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The purpose of this study was to design and validate an instrumented wheel system (IWS) that can measure 3-dimensional (3-D) pushrim forces during racing wheelchair propulsion. Linearity, precision, and percent error were determined for both static and dynamic conditions. For the static condition, the IWS demonstrated a high linearity (0.91 <or= sl...
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Citations
... Other systems are based on force transducers, e.g., one 3-DOF [11] or four 2-DOF [12] transducers. ...
Wheelchair propulsion and actuation are influenced by the moving masses of the wheelchair user; however, the extent of this effect is still unclear. The main evidence of this effect is that the speed of the wheelchair frame continues to increase after the end of the push phase. The wheel-chair's speed was measured using IMUs and the duration of the push period was recorded using miniaturised pressure sensors attached to the driver's middle fingers. The velocity and acceleration were determined for various average stroke cycle speeds to determine the speed dependency of the acceleration. The wheelchair was then mounted on a force plate to measure the inertial forces of the hands moving back and forth. The aerodynamic drag and rolling resistance forces were determined from coast-down experiments. Based on the measured forces, the behaviour of the force and velocity profiles was finally modelled by gradually reducing the mass of the arms and thus their inertial force. The results showed that the wheelchair is accelerated throughout the push phase (except for a temporary deceleration in the middle of the push phase at higher velocities), and that this acceleration continues well after the push phase. In the second half of the recovery phase, the wheelchair decelerates. The horizontal inertial forces measured on the force plate are predominantly negative in the push phase and in the second half of the recovery phase, and positive in the first half of the push phase, and their impulse is zero due to the conservation of momentum. Modelling the wheelchair with moving masses showed that reducing the horizontal inertial forces has no effect on the driver's propulsive force but reduces the velocity fluctuations. The main conclusion of this research is that the wheelchair user's power should be calculated only from the pure propulsive force that is required in the push phase to overcome the dissipative forces and that enables the gain or loss in speed per stroke cycle, but not directly from the measured velocity.
... To support this effort, wheelchair wheels have been instrumented with force sensors. [10][11][12][13][14][15][16][17][18][19] Most notably, the SMART Wheel12 and, later, the Optipush 18 systems have provided 3D kinetic data in many studies over the last 20 years, but since these are no longer commercially available, access to knowledge on the functional loading conditions in the upper extremities during dynamic activities has been limited to research developments. ...
... A recurring principle in the design of such measurement wheels is separating the push-rim from the wheel-rim and directly mounting it to the hub via an optimally rigid sensor unit. In some cases, off-the-shelf 3D force transducers have been used, 11,15 while others have applied strain gauges directly to solid metal spokes connecting the push-rim to the wheel hubs. 10,13,16 More recently, Miyazaki and colleagues used four 2D load cells between a sports push-rim and a disc-shaped adapter plate to allow the measurement unit to be mounted to different sports wheelchair wheels as desired. ...
... Finally, previous authors have presented static measurements as a baseline validation for their measurement instruments. 15,17,19 While methodically comparable in that respect, the lack of dynamic validation measurements is a clear limitation of this project at this stage. Towards improving validity, future developments should identify methods that are able to mimic the dynamic, cyclic characteristics of wheelchair propulsion in a controlled and repeatable manner for validation and to ultimately pave the way for functional measurements in real life settings. ...
Introduction
Force measurement wheels are essential instruments for analysing manual wheelchair propulsion. Existing solutions are heavy and bulky, influence propulsion biomechanics, and are limited to confined laboratory environments. In this paper, a novel design for a compact and lightweight measurement wheel is presented and statically validated.
Methods
Four connectors between the push-rim and wheel-rim doubled as force sensors to allow the calculation of tangential and radial forces as well as the point of force application. For validation, increasing weights were hung on the push-rim at known positions. Resulting values were compared against pre-determined force components.
Results
The implemented prototype weighed 2.1 kg and was able to transmit signals to a mobile recording device at 140 Hz. Errors in forces at locations of propulsive pushes were in the range up to ±3.1 N but higher at the frontal extreme. Tangential force components were most accurate.
Conclusion
The principle of instrumenting the joints between push-rim and wheel-rim shows promise for assessing wheelchair propulsion in daily life.
