Maximal exercise response of paraplegic wheelchair road racers

Design of an adjustable wheelchair for table tennis participation

PURPOSE

Physical activity and recreation are very important for people with disabilities and provide benefits for self-esteem, social relationships, employment, rehabilitation, and education. Para Table Tennis is an adaptive sport where participants compete in table tennis while sitting in a wheelchair. However, athletes generally use their everyday wheelchair instead of a device specifically designed for the sport. The specific support, movements, and posture needed to participate in table tennis at the highest level are different than general day-to-day mobility and a device could be optimized for the sport. This research describes the development of a wheelchair specifically designed for para table tennis.

MATERIALS AND METHODS

The design followed a participatory action design approach which identified the specific needs for a wheelchair to be used during para table tennis.

RESULTS

Three design needs were identified which included 1) locking the casters in the forward direction, 2) ability to raise the seat height as high as possible while allowing the user's knees to fit under the table, and 3) adjustable seat angle which will allow some users to have anterior tilt to get their trunk even higher while other users could have posterior tilt for stability. A new chair meeting these needs was designed and prototyped.

CONCLUSIONS

Para table tennis has some specific requirements related to movements and posture which were improved by a new wheelchair design specific for the sport.IMPLICATIONS FOR REHABILITATIONMany adaptive sports are improved with sport specific technology.A model client was used to develop a wheelchair specifically for adaptive table tennis.The height and angle of the seat of the new wheelchair can be adjusted for optimal stability and reach.The casters of the new wheelchair can be locked to allow only forward and backward motion.

Robust Control Design of Heart Rate Response during Treadmill Exercise under Parametric Uncertainty

Rehabilitation (Rehab) exercise can benefit cardiac patients as it can promote the recovery and improve the heart wellness. However, heart failure (HF) patients can only take mild exercise, since excessive exercise may lead to fatal events. It is important to control the exercise intensity at a desired level to maximize exercise benefit. Heart Rate (HR) is an essential factor for measuring exercise intensity. Mathematical models of HR can be used to study exercise physiology. However, HR models involve model uncertainty, resulting from model calibration or variability in patients. It is important to quantify the effect of uncertainty on HR prediction for optimizing exercise intensity, such as treadmill speed. A probabilistic model-based control design is presented in this work to obtain an optimal treadmill speed for Rehab exercise in the presence of uncertainty. To obtain a computationally tractable formulation, the generalized polynomial chaos (gPC) theory is used to propagate uncertainty via a model to HR predictions, and predict slow-acting responses such as peripheral local metabolism that can be used to evaluate exercise outcome for individual patients. The speed control of treadmill is formulated as an optimization problem that can maximize the exercise outcome, while minimizing the slow-acting effects. The effectiveness of the proposed control design was experimentally verified with simulations, showing potentials in the exercise control of individual patients.

Exercise loading for cardiopulmonary assessment and evaluation of endurance in amputee football players

[Purpose] It is difficult for amputees to perform conventional cardiopulmonary exercise testing. Values were determined for two-legged, one-legged, and two-armed exercise testing in healthy adult males (Study 1), for comparison with preliminary measurements of endurance in amputee football players (Study 2). [Participants and Methods] In Study 1, cardiopulmonary exercise testing was performed in healthy adult males. Correlations between oxygen uptake in two-legged and one-legged/two-armed exercise were calculated and a comparison was made between one-legged exercise and two-armed exercise for each measured value. In Study 2, cardiopulmonary exercise testing was performed on male amputee football players using a two-arm-driven ergometer. The measured values obtained for healthy adult males and amputee football players were compared. [Results] In Study 1, peak work rate and peak heart rate values of healthy participants were significantly higher in two-armed exercise than in one-legged exercise. The correlation between peak oxygen uptake values for two-legged and one-legged exercise was decreased. In Study 2, peak work rate of two-armed exercise was significantly higher in amputee football players than in healthy participants. [Conclusion] Study 1 suggested that musculoskeletal factors might have greater significance for one-legged exercise than for two-armed exercise. Study 2 suggested that para-sports, including amputee football, may contribute to physical strength and health maintenance in lower leg amputees.

Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis

Background

Peak oxygen uptake (VO_2peak) in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested.

