Wheelchair Trainer
A wheelchair trainer or wheelchair treadmill is an apparatus that allows a manual wheelchair
A wheelchair is a chair with wheels, designed to be a replacement for walking. The device comes in variations where it is propelled by motors or by the seated occupant turning the rear wheels by hand. Often there are handles behind the seat for someone else to do the pushing...

 user to simulate linear (translational) travel while remaining stationary in a manner similar to an ambulatory person walking or running on a treadmill
A treadmill is an exercise machine for running or walking while staying in one place. The word treadmill traditionally refers to a type of mill which was operated by a person or animal treading steps of a wheel to grind grain...

 or a cyclist pedaling a bicycle on a bicycle trainer
Bicycle trainer
A trainer, or turbo trainer, is a piece of equipment that makes it possible to ride a bicycle while it remains stationary. They are commonly used to train for races, or when riding conditions outside are not favorable...

. The rear wheelchair wheels are placed in contact with vertical or horizontal rollers which may also be attached to flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...

s, mechanical resistance or braking mechanisms, motors and various speed and force sensors. Flywheels may be sized to provide a user of a certain mass with a rotational inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...

 equivalent to their translational (linear) inertia in order to more realistically approximate actual wheelchair propulsion.

Wheelchair trainers having independent contact rollers permit simulated directional travel (omnidirectional treadmill
Omnidirectional treadmill
An omnidirectional treadmill, or ODT, is a device that allows a person to perform locomotive motion in any direction. The ability to move in any direction is how these treadmills differ from their basic counterparts...

). Trainers may also incorporate rotary encoder
Rotary encoder
A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position or motion of a shaft or axle to an analog or digital code. The output of incremental encoders provides information about the motion of the shaft which is typically further processed...

s, accelerometer
An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...

s and torque sensor
Torque sensor
A torque sensor or torque transducer or torquemeter is a device for measuring and recording the torque on a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, or a bicycle crank. Static torque is relatively easy to measure...

s to enable interface with computer data acquisition
Data acquisition
Data acquisition is the process of sampling signals that measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems typically convert analog waveforms into digital values for processing...

 systems (DAQ) for analysis of propulsion kinematics
Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....

. A quadrature rotary encoder or hall effect sensor
Hall effect sensor
A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing applications....

 can be implemented to provide sufficient speed and direction information to enable virtual navigation interface with video games in a manner similar to using a joystick
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...

 or gaming console
Video game console
A video game console is an interactive entertainment computer or customized computer system that produces a video display signal which can be used with a display device to display a video game...

. Calculation of rolling resistance
Rolling resistance
Rolling resistance, sometimes called rolling friction or rolling drag, is the resistance that occurs when a round object such as a ball or tire rolls on a flat surface, in steady velocity straight line motion. It is caused mainly by the deformation of the object, the deformation of the surface, or...

 between the tire & contact roller interface, axle friction, and inertial characteristics of wheelchair wheels and flywheels may be used in determination of stationary propulsion dynamics
Dynamics may refer to:-Physics and engineering:* Dynamics , the time evolution of physical processes** Aerodynamics, the study of gases in motion...



The United States Department of Veterans Affairs
United States Department of Veterans Affairs
The United States Department of Veterans Affairs is a government-run military veteran benefit system with Cabinet-level status. It is the United States government’s second largest department, after the United States Department of Defense...

 (VA) has substantially invested in decades long research and development for two wheelchair trainer devices: the Wheelchair Aerobic Fitness Trainer (WAFT), and GameWheels. The history of wheelchair trainer development may be summarized from the 10 patents issued by the United States Patent and Trademark Office
United States Patent and Trademark Office
The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...

 for stationary wheelchair trainers/treadmills/ergometers/dynamometer
A dynamometer or "dyno" for short, is a device for measuring force, moment of force , or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed .A dynamometer can also be used to determine...

/simulators issued from 1980 to 2009.
US Patent Number Issue Date Key Features
4,233,844 November 18, 1980 introduces variable inertial flywheels to approximate user mass with speed & torque sensors
4,911,425 March 27, 1990 WAFT (early model) implements independent adjustable wheel resistance
4,966,362 October 30, 1990 incorporates forward or reverse unidirectional wheel rotation
5,476,429 December 19, 1995 WAFT (later model) introduces cardio exercise with active electrical controls,DAQ and video gaming interface
5,643,143 July 1, 1997 implements positioning over two rollers
5,649,883 July 22, 1997 minimizes rolling resistance for 3 wheeled wheelchair race chairs
5,704,876 January 6, 1998 implements bicycle trainer eddy current braking resistance and active computer control interface
5,709,631 January 20, 1998 implements lateral wheel guides to prevent side sway
6,113,519 September 5, 2000 utilizes electrically controlled resistance and camber adjustment for clinical applications
7,604,572 October 20, 2009 implements horizontal rollers with passive variable inertia & resistance, clinical DAQ and video gaming interface


The last patent is being commercialized under the trademark Trekease, designed to serve as an acronym for Translational & Rotational Equivalent Kinetic Energy Aerobic Stationary Exertainment and as a homonym for Trekkies
Trekkies is a 1997 documentary film directed by Roger Nygard about the devoted fans of Gene Roddenberry's Star Trek franchise. Starring Denise Crosby , the movie contains interviews with Star Trek devotees, more commonly known as Trekkies...

 – fans of Star Trek
Star Trek
Star Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...

. None of the other cited patents, including the experimental prototypes developed by the VA, are currently being commercialized; however simple unidirectional ramp and roller systems similar in design to patent #4,966,362 are being marketed by others. (See also External links).

Arcade game
Arcade game
An arcade game is a coin-operated entertainment machine, usually installed in public businesses such as restaurants, bars, and amusement arcades. Most arcade games are video games, pinball machines, electro-mechanical games, redemption games, and merchandisers...

 software and clinical data acquisition use were first introduced by the Veterans Administration's WAFT as a means of promoting stationary wheelchair propulsion as a beneficial aerobic exercise
Aerobic exercise
Aerobic exercise is physical exercise of relatively low intensity that depends primarily on the aerobic energy-generating process. Aerobic literally means "living in air", and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism...

. Clinical professionals are not currently in agreement regarding the cardiovascular health benefits associated with manual wheelchair propulsion and the possible long term repetitive use injuries attributed to manual wheelchair operation.[aerobics] These debates have encouraged developments to enhance wheelchair seating, back support, frame, wheel, and hand-rim designs.[mechanics] Innovative lever styled mechanisms add a new level to improve the overall efficiency, posture and ergonomics of manual wheelchair propulsion.[ergonomics] Utilizing lever propulsion technologies on a wheelchair trainer equipped with flywheel and resistance enables one to engage in an activity similar to rowing
Rowing (sport)
Rowing is a sport in which athletes race against each other on rivers, on lakes or on the ocean, depending upon the type of race and the discipline. The boats are propelled by the reaction forces on the oar blades as they are pushed against the water...

with all its associated health benefits and risks.


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External links

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