... In contrast to everyday propulsion, two of the three racing studies reported negative lat-255 eral forces but with inconsistent force profiles. The positive lateral forces reported by Limroongreungrat et al. were attributed to differences in wheelchair design and propulsion speed (41) . ...
... In an early study on wheelchair propulsion, video recording based on a single camera was used for kinematic analysis, but accurate and complex analysis was only achieved when a motion analysis system was applied using multiple cameras. 1 For the kinetic study of wheelchair propulsion, instrumented wheel systems (IWSs) that can measure triaxial forces and torques applied to the handrim have been adopted. [2][3][4][5] Cooper 2 developed the first SMART Wheel capable of measuring forces along the three axes. This device has been recently improved for wireless, indoor data collection from up to 300 ft by using Wi-Fi communication. ...
... The maximum error in static torque measurements is 1.95%, and dynamic tests using axle torques are highly correlated with the expected values (r > 0:98). These results are comparable with those reported by Limroongreungrat et al. 3 and Guo et al. 4 In future work, we will conduct clinical research using the developed IWS. In addition, we will combine the IWS with a motion analysis system to perform further research on manual wheelchairs. ...
The purpose of this study was to design and validate a new bilateral instrumented wheel system (IWS) to measure triaxial handrim forces and torques simultaneously during the wheelchair propulsion. The designed and implemented system measures the force applied to the handrims on both sides of a manual wheelchair using 6-axis force/torque sensors. In addition, a user interface receives the measurements from the left and right IWSs. To verify the accuracy of the wheel system, we evaluate force and torque measurements during the static and dynamic tests. The maximum error in static measurements of force and torque are 4.29% and 1.95%, respectively. Likewise, dynamic tests using planar forces and axle torques provide low errors and measurements that are highly correlated with the expected values ([Formula: see text]). The results revealed that the proposed IWS can be used to measure bilateral 3D handrim reaction forces with acceptable accuracy.
... However, results for only one athlete have been reported, and no analysis of the differences between push-rim force characteristics for multiple athletes has been conducted. 11 In addition, Rice et al. reported the effect of using different glove types on the push-rim force by measuring the 3D push-rim force on the wheel. However, the relation between propulsive style for various athletes and push-rim force has not been examined. ...
... Goosey-Tolfrey et al. 11 reported tangential forces on the push-rim for 10 participants using an originally developed force sensor system. The mean peak tangential force of six participants reported in the paper was 158 N for a traveling speed of 5.64 m/s. ...
... The mean peak tangential force of six participants reported in the paper was 158 N for a traveling speed of 5.64 m/s. 11 The results of this study showed that the mean peak value for a traveling speed of 5.56 m/s for three participants was 131 N, similar to their results. According to their research, all but one participant followed similar patterns, with the peak force occurring between 140 and 180°, which is similar to the patterns of participants 2 and 3 in this study. ...
To improve competitive skills, it is important to clarify the relationship between the propulsion motion (the propulsive force in the use of racing wheelchairs optimized for athletes) and aerodynamic drag, which can change during propulsive motion. Therefore, the purpose of this research was to construct a novel force sensor system that is attachable to racing wheelchairs for individual athletes and usable in a wind tunnel facility to examine differences in the push-rim force characteristics of athletes based on the measured results. The system was composed of four two-dimensional component force sensors, batteries, and radio transmitters. From the output of the four two-dimensional component sensors, tangential and radial components of the push-rim force were measured. Three top-class long-distance wheelchair athletes participated in this study, which required each athlete to push a racing wheelchair at 5.56 m/s on a wheelchair roller system in a wind tunnel facility. The force sensor system was mounted on the participants’ individual racing wheelchairs. The measured tangential force waveforms were classified as either bimodal or unimodal depending on the athletes’ propulsion styles. Although two athletes showed similar propulsion style characteristics, the athlete with more years of experience showed better propulsive work efficiency and repeatability. Therefore, a difference in skill for applying propulsive force during the push phase, which is difficult to estimate by kinematic analysis, could be estimated by using the force sensor system.