Objectives

To identify VO_2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO_2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO_2peak.

Design

Systematic literature review and meta-analysis.

Data sources

PubMed, CINAHL, SPORTDiscus^TM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean.

Eligibility criteria

Studies that assessed VO_2peak values in sitting sports athletes with a disability in a laboratory setting were included.

Data synthesis

Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO_2peak.

Results

Of 6542 retrieved articles, 57 studies reporting VO_2peak values in 14 different sitting sports were included in this review. VO_2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO_2peak values ranged from 2.9 L∙min^-1 and 45.6 mL∙kg^-1∙min^-1 in Nordic sit skiing to 1.4 L∙min^-1 and 17.3 mL∙kg^-1∙min^-1 in shooting and 1.3 L∙min^-1 and 18.9 mL∙kg^-1∙min^-1 in wheelchair rugby. Large within-sports variation was found in sports with few included studies and corresponding low sample sizes. The meta-regression and pooled-data multiple regression analyses showed that being a man, having an amputation, not being tetraplegic, testing in a wheelchair ergometer and treadmill mode, were found to be favorable for high absolute and body-mass normalized VO_2peak values. Furthermore, high body mass was favourable for high absolute VO_2peak values and low body mass for high body-mass normalized VO_2peak values.

Conclusion

The highest VO_2peak values were found in Nordic sit skiing, an endurance sport with continuously high physical efforts, and the lowest values in shooting, a sport with low levels of displacement, and in wheelchair rugby where mainly athletes with tetraplegia compete. However, VO_2peak values need to be interpreted carefully in sports-disciplines with few included studies and large within-sports variation. Future studies should include detailed information on training status, sex, age, test mode, as well as the type and extent of disability in order to more precisely evaluate the effect of these factors on VO_2peak.

Real-time modelling of heart rate response during exercise using a novel constrained parameter estimation method

This paper is devoted to the problem of real-time heart rate (HR) response modelling during treadmill exercise. A novel recursive constrained parameter estimation method is developed which in contrast to the conventional parameter estimation schemes (e.g. recursive least squares (RLS) method) can avoid the occurrence of the so-called blowup phenomena. By incorporation of a weighting upon 1) parameter variation relative to a priori HR response knowledge, 2) one-step parameter variation, into the objective function, an estimation scheme is obtained that in the absence of exciting data can avoid blowup. The proposed estimation scheme were experimentally verified using eight healthy male subjects and the results demonstrated that the designed scheme is able to identify the HR response of the exercising subjects in a real-time manner. As HR response is naturally a time-varying dynamics, the proposed online modelling method is of importance for the HR regulation during exercises, using a feedback controller with a desirable level of performance.

Heart rate regulation during cycle-ergometer exercise via event-driven biofeedback

This paper is devoted to the problem of regulating the heart rate response along a predetermined reference profile, for cycle-ergometer exercises designed for training or cardio-respiratory rehabilitation. The controller designed in this study is a non-conventional, non-model-based, proportional, integral and derivative (PID) controller. The PID controller commands can be transmitted as biofeedback auditory commands, which can be heard and interpreted by the exercising subject to increase or reduce exercise intensity. However, in such a case, for the purposes of effectively communicating to the exercising subject a change in the required exercise intensity, the timing of this feedback signal relative to the position of the pedals becomes critical. A feedback signal delivered when the pedals are not in a suitable position to efficiently exert force may be ineffective and this may, in turn, lead to the cognitive disengagement of the user from the feedback controller. This note examines a novel form of control system which has been expressly designed for this project. The system is called an "actuator-based event-driven control system". The proposed control system was experimentally verified using 24 healthy male subjects who were randomly divided into two separate groups, along with cross-validation scheme. A statistical analysis was employed to test the generalisation of the PID tunes, derived based on the average transfer functions of the two groups, and it revealed that there were no significant differences between the mean values of root mean square of the tracking error of two groups (3.9 vs. 3.7 bpm, [Formula: see text]). Furthermore, the results of a second statistical hypothesis test showed that the proposed PID controller with novel synchronised biofeedback mechanism has better performance compared to a conventional PID controller with a fixed-rate biofeedback mechanism (Group 1: 3.9 vs. 5.0 bpm, Group 2: 3.7 vs. 4.4 bpm, [Formula: see text]).

