Turbo trainer

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A turbo trainer is any device used to convert a road bicycle to a stationary exercise bicycle, by mounting the cycle in a rigid framework. This distinguishes turbo trainers from rollers which likewise permit a bicycle to be used without moving, but which allow the cycle to sway in a similar manner to when moving on a road. Turbo trainers all provide a framework which makes the bicycle stable to sit on and pedal while stationary and some sort of mechanism to provide resistance to pedalling. More sophisticated examples provide a greater degree of control and precision to the user and a variety of feedback, particularly in modern computerised devices.

[edit] Turbo trainer resistance mechanisms

Turbo trainers apply several different physical principles to produce rolling resistance comparable to the total resistance to tbe motion of a cycle on the road (which is mainly due to air resistance and slope).

The simplest examples use an adjustable frictional resistance, which may be a robust band, which may be tightened by the user prior to exercise, pressing against a cylinder rotated by the back wheel of the bicycle. Other examples use a gearing mechanism to drive a large fan which takes a considerable amount of power to turn at speed, and which can be used to provide useful cooling for the user to replace the movement through air on the road. Some modern turbo trainers drive a small fan in an enclosed fluid, which provides a large and quite precise resistance to rotation in a compact device. Others use a magnetic resistance system, based on the dynamo effect. These have the advantage of allowing electrical calibration and a wide range of precise control through increasing the current passing through one of the coils.

[edit] Input and output

Most turbo trainers provide a mechanism for adjusting resistance, although in the simpler devices this may only be adjusted prior to a session. However, in the large majority of designs, the resistance changes as the gears are changed on the bicycle, which allows a high degree of user control of resistance during a session.

Some modern turbo trainers incorporate a simple built-in computer which caters for a variety of user input and output. These may provide calibration of the resistance, control of resistance to emulate hills (under the control of the user or a pre-programmed schedule), measurements of mechanical power, inferred speed, pedalling cadence, heart rate (via a radio interface from a chest band) and even torque on the most sophisticated models. In addition derived statistics including integrals and averages of these statistics are commonly available. Some designs provide an interface to a standard personal computer, which allows more sophisticated processing and graphing of data.

[edit] Applications

Turbo trainers are used as a training aid by many competitive cyclists, allowing precisely controlled and monitored exercise regardless of weather and road conditions. With the wide availability of increasingly economical and sophisticated devices, turbo trainers are beginning to become a more popular exercise device for cyclists at all levels, including those who do not participate in road races. One advantage of turbo trainers over exercise bicycles is that the device itself is compact and easily stored, and a road cycle can be mounted in it for an indoor exercise session or removed for use on the road in a matter of seconds.