... force croisés avec les cycles, phases et angles de poussée permettent aujourd'hui de mieux comprendre la biomécanique de cette activité. Quelques constatations non exhaustives : 1) les centres de pression (points virtuels de l'application de la force) ne sont pas nécessairement localisés dans l'axe projeté de la main (Cooper, 1995); 2) les moments à l'épaule sont plus grands que ceux du coude ou du poignet (Robertson et al., 1996); 3) les utilisateurs de FRC adoptent une stratégie de propulsion différente des utilisateurs de FR conventionnels et les forces de propulsion augmentent proportionnellement avec la vitesse de déplacement (Goosey-Tolfrey, V. L. et al., 2001); 4) les utilisateurs de FR conventionnels sont moins sujets à développer des TMS si la vitesse de la main au moment de l'impact sur la MC correspond plus étroitement à la vitesse de la roue (Yang, 2003); 5) l'application de la force radiale sur la MC d'un FRC, qui est nécessaire au maintien du contact entre le gant et le cerceau en raison du frottement, est très importante, soit deux fois supérieures à la force tangentielle et presque quatre fois supérieures à la force axiale (Limroongreungrat et al., 2009 Parmi les différentes approches en ergonomie, l'analyse de l'activité demeure la plus pertinente pour répondre aux enjeux de cette recherche. L'utilisateur, l'athlète, est au centre de cette analyse. ...
... To study the biomechanics of wheelchair propulsion, researchers and clinicians have used instrumented wheels with force-sensing push-rims. [1][2][3] These instrumented wheels show accuracy in measuring forces, 4,5 and recently demonstrated reliability while documenting the minimal detectable change. 6 Due to their design and measurement requirements, instrumented wheels have a greater mass compared with regular wheelchair wheels. ...
Background:
Instrumented wheelchair wheels can be used to study the kinematics and kinetics of manual wheelchair propulsion. The objective of this study was to evaluate the impact of instrumented wheels on the inertial and frictional parameters of a wheelchair system.
Methods:
This study compared mechanical parameters of an ultralightweight rigid frame wheelchair configured with pairs of SMARTwheels and spoke pneumatic wheels and loaded with an ISO 75 kg wheelchair dummy. Rectilinear and turning inertia of the occupied wheelchair and the rotational inertia of drive wheels were measured. A coast-down test measured frictional energy loss during straight and turning trajectories.
Findings:
The addition of instrumented wheels increased occupied system mass by about 6% and turning inertia by about 16%. Frictional energy loss increased by over 40% in a straight trajectory and over 30% during turning.
Interpretation:
Addition of instrumented increased the inertia and frictional energy loss of the wheelchair system. These relative effects will impact the wheelchair operator and increase the instantaneous propulsion torque during wheelchair maneuvers. The impacts will be less under conditions involving little or no change in velocity. Researchers should be encouraged to report changes in mass and weight distribution induced by addition of instrumented wheelchair wheels.
... N-m in the plane of the handrim, and about 3.40 N and 0.25 N-m in the wheel axle direction, respectively. Limroongreungrat et al. [44] presented an attempt to design and validate an IWS using a commercial force transducer (Model 45E15A-U760, JR-3, Inc., Woodland, CA) to measure three-dimensional pushrim forces of wheelchair propulsion in a racing wheelchair. Linearity, precision, and percent error were determined for both static and dynamic conditions. ...
The repetitious nature of propelling a wheelchair has been associated with the high incidence of injury among manual wheelchair users (MWUs), mainly in the shoulder, elbow and wrist. Recent literature has found a link between handrim biomechanics and risk of injury to the upper extremity. The valid measurement of three-dimensional net joint forces and torques, however, can lead to a better understanding of the mechanisms of injury, the development of prevention techniques, and the reduction of serious injuries to the joints. In this project, an instrumented wheel system was developed to measure the applied loads dynamically by the hand of the user and the angular position of the wheelchair user's hand on the handrim during the propulsion phase. The system is composed of an experimental six-axis load cell, and a wireless eight channel data logger mounted on a wheel hub. The angular position of the wheel is measured by an absolute magnetic encoder. The angular position of the wheelchair user's hand on the handrim during the propulsion phase (ɸ) or point of force application (PFA) is calculated by means of a new-experimental method using 36 pairs of infrared emitter/receiver diodes mounted around the handrim. In this regard, the observed data extracted from an inexperienced able-bodied subject pushed a wheelchair with the instrumented handrim are presented to show the output behavior of the instrumented handrim. The recorded forces and torques were in agreement with previously reported magnitudes. However, this paper can provide readers with some technical insights into possible solutions for measuring the manual wheelchair propulsion biomechanical data.
