its use. Purpose. The purpose of this study is to evaluate AD knowledge, incidence and attitudes (KIA) of Paralympians with SCI. Methods. An existing questionnaire was modified to include questions of AD KIA, validated by three experts and piloted with a small sample. It was administered on-line, mailed to members of a scientific network and distributed during the Beijing Paralympic Games. Fisher Exact test was used to evaluate differences across gender, injury and education. Results. Of 99 participants, 54.5% had previously heard of AD while 39.4% were unaware; 16.7%, all males, had used AD to enhance performance. Participants reported that AD was (1) useful for middle (78.6%) and long distance (71.4%), marathon (64.3%) and wheelchair rugby (64.3%); (2) somewhat dangerous (48.9%), dangerous (21.3%) or very dangerous (25.5%) to health. Results were not influenced by age, injury level or injury duration. Conclusions. Findings indicate the need for educational programmes directed towards enhancing the AD knowledge of rehabilitation professionals, coaches and trainers working with SCI individuals.

Influence of mass on the speed of wheelchair racing

Reducing the mass of a racing wheelchair improves the winning time even for relatively small mass reductions over short distances (100 m). In this study, the improvement of speed and winning time on mass reduction was modelled mathematically, the speed profiles of 100 m wheelchair races as well as the rolling resistance and drag area of the athlete–wheelchair system was determined experimentally, and the improvement of the winning time through mass reduction was calculated from the mathematical model and experimental data. For winning times of 30 s, the relative improvement of the winning time is at least equal to the relative reduction of mass. For winning times of 15 s, the relative improvement of the winning time is at least half the relative reduction of mass. A reduction by 1 kg results in an overall improvement of the winning time of about 1–2.3% for winning times of 15–30 s (100-m race). In absolute terms, a mass saving of 1 and 5 kg on a 60-kg system would reduce a 15-s winning time for the 100 m by 0.132 and 0.66 s, respectively, and a 30-s winning time by 0.63 and 2.86 s, respectively. The mass of a wheelchair is the most important parameter for improving the winning time. The influence of the mass on the winning time is 4 or 1.5 times greater than the influence of the rolling friction coefficient, and 4 or 5.5 times greater than the influence of the drag area in a 15 or 30-s race, respectively. These principles should be considered when designing a racing wheelchair.

Effect of Segmental Velocity Increments On Maximum Wheelchair Racing Speed

PURPOSE: Biomechanical characteristics in wheelchair propulsion such as range of motions, segment velocities and accelerations, and pushrim forces and moments have been broadly documented; however, the effect of segmental velocities on wheelchair racing have not been investigated. This study was to determine the effect of linear segmental velocity increments of the upper extremity on the maximum wheel speed (MWS) in wheelchair racing. METHODS: Seventeen elite international wheelchair racers with the mean age of 30.3 ± 7.0 yrs, body mass 57.5 ± 10.2 kg and wheelchair racing training 8.9 ± 6.6 yrs served as participants. Reflective markers were placed on right 5th metacarpal head (hand), lateral styloid process (wrist), lateral epicondyle of the humerus (elbow) and acromion (shoulder), as well as the right wheel. Participants were filmed at 100Hz by a three-dimensional motion system while propelling their own racing wheelchairs on a training roller at their maximum speeds. After shoulder, elbow, wrist and hand linear velocities in the drive phase were calculated, linear segmental velocity increments were derived based on the difference of peak linear velocities between two adjacent joints, including shoulder-to-elbow (SE), elbow-to-wrist (EW) and wrist-to-hand (WH) velocity increments. A multiple linear regression was employed to determine the effect of each increment on the MWS. RESULTS: Mean peak linear velocities were 2.04 ± 0.38 m/s for the shoulder, 5.14 ± 0.83 m/s for the elbow, 6.26 ± 1.15 m/s for the wrist and 7.53 ± 1.03 m/s for the hand. The mean MWS was 9.14 ± 1.72 m/s. Peak linear velocities increased from proximal to distal joints, specifically from shoulder to the elbow (from 2.04 to 5.14 m/s). It was shown 87% of the variance of the MWS was accounted for by segmental velocity increments (P < 0.01) with the greatest contribution from WH and the least contribution from EW (MWS = -21.92 + 1.67SE + 1.42EW + 2.02WH). CONCLUSIONS: It is speculated that increasing wrist linear velocity by performing more abduction/addition in the drive phase may improve the wheelchair racing speed. Supported by the Roosevelt Warm Springs Institute for Rehabilitation, Warm Springs, GA

Biceps And Triceps Oxygenation Changes In Competitive Wheelchair Racers With Spinal Cord Injury

Biceps And Triceps Oxygenation Changes In Competitive Wheelchair Racers With Spinal Cord Injury

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

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.