Effects of Krankcycle Training on Performance and Body Composition in Wheelchair Users

Innovation in training equipment is important for increasing training effectiveness, performance and changes in body composition, especially in wheelchair users with paraplegia. The main objective of a workout session is to induce an adaptation stimulus, which requires overload of involved muscles by voluntary effort, yet this overload may be highly influenced by the size of the spinal cord lesion. Krancykl construction is designed to allow exercise on any wheelchair and with adjustable height or width of crank handles, where even the grip handle may be altered. The aim of this study was to determine the differences in body composition, performance and the rate of perceived exertion (RPE) in paraplegics with a different level of paralyses after a 12 week training programme of a unilateral regime on Krankcycle equipment (a crank machine). The study sample included four men and one women at a different spine lesion level. The 12 weeks programme was successfully completed by four participants, while one subject got injured during the intervention process. Three participants were paraplegics and one was quadriplegic with innervation of the biceps humeri, triceps humeri and deltoideus. The Krankcycle 30 min programme was followed by four other exercises, which were performed after themselves rather than in a circuit training manner as the latter would result in much longer rest periods between exercises, because paraplegics have to be fixed by straps during exercise on hydraulic machines. The RPE after the workout decreased following the twelve week adaptation period.

Sport participation by physically and cognitively challenged young athletes

Many physically and cognitively challenged athletes participate in organized and recreational sports. Health benefits of sport participation by athletes with disabilities have been well recognized. A careful preparticipation evaluation and proper classification of athletes ensures safe sports participation by athletes with disabilities. Some conditions in these athletes, such as problems with thermoregulation, autonomic control, neurogenic bladder and bowel, latex allergy, and many associated and secondary complications deserve special consideration. This article reviews common medical issues that relate to sport participation by athletes with physical and cognitive disabilities.

Modelling and control for heart rate regulation during treadmill exercise

This paper proposes a novel integrated approach for the identification and control of Hammerstein systems to achieve desired heart rate tracking performance for an automated treadmill system. The pseudo-random binary sequence input is employed to decouple the identification of dynamic linear part from static nonlinearity. The powerful e-insensitivity support vector regression is adopted to obtain sparse representations of the inversion of static nonlinearity in order to obtain an approximated linear model of the Hammerstein system. An H(infinity) controller is designed for the approximated linear model to achieve robust tracking performance. This new approach is applied to the design of a computer-controlled treadmill system for the regulation of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed of the treadmill. Both conventional proportional-integral-derivative (PID) control and the proposed approaches have been employed for the controller design. The proposed algorithm achieves much better heart rate tracking performance.

A handle electrode system for measuring heart rate while riding a bicycle

In this paper, a handle-electrode system is proposed for obtaining the heart rate of a user while riding a bicycle. The system was designed to measure the user's heart rate by only gripping the handle of a bicycle. Three electrodes made from conductive cloth were adhered to the handle. A method detecting heart-rate from the obtained electrocardiogram was also proposed. To assess the applicability of the proposed system, a simple experiment was performed. The experiment was performed in four conditions of road surfaces; lawn, asphalt, a tiled, and an uneven road. Experimental result suggests that the proposed system can be useful for obtaining R waves while riding a bicycle.

Nonparametric Hammerstein model based model predictive control for heart rate regulation

This paper proposed a novel nonparametric model based model predictive control approach for the regulation of heart rate during treadmill exercise. As the model structure of human cardiovascular system is often hard to determine, nonparametric modelling is a more realistic manner to describe complex behaviours of cardiovascular system. This paper presents a new nonparametric Hammerstein model identification approach for heart rate response modelling. Based on the pseudo-random binary sequence experiment data, we decouple the identification of linear dynamic part and input nonlinearity of the Hammerstein system. Correlation analysis is applied to acquire step response of linear dynamic component. Support Vector Regression is adopted to obtain a nonparametric description of the inverse of input static nonlinearity that is utilized to form an approximate linear model of the Hammerstein system. Based on the established model, a model predictive controller under predefined speed and acceleration constraints is designed to achieve safer treadmill exercise. Simulation results show that the proposed control algorithm can achieve optimal heart rate tracking performance under predefined constraints.

