Exercise intensity during wheelchair rugby training

Abstract

The purpose of this study was to determine the ability of individuals with a cervical spinal cord injury to achieve and sustain a cardiorespiratory training intensity during wheelchair rugby. Nine wheelchair rugby players completed a continuous peak exercise test on a SciFit Pro I arm ergometer with stage increases each minute to determine peak heart rate and power output. Approximately one week after peak exercise testing, heart rate was recorded (every 5 s) during three regularly scheduled rugby training sessions. Data were analysed to determine the number of continuous minutes that participants spent above 70% of heart rate reserve under various rugby training activities. The percent of time spent at or above 70% heart rate reserve varied across participants and conditions. Continuous pushing was the least variable training condition among participants with the sample averaging greater than 73% of time above the target heart rate. Scrimmage training was highly variable across participants with a range of 0% to 98% of time above the criterion. Results of this study indicate that wheelchair rugby training enables some participants to reach a training intensity associated with improved cardiorespiratory fitness, and that the type (or kind) of training activity dictates the extent to which individuals sustain such a threshold.     

A physiological and biomechanical comparison of over-ground,treadmill and ergometer wheelchair propulsion

Abstract

The purpose of the study was to determine which laboratory-based modality provides the most valid physiological and biomechanical representation of over-ground sports wheelchair propulsion. Fifteen able-bodied participants with previous experience of wheelchair propulsion performed a 3-minute exercise trial at three speeds (4, 6 and 8 km ? h^–1) in three testing modalities over separate sessions: (i) over-ground propulsion on a wooden sprung surface; (ii) wheelchair ergometer propulsion; (iii) treadmill propulsion at four different gradients (0%, 0.7%, 1.0% and 1,3%). A 0.7% treadmill gradient was shown to best reflect the oxygen uptake (7.3 to 9.1% coefficient of variation (CV)) and heart rate responses (4.9 to 6.4% CV) of over-ground propulsion at 4 and 6 km ? h^–1. A 1.0% treadmill gradient provided a more valid representation of oxygen uptake during over-ground propulsion at 8 km ? h^–1 (8.6% CV). Physiological demand was significantly underestimated in the 0% gradient and overestimated in the 1.3% gradient and wheelchair ergometer trials compared to over-ground trials (P<0.05). No laboratory-based modality provided a valid representation of the forces applied during OG (≥ 18.4% CV). To conclude, a 0.7% treadmill gradient is recommended to replicate over-ground wheelchair propulsion at lower speeds (4 and 6 km ? h^–1) whereas a 1.0% gradient may be more suitable at 8 km ? h^–1.     

Autonomic modulation of heart rate in paraplegic wheelchair basketball players: Linear and nonlinear analysis

Abstract

This study aimed to evaluate the autonomic modulation of heart rate in sedentary paraplegics and paraplegic wheelchair basketball players with thoracic spinal cord injury below T6. Seven paraplegic wheelchair basketball players (active paraplegic group), five paraplegics who were not involved in regular exercise (sedentary paraplegic group) and 10 able-bodied participants (control group) took part in the study. The heart rate variability was evaluated by linear (low frequency and high frequency band in normalised units and low frequency/high frequency ratio) and nonlinear methods (Shannon entropy, corrected conditional entropy, and symbolic analysis).

The sedentary group presented significantly higher values for low frequency, low frequency/high frequency ratio and symbolic index with no significant variations (0V%), and also lower values for the high frequency and symbolic index with two significant unlike variation (2ULV%) compared to active paraplegic group. Shannon entropy and corrected conditional entropy analyses revealed significantly lower values in the sedentary group than in the control or active paraplegic groups. Paraplegic individuals who regularly undertake physical exercise have higher complexity of R-R interval time series, lower sympathetic modulation, and higher parasympathetic modulation than sedentary paraplegic participants.     