... From a scientific point of view this provides a deeper understanding of the universal principles regarding the motor control of wheelchair propulsion, while from a clinical perspective it can help to better tailor the properties of a wheelchair to a patients needs' and develop intervention protocols with respect to propulsion technique and strategy [11]. Over time, different studies have used different ways to instrument the wheels to gain insight in the forces and timing involved in wheelchair propulsion, varying from instrumented ergometers to specialized wheels [9,10,1213141516. These measurement systems have been used to describe unilaterally the cyclic nature of handrim propulsion analogous to gait analysis. ...
Background
Handrim wheelchair propulsion is a complex bimanual motor task. The bimanually applied forces on the rims determine the speed and direction of locomotion. Measurements of forces and torques on the handrim are important to study status and change of propulsion technique (and consequently mechanical strain) due to processes of learning, training or the wheelchair configuration. The purpose of this study was to compare the simultaneous outcomes of two different measurement-wheels attached to the different sides of the wheelchair, to determine measurement consistency within and between these wheels given the expected inter- and intra-limb variability as a consequence of motor control.
Methods
Nine able-bodied subjects received a three-week low-intensity handrim wheelchair practice intervention. They then performed three four-minute trials of wheelchair propulsion in an instrumented hand rim wheelchair on a motor-driven treadmill at a fixed belt speed. The two measurement-wheels on each side of the wheelchair measured forces and torques of one of the two upper limbs, which simultaneously perform the push action over time. The resulting data were compared as direct output using cross-correlation on the torque around the wheel-axle. Calculated push characteristics such as power production and speed were compared using an intra-class correlation.
Results
Measured torque around the wheel axle of the two measurement-wheels had a high average cross-correlation of 0.98 (std=0.01). Unilateral mean power output over a minute was found to have an intra-class correlation of 0.89 between the wheels. Although the difference over the pushes between left and right power output had a high variability, the mean difference between the measurement-wheels was low at 0.03 W (std=1.60). Other push characteristics showed even higher ICC’s (>0.9).
Conclusions
A good agreement between both measurement-wheels was found at the level of the power output. This indicates a high comparability of the measurement-wheels for the different propulsion parameters. Data from both wheels seem suitable to be used together or interchangeably in experiments on motor control and wheelchair propulsion performance. A high variability in forces and timing between the left and right side were found during the execution of this bimanual task, reflecting the human motor control process.
... The last decade also instrumented racing wheels have been developed. A 2-dimensional system was developed by Goosey-Tolfrey et al. 77 , a 3dimensional wheel by Limroongreungrat and coworkers 109 . ...
... This limitation origins from practical limitations since it was impossible to apply perfectly tangential or radial forces to the handbike system. Even Limroongreungrat et al. 109 who tested a sports wheel reported only on the force in the propulsion plane and the lateral force. Further, the applied forces were rather low but applying higher forces on the stationary system was not possible. ...
... Of the commercially available systems the SmartWheel is used most often, however not all systems are tested in the same extent. Details on the linearity are only available for the systems of Asato et al. 36 , Wu et al. 223 , Limroongreungrat et al. 109 and ...
Handbikes come in different models and setups, but only limited knowledge is available on the handbike-user interface. The aim of this study was to identify optimal handbike setups, assuming that in such a setup mechanical efficiency is high, while shoulder load is low. Thirteen subjects with a spinal cord injury (paraplegia) performed handcycling with different handbike setups at constant power output: four crank positions (two distances, two heights) and four backrest inclinations. The O(2) -consumption, kinetics, and kinematics were measured to calculate mechanical efficiency and shoulder load (glenohumeral contact force, net shoulder moments, and rotator cuff force). The analysis showed that more upright backrest positions resulted in lower shoulder load compared with the most reclined position [glenohumeral contact force (260 vs 335 N), supraspinatus (14.4% vs 18.2%), and infraspinatus force (5.4% vs 9.8%)], while there was no difference in efficiency. Except for a reduction in subscapularis force at the distant position, no differences in shoulder load or efficiency were found between crank positions. Recreational handbike users, who want to improve their physical capacity in a shoulder-friendly way, should set up their handbike with a more upright backrest position and a distant crank placement.