Identification and Control for Heart Rate Regulation During Treadmill Exercise

This paper proposes a novel integrated approach for the identification and control of Hammerstein systems to achieve desired heart rate profile tracking performance for an automated treadmill system. For the identification of Hammerstein systems, the pseudorandom binary sequence input is employed to decouple the identification of dynamic linear part from input nonlinearity. The powerful epsilon-insensitivity support vector regression method is adopted to obtain sparse representations of the inverse of static nonlinearity in order to obtain an approximate linear model of the Hammerstein system. An Hinfinity controller is designed for the approximated linear model to achieve robust tracking performance. This new approach is successfully applied to the design of a computer-controlled treadmill system for the regulation of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed of the treadmill. Both conventional proportional-integral-derivative (PID) control and the proposed approaches have been employed for the controller design. The proposed algorithm achieves much better heart rate tracking performance.

Heart rate control during treadmill exercise

A computer-controlled treadmill and related data collection and processing systems have been developed for the control of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed and/or the gradient of the treadmill. A simple and practical heart rate measurement algorithm has been developed to robustly measure the variations of heart rate. Both conventional Proportional-Integral-Derivative (PID) control and fuzzy Proportional-Integral (PI) control approaches have been employed for the controller design. The fuzzy Proportional-Integral algorithm achieved better heart rate tracking performance. Finally, a heart rate based exercising protocol was successfully implemented on the newly designed exercise system.

Mechanical energy and power flow of the upper extremity in manual wheelchair propulsion

OBJECTIVE

To investigate the characteristics of mechanical energy and power flow of the upper limb during wheelchair propulsion.

DESIGN

Mechanical energy and power flow of segments were calculated.

BACKGROUND

Very few studies have taken into account the mechanical energy and power flow of the musculoskeletal system during wheelchair propulsion. Mechanical energy and power flow have proven to be useful tools for investigating locomotion disorders during human gait.

METHODS

Twelve healthy male adults (mean age, 23.5 years) were recruited for this study. Three-dimensional kinematic and kinetic data of the upper extremity were collected during wheelchair propulsion using a Hi-Res Expert Vision system and an instrumented wheel, respectively.

RESULTS

During the initiation of the propulsion phase, joint power is generated in the upper arm or is transferred from the trunk downward to the forearm and hand to propel the wheel forward. During terminal propulsion, joint power is transferred upward to the trunk from the forearm and upper arm. The rate of change of mechanical energy and power flow for the forearm and hand have similar patterns, but the upper arm values differ.

CONCLUSIONS

Joint power plays an important role in energy transfer as well as the energy generated and absorbed by muscles spanning the joints during wheelchair propulsion.

RELEVANCE

Energy and power flow information during wheelchair propulsion allows us to gain a better understanding of the coordination of the movement by the musculoskeletal system.

The pediatric athlete with disabilities

There have been increased opportunities and sports participation by athletes with disabilities during the past decades. Research on pediatric athletes with disabilities remains limited. Appropriate classification of athletes on the basis of their functional abilities is key to fair participation. Preparticipation evaluation of these athletes is based on similar principles as for able-bodied athletes. The prevalence, nature, evaluation, differential diagnosis, and treatment principles for injuries are similar for athletes with disability and for those without. There are few disability-specific medical and orthopedic issues to be considered in working with these athletes. Sport participation recommendations are based on the specific disability and demands of the sport. The vast majority of athletes with disabilities can participate safely in a number of sports if appropriately matched; such participation should be encouraged and facilitated at all levels because of well-recognized psychological and medical benefits. Significant progress has been made in increasing sports participation opportunities for persons with disabilities; this is especially true for adults and, to a lesser extent, for children and adolescents. Many barriers remain, however: inadequate facilities, exclusion of children with disabilities, medical professional overprotection, lack of trained personnel and volunteers to work with children with disabilities, lack of public knowledge about disabilities, and lack of financial support for sport and physical education in schools [9,12].

Physiological responses to two wheelchair-racing exercise protocols

OBJECTIVE

This study investigated the blood lactate accumulation during two wheelchair-racing protocols. During exercise, energy is required, which causes metabolism to increase and blood lactate to accumulate. Proper training can reduce the amount of blood lactate accumulation and increase tolerance to blood lactate accumulation during aerobic exercise.