Elite wheelchair rugby: a quantitative analysis of chair configuration in Australia

Limited recommendations of wheelchair configurations for court sports have been identified in the published literature. To accommodate the wide range of impairments in wheelchair rugby, players are given a point score that reflects their impairment. Players have regularly been grouped as high-, mid-, or low-point players in research, with high-point players having greater levels of muscle function compared with other classifications. This research documented the wheelchair configurations of elite Australian wheelchair rugby players across classification groups. Significant differences (p < 0.05) were found for increased seat height and decreased seat depth for high-point players compared with low- and mid-point groups, respectively. Low-point players displayed reduced wheelchair mass compared with high- and mid-point players, as well as increased frame length. Camber angles showed no significant differences across the classification groups. The incorporation of anthropometric measures, such as the elbow angle at the top dead center, was also investigated. While elbow angle showed no significant differences, seat height-to-total arm length ratio was higher for high-point players. Participants also completed surveys detailing their perception of the effect of altering wheelchair configurations. It is suggested that wheelchair configurations should consider an individual’s anthropometrics, impairment, training history, and court role to promote optimal performance, with predictive modeling having the potential to reduce the associated time and cost.     

Force-velocity characteristics of upper limb extension during maximal wheelchair sprinting performed by healthy able-bodied females

The aim of this study was to determine the relationship between force and velocity parameters during a specific multi-articular upper limb movement--namely, hand rim propulsion on a wheelchair ergometer. Seventeen healthy able-bodied females performed nine maximal sprints of 8 s duration with friction torques varying from 0 to 4 N x m. The wheelchair ergometer system allows measurement of forces exerted on the wheels and linear velocity of the wheel at 100 Hz. These data were averaged for the duration of each arm cycle. Peak force and the corresponding maximal velocity were determined during three consecutive arm cycles for each sprint condition. Individual force-velocity relationships were established for peak force and velocity using data for the nine sprints. In line with the results of previous studies on leg cycling or arm cranking, the force-velocity relationship was linear in all participants (r = -0.798 to -0.983, P < 0.01). The maximal power output (mean 1.28 W x kg(-1)) and the corresponding optimal velocity (1.49 m x s(-1)) and optimal force (52.3 N) calculated from the individual force-velocity regression were comparable with values reported in the literature during 20 or 30 s wheelchair sprints, but lower than those obtained during maximal arm cranking. A positive linear relationship (r = 0.678, P < 0.01) was found between maximal power and optimal velocity. Our findings suggest that although absolute values of force, velocity and power depend on the type of movement, the force-velocity relationship obtained in multi-articular limb action is similar to that obtained in wheelchair locomotion, cycling and arm cranking.     

Activity identification and classification in wheelchair rugby using fractal dimensions

The purpose of the study was to develop an evidence-based method for identification and classification of wheelchair sports (rugby) activities and performance during a match using fractal dimensions. The approach involves five wheelchair rugby athletes of different classifications who were monitored during six different matches using mobile devices with in-built accelerometers. The linear acceleration signals were processed using two different approaches based on calculating fractal dimensions. One was based on Rényi’s entropy, which produced the probability dimension (S ₀), and the other was based on Hausdorff’s definition, resulting in the Hausdorff dimension (D _H). When both dimensions were individually plotted as cumulative distribution plots, they offered two approaches to analyze the performance of a wheelchair rugby athlete. Combining the two dimensions produced a two-dimensional (2D) mapping that identified five different activities of each athlete during a wheelchair rugby match—(1) no activities, (2) low activities, (3) high-speed coasting, (4) high-speed pushing, and (5) extreme collisions. In the 2D mapping, four boundary lines separate the five different activities, which produced a template for each athlete. It was found in this research that the classification and skill level of the athlete had an effect on the boundary line values that form the template. The outcome of the activity identification was also verified by comparing with video footage of the athletes. The method developed in this research has possible applications for coaching, match analysis, and talent identification.     

