A treadmill is a piece of indoor sporting equipment used to allow for the motions of 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 (see treadwheel.)
The principle is a belt system (an electric motor or flywheel connected to a circular run of material) where the top of the belt moves to the rear so as to allow a runner to run an equal, and necessarily opposite speed. Thus the speed of the run can easily be set or measured (the rate at which the belt moves is the rate at which the runner moves). The more expensive, heavy-duty versions are motor-driven. The simpler, lighter, cheaper versions are passive, moving only when the walker pushes the belt with their feet, and operates just to resist the motion.
Treadmills were historically used as a method of reforming offenders in prison, an innovation introduced by Sir William Cubitt
in 1817.; these were also termed treadwheels
. The first private health club in the U.S. was started by Professor Louis Attila in 1894. Cardio workout machines entered the clubs much later and were developed initially for the hospital. The first medical treadmill designed to diagnose heart and lung disease was invented by Dr. Robert Bruce
and Wayne Quinton at the University of Washington in 1952. Dr. Kenneth Cooper's
research on the benefits of aerobic exercise, published in 1968, provided a medical argument to support the commercial development of the home treadmill and exercise bike.
As a cardiovascular exercise:
- Running or walking on a treadmill can be an effective way to work out, like other complex cardiovascular exercises (similar to non-treadmill walking/running). As with all exercise, regular treadmill use increases endurance.
- Treadmills offer the benefit of reduced impact since all treadmills offer some sort of shock absorption. Exercising on a treadmill can reduce the strain to the ankles, knees and lower back of users.
As an indoor activity:
- Users who would not run/walk outdoors (e.g. due to unfavourable weather conditions, uneven road surfaces, dangerous neighbourhoods or unwanted attention) may use an indoor treadmill.
- Users who do not wish to join a gym may use an indoor treadmill at home.
- Users can do other things while exercising, such as watching television or reading.
As a machine:
- Enables exact calculation and adjustment of slope and speed.
- As most of the factors of the activity are known, the energy expended may be calculated.
- Some treadmills have special features such as step count, heart rate monitors, amount of calories expended.
- Many users find treadmills boring and lose interest after a period.
- Cost of purchase and electricity to run the treadmill is significantly greater than running outside.
- Takes up space in homes (disadvantage reduced by "folding treadmill" option).
- May cause personal injury if not used properly.
- Can make a loud grinding noise if the belt keeps slipping.
- Lack of wind resistance makes running on a treadmill easier than it would otherwise be on an equal elevation grade outdoors. Training for outdoor races is complicated due to the subtle differences.
- There is little need to propel yourself on a treadmill, making running easier and therefore not giving you an accurate representation of running on the ground. This can be a disadvantage when training for outdoor races.
- Ordinary treadmills, even the expensive models at gyms and clubs, are not usually able to tilt at the steep slopes used on medical treadmills for standardized stress tests.
- Imposes a strict pace on runners, giving an unnatural feel to running which can cause a runner to lose balance.
- As with all forms of cardiovascular exercise, the risk of cardiac arrest is significantly increased. Treadmills may further this risk, as indoor comforts, such as air conditioning, may cause a user to feel more comfortable and less likely to stop due to exhaustion.
As it is basically a conveyor belt
, the treadmill can be used for activities other than running. If horses
are being tested (especially in jockey racing) they will be put on a specially constructed treadmill. Large treadmills can also accommodate cars.
Advanced applications are so called omnidirectional treadmills. They are designed to move in two dimensions and are intended as the base for a "holodeck". There are several solutions which were proposed and research continues because some issues remain unsolved until now such as large size, noise and vibration.