METHODS

Eleven male wheelchair elite track athletes with a spinal cord injury were tested to determine their blood lactate response to speed and resistance workouts. A computer-monitored wheelchair dynamometer was used during all exercise tests. The order of the test (e.g., speed or resistance workout) was randomized. Blood pressure and blood samples were taken immediately before and after completion of each exercise test.

RESULTS

The difference between the blood lactate concentrations before and after testing were 8.56 +/- 4.42, and 11.67 +/- 4.69 mM for the resistance and speed tests, respectively.

CONCLUSIONS

Our results showed that the blood lactate responses were significantly different for the resistance and speed workouts.

Aerobic work capacity in elite wheelchair athletes: a cross-sectional analysis

OBJECTIVE

To give a descriptive analysis of aerobic capacity among elite wheelchair athletes in association with various personal characteristics and sprint or anaerobic capacity.

DESIGN

Sixty-eight wheelchair athletes who participated in the World Games and Championships for the Disabled were included. Parameters for aerobic capacity were evaluated in a standardized wheelchair exercise test on a computer-controlled wheelchair ergometer at the games. The ergometer setting was individually tuned according to standardized procedures.

RESULTS

Mean maximum power output was 72.2 +/- 36.7 W. Peak oxygen uptake showed similar strong variations among different subject groups. High values were seen in a group of six subjects with amputations. Results stressed that, apart from sex, functionality and training status had a strong influence on aerobic capacity. Anaerobic and aerobic capacity were strongly associated.

CONCLUSIONS

Functionality, training status, and sex are important determinants of aerobic capacity. The functional classification used at international sports events is represented in the data, and further study into the possible contribution of standardized exercise tests within the issue of classification must be considered. The use of standardized exercise tests for the evaluation of training and for rehabilitation progress must be advocated, with power output being an important outcome measure at the level of ability, whereas oxygen uptake represents outcome at the level of organ systems.

Physiology of wheelchair racing in athletes with spinal cord injury

Wheelchair racing is one of the most popular sporting activities of individuals with spinal cord injury. Athletes with this impairment have unique changes in metabolic, cardiorespiratory, neuromuscular and thermoregulatory systems, which reduce their overall physiological capacity compared with able-bodied individuals or individuals with other types of impairments. This review on spinal cord injury: presents the International Stoke Mandeville Games Federation classification of wheelchair athletes; describes methods commonly used to characterise anaerobic and aerobic fitness; presents the findings of physiological studies that have evaluated wheelchair racing performance; identifies the risks associated with temperature regulation when competing in wheelchair races; and discusses special conditions that can influence wheelchair racing performance. Currently there is limited research that has examined the relationship between sprint or distance wheelchair racing performance and the anaerobic and aerobic components of physical fitness. Although the descriptive evidence indicates that the profiles of these athletes reflect their training and participation in these specific events, the association between their physiological profiles and real or simulated racing performance is unclear. The generally accepted concept that high values of aerobic and anaerobic power are strongly correlated with endurance and sprint racing performance, respectively, are not necessarily true in this population. Athletes with spinal cord injury have an impaired thermoregulatory capacity, because the compromised autonomic and somatic nervous system functions disrupt control of skin blood flow and sweating below the level of the lesion. As a result, they may be more susceptible to hyperthermia during distance wheelchair racing performance. Wheelchair athletes should follow recommendations advocated for able-bodied individuals to minimise their risks of heat stress during competition. Many athletes with quadriplegia voluntarily induce autonomic dysreflexia (commonly known as boosting) during distance racing events to improve performance. Experimental evidence indicates that boosting can improve performance time by 10% in elite wheelchair marathon racers during simulated racing, as a result of increased oxygen utilisation in the boosted state. However, since boosting can be dangerous to health, the International Paralympic Committee has banned athletes from voluntarily inducing it during competition. The use of anti-gravity suits to increase lower-body positive pressure can increase the peak oxygen uptake, cardiac output and stroke volume. However, the use of abdominal binders does not influence these physiological responses. An effect of either of these techniques on wheelchair racing performance has not been demonstrated.