Data logger device applicability for wheelchair tennis court movement

Assessment of movement logging devices is required to ensure suitability for the determination of court-movement variables during competitive sports performance and allow for practical recommendations to be made. Hence, the purpose was to examine wheelchair tennis speed profiles to assess data logger device applicability for court-movement quantification, with match play stratified by rank (HIGH, LOW), sex (male, female) and format (singles, doubles). Thirty-one wheelchair tennis players were monitored during competitive match play. Mixed sampling was employed (male = 23, female = 8). Friedman’s test with Wilcoxon signed-rank post hoc testing revealed a higher percentage of time below 2.5 m · s^?1 [<2.5 vs. ≥2.5 m · s^?1: 89.4 (5.0) vs. 1.2 (3.5)%, Z = ?4.860, P < 0.0005, r = 0.87] with the remaining time [9.0 (4.9%)] spent stationary. LOW-ranked players were stationary for longer than HIGH-ranked counterparts [12.6 (8.7) vs. 8.2 (5.1)%, U = 30.000, P = 0.011, r = 0.46] with more time at low propulsion speeds (<1.0 m · s^?1). HIGH-ranked and doubles players spent more time in higher speed zones than respective counterparts. Females spent more time in the 1.0–1.49 m · s^?1 zone (U = 48.000, P = 0.047, r = 0.36). Regardless of rank, sex or format, propulsion speeds during wheelchair tennis match play are consistent with data logger accuracy. Hence, data logging is appropriate for court-movement quantification.     

Non-disabled secondary school children's lived experiences of a wheelchair basketball programme delivered in the East of England

Frequently an unquestioned belief is held in British schools in the value of ‘normalized’ ability in physical education (PE). Consequently inclusion of disabled students can be problematic. Negative perceptions of disability are rarely challenged. This study investigated the embodied experiences of 49 non-disabled secondary school pupils during a programme designed to introduce disability sport to non-disabled school children entitled ‘The Wheelchair Sports Project’. Funded by a County Sports Partnership, Wheelchair Basketball sessions were delivered by trained coaches during PE for a 12-week period. Forty-nine pupils aged between 10 and 12 years took part in the study. Non-participant observations were completed during the programme, and semi-structured group interviews were completed with 24 participants pre- and post-project. Bourdieu's theoretical framework guided data analysis. The impact of the project on pupils' perceptions of physical disability was investigated. Prior to the project, pupils emphasized the ‘otherness’ of disabled bodies and described disability sport as inferior and not ‘real’. Observations highlighted how pupils experienced physical challenges adapting to wheelchair basketball. Pupils struggled to control wheelchairs and frequently diverged from acceptable behaviour by using their lower limbs to ‘cheat’. Post-programme group interviews demonstrated that, due to their own embodied experiences, pupils began to question their perceptions of the potential ability of participants with physical impairments. Pupils described high physical demands of wheelchair basketball and began to focus upon similarities between themselves and physically disabled individuals. However, participants made no reference to impairments other than physical disability, emphasizing the specificity of the effects of pupils' embodied experiences on their embodied habitus, which, although difficult to assess over the long term, appeared to have an impact on self-perceptions over the short term.     

The validity and reliability of a novel indoor player tracking system for use within wheelchair court sports

Abstract

The aim of the current study was to investigate the validity and reliability of a radio frequency-based system for accurately tracking athlete movement within wheelchair court sports. Four wheelchair-specific tests were devised to assess the system during (i) static measurements; (ii) incremental fixed speeds; (iii) peak speeds; and (iv) multidirectional movements. During each test, three sampling frequencies (4, 8 and 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19 and 0.32 m across the session. Distance values (test (ii)) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (<1.0%). Relative peak speed errors of <2.0% (test (iii)) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m · sˉ¹). Results showed 8 and 16 Hz sampling frequencies displayed the closest-to-criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (<0.2%) were also seen across sampling frequencies (test (iv)). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match play using a tag frequency of 8 or 16 Hz.     

残奥会轮椅乒乓球运动员攻防动作的力学分析

通过对国家队多名乒乓球轮椅运动员对抗性训练时的攻防动作的观察,结合力学原理进行分析,发现:在轮椅乒乓球比赛中,在进攻方面——在大力扣杀时,执拍手的加速运动所产生的惯性力会使轮椅产生旋转,形成人体——轮椅系统绕垂直轴的相向运动;挥臂的转动半径越大,转动惯量就大,启动就慢;挥臂的转动半径小,击球速度就慢,反之就大。在防守方面——存在一个防守"小三角",即在球台靠近网与边线的交界处,有两个呈三角形的区域,也可叫轮椅乒乓球的死角区;小三角的大小与运动员手臂的长短、轮椅的位置、用力的方式等诸多因素有关。在实战中,在初始选位时,运动员可根据自身的特点以及对手的情况,对轮椅进行适当的左右位置的调整。     

