Treadmill

For historic usage, see Treadwheel.

For other uses, see Treadmill (disambiguation).

A woman on a treadmill

A treadmill is a device for walking while staying in the same place. Treadmills were introduced before the development of powered machines, to harness the power of animals or humans to do work, often a type of mill that was operated by a person or animal treading steps of a treadwheel to grind grain. In later times treadmills were used as punishment devices for people sentenced to hard labour in prisons. The terms treadmill and treadwheel were used interchangeably for the power and punishment mechanisms.

More recently treadmills are not used to harness power, but as exercise machines for running or walking in one place. Rather than the user powering the mill, the machine provides a moving platform with a wide conveyor belt driven by an electric motor or a flywheel. The belt moves to the rear requiring the user to walk or run at a speed matching that of the belt. The rate at which the belt moves is the rate of walking or running. Thus, the speed of running may be controlled and measured. The more expensive, heavy-duty versions are motor-driven (usually by an electric motor). The simpler, lighter, and less expensive versions passively resist the motion, moving only when walkers push the belt with their feet. The latter are known as manual treadmills.