Effects of Respiratory Muscle Endurance Training on Wheelchair Racing Performance in Athletes With Paraplegia: A Pilot Study

Respiratory muscle endurance training (RMET) has been shown to improve both respiratory muscle and cycling exercise endurance in able-bodied subjects. Since effects of RMET on upper extremity exercise performance have not yet been investigated, we evaluated the effects of RMET on 10-km time-trial performance in wheelchair racing athletes. Pilot study, controlled before and after trial. Spinal cord injury research center. 12 competitive wheelchair racing athletes. The training group performed 30 sessions of RMET for 30 min each. The control group did no respiratory muscle training. Differences in 10-km time-trial performance pre- versus postintervention. In the training group, the time of the 10-km time-trial decreased significantly from before versus after intervention (27.1 +/- 9.0 vs. 24.1 +/- 6.6 min); this did not occur in the control group (23.3 +/- 2.8 vs. 23.2 +/- 2.4 min). No between groups difference was present (P = 0.150). Respiratory muscle endurance increased significantly within the training group (9.1 +/- 7.2 vs. 39.9 +/- 17.8 min) and between groups, but not within the control group (4.3 +/- 2.9 vs. 6.6 +/- 7.0 min) before versus after intervention. There was a strong trend, with a large observed effect size of d = 0.87, towards improved performance in the 10-km time-trial after 6 weeks of RMET.

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

Although pushrim kinematics of racing wheelchair propulsions (RWP) has been widely investigated, pushrim kinetics is very limited due to the complexity of pushrim force measurement device. At present, only one study explored pushrim kinetics and reported the tangential and axial forces during RWP. PURPOSE: To determine the three-dimensional (3-D) pushrim forces and compared the pushrim forces during RWP among three different propulsive speeds METHODS: Five experienced male wheelchair racers who classified as T52-T54, mean age of 28.4 (6.87) years, volunteered for this study. Kinetic data were obtained from an instrumented wheel system which incorporated JR-3 force transducer attached to the right wheel axle. Three retroreflective markers were placed on the right side of second metacarpophalangeal joint, the fifth metacarpophalangeal joint, and the midpoint between radial and ulna styloid processes. Two retroreflective markers were placed on the wheel in order to obtain wheel angular positions. Six 120-Hz optical cameras were used to acquire kinematics data. Both kinematics and kinetics data were collected synchronously at 90%, 70%, and 50% of the maximum RWP speeds on a roller system. Three trials were recorded on each speed conditions with a duration of 30 seconds for each trial. The Friedman test was employed to determine the different pushrim forces for the three speed conditions. RESULTS: Among the generated 3-D pushrim forces, peak radial force was the highest force on all speed conditions. The peak radial forces of 50%, 70%, and 90% of RWP were 104.6 N, 123.5 N and 136 N respectively. These peak radial forces were significantly increased from 50% to 70%, and from 70% to 90% speed conditions (p<0.05). CONCLUSIONS: As propulsive speed increases, all pushrim forces (the tangential, radial, and axial forces) increase. Radial force was found to be the greatest force and increased significantly which may lead to potential joint injuries of upper extremities.

Optimizing Performance of Wheelchair Racing

Optimizing Performance of Wheelchair Racing

Kinematic analysis of the 100-m wheelchair race

The purpose of this study was to compare the speed and selected stroke cycle characteristics during different phases of the 100-m wheelchair race for paraplegic athletes. Four male and two female wheelchair racers in T4 classification and one male and three female athletes in T3 classification served as the participants. Two S-VHS camcorders (60 fields/s) were panned horizontally to cover the first and second 50 m of the 100-m race, respectively. Average speed, stroke length and frequency, contact and recovery times during the first 10 m (initial acceleration phase, IAP), the maximum speed phase (MSP), and the last 10 m (final phase, FP) of the race were determined. For each parameter, an ANOVA with repeated measures was performed and Tukey post hoc tests were completed when appropriate ( α=0.01). The 100-m times ranged from 16.10 to 22.18 s. Significant differences were found between IAP and MSP and between IAP and FP in stroke speed, stroke length, and push and recovery times, but not in stroke frequency. The relatively constant stroke frequency across different phases may suggest that wheelchair racers like to maintain the same stroking rhythm throughout a 100-m race. The distance and time needed to reach the maximum speed ranged from 43.9 m and 11.2 s to 82.2 m and 18.9 s, respectively. The significant correlation between 100-m time and maximum speed ( p<0.001) signifies the importance of maximum speed in determining 100-m performance.