The effect of active sitting on trunk motion

BackgroundProlonged sitting is a risk factor for low-back pain. The primary purpose of this study is to determine if prolonged active sitting will result in increased trunk motion.MethodsFifteen healthy female participants volunteered to sit for 30 min on each of three surfaces including an air-cushion, a stability ball, and a hard surface. Trunk motion was monitored using a Vicon motion capture system, and foot center of pressure was collected with two AMTI force plates.ResultsOur findings indicated that the average speed of the trunk center of mass significantly increased with seating surface compliance. There were significant differences in right and left foot centers of pressure in the antero-posterior direction between the ball and air-cushion conditions and the ball and chair conditions.ConclusionActive sitting results in increased trunk motion and could have a positive effect on low-back health.     

我国轮椅篮球的现状及发展对策研究

轮椅篮球在我国虽有十几年的发展历史,但由于起步较晚,以及运动员选材、场地、器材、宣传、资金投入、训练水平等各种因素的影响,整体水平不高,和世界强队相比存在较大差距。运用文献资料法、问卷调查法对我国目前轮椅篮球运动的现状进行研究,找出了影响轮椅篮球运动发展的因素,并提出解决方案。     

Effect of short-term application of kinesio tape on the flexion-relaxation phenomenon,trunk postural control and trunk repositioning in healthy females

This study was designed to investigate the potential effects of kinesio tape on the flexion-relaxation phenomenon, trunk postural control and trunk position sense when applied for a short period (30 min) to the low back of healthy female participants. Twenty-four participants were assigned to one of two groups: kinesio tape applied in either the recommended stretched or non-stretched (control) manner over the low back. Tests were performed at three time points (pre-tape, with tape, post-tape) to assess low-back muscle flexion-relaxation, position sense during active trunk repositioning and trunk postural control during seated balance. Results demonstrated that wearing kinesio tape did not affect the angle at which the erector spinae muscles became silent during trunk flexion (flexion-relaxation). Trunk repositioning error increased when wearing kinesio tape in both the stretched and non-stretched manner, and this increased error persisted after the tape was removed. Seated balance control improved when wearing kinesio tape in both the stretched and non-stretched manner, and these improvements persisted after the tape was removed. In conclusion, these findings do not support the general suggestions that short-term use of kinesio tape on the low-back region alter low-back muscle activation and enhance tasks related to proprioception, at least under these taping conditions in a group of healthy females.     

Training Visual Control in Wheelchair Basketball Shooting

We examined the effects of visual control training on expert wheelchair basketball shooting, a skill more difficult than in regular basketball, as players shoot from a seated position to the same rim height. The training consisted of shooting with a visual constraint that forced participants to use target information as late as possible. Participants drove under a large screen that initially blocked the basket. As soon as they saw the basket they shot. When training with the screen, shooting percentages increased. We conclude that visual control training is an effective method to improve wheelchair basketball shooting. The findings support the idea that perceptualmotor learning can be enhanced by manipulating relevant constraints in the training environment, even for expert athletes.     

Impact of short- compared to long-haul international travel on the sleep and wellbeing of national wheelchair basketball athletes

Currently, very little is known about the impact of short- or long-haul air travel on the sleep and wellbeing of wheelchair basketball athletes. Eleven national wheelchair basketball athletes wore actigraphy monitors prior, during, and after air travel to the United Kingdom. Upon arrival, participants rated their subjective jet-lag, fatigue, and vigor. Individuals traveled to the United Kingdom from different locations in Australia, the United States, and Europe and were categorised according to travel length [LONG (up to 30.2 h) or SHORT (up to 6.5 h)]. Linear mixed models determined effects of travel length on sleep and subjective ratings of jet-lag, fatigue, and vigor. During competition, subjective fatigue and jet-lag were substantially higher (ES = 0.73; ±0.77) and (ES = 0.57; ±0.60), subjective vigor was lower (ES = 1.94; ±0.72), and get-up time was earlier (ES = 0.57; ±0.60) for LONG when compared to SHORT. Travelling greater distances by airplane had a larger effect on subjective ratings of jet-lag, fatigue and vigor, rather than sleep. Irrespective of travel group, sleep and subjective responses were compromised, reflecting the travel requirements, competition-mediated influences, and/or due to a change in environment.     

The multi-stage fitness test as a predictor of endurance fitness in wheelchair athletes

The aims of this study were two-fold: (1) to consider the criterion-related validity of the multi-stage fitness test (MSFT) by comparing the predicted maximal oxygen uptake (.VO(2max)) and distance travelled with peak oxygen uptake (VO(2peak)) measured using a wheelchair ergometer (n = 24); and (2) to assess the reliability of the MSFT in a sub-sample of wheelchair athletes (n = 10) measured on two occasions. Twenty-four trained male wheelchair basketball players (mean age 29 years, s = 6) took part in the study. All participants performed a continuous incremental wheelchair ergometer test to volitional exhaustion to determine .VO(2peak), and the MSFT on an indoor wooden basketball court. Mean ergometer .VO(2peak) was 2.66 litres . min(-1) (s = 0.49) and peak heart rate was 188 beats . min(-1) (s = 10). The group mean MSFT distance travelled was 2056 m (s = 272) and mean peak heart rate was 186 beats . min(-1) (s = 11). Low to moderate correlations (rho = 0.39 to 0.58; 95% confidence interval [CI]: -0.02 to 0.69 and 0.23 to 0.80) were found between distance travelled in the MSFT and different expressions of wheelchair ergometer .VO(2peak). There was a mean bias of -1.9 beats . min(-1) (95% CI: -5.9 to 2.0) and standard error of measurement of 6.6 beats . min(-1) (95% CI: 5.4 to 8.8) between the ergometer and MSFT peak heart rates. A similar comparison of ergometer and predicted MSFT .VO(2peak) values revealed a large mean systematic bias of 15.3 ml . kg(-1) . min(-1) (95% CI: 13.2 to 17.4) and standard error of measurement of 3.5 ml . kg(-1) . min(-1) (95% CI: 2.8 to 4.6). Small standard errors of measurement for MSFT distance travelled (86 m; 95% CI: 59 to 157) and MSFT peak heart rate (2.4 beats . min(-1); 95% CI: 1.7 to 4.5) suggest that these variables can be measured reliably. The results suggest that the multi-stage fitness test provides reliable data with this population, but does not fully reflect the aerobic capacity of wheelchair athletes directly.     

对轮椅车前轮举起动作的研究

轮椅车的前轮举起动作是通过肘关节的用力伸展,给予轮椅车以前进的加速度,并由此产生一个惯性力,轮椅车以后车轴为旋转中心产生旋转。目前轮椅车前轮举起动作的训练方法,主要有床架法和借助法两种。     

中国轮椅篮球运动发展状况的研究

本文采用文献资料、问卷调查、专家访谈和数理统计等方法,对我国轮椅篮球运动的发展状况进行了调查研究。结果表明,中国轮椅篮球运动隶属中国残疾人体育协会,轮椅篮球队伍比较稳定,运动员年龄跨度较大,以中度残疾者为主,训练年限普遍较短,教练员多属兼职且年龄较大,篮球执教经历丰富,但对轮椅篮球规律认识不深。目前我国轮椅篮球训练条件较差,参加比赛均采用赛前集训形式,且比赛机会较少。     

Multidimensional joint coupling: a case study visualisation approach to movement coordination and variability

Abstract

A case study visualisation approach to examining the coordination and variability of multiple interacting segments is presented using a whole-body gymnastic skill as the task example. One elite male gymnast performed 10 trials of 10 longswings whilst three-dimensional locations of joint centres were tracked using a motion analysis system. Segment angles were used to define coupling between the arms and trunk, trunk and thighs and thighs and shanks. Rectified continuous relative phase profiles for each interacting couple for 80 longswings were produced. Graphical representations of coordination couplings are presented that include the traditional single coupling, followed by the relational dynamics of two couplings and finally three couplings simultaneously plotted. This method highlights the power of visualisation of movement dynamics and identifies properties of the global interacting segmental couplings that a more formal analysis may not reveal. Visualisation precedes and informs the appropriate qualitative and quantitative analysis of the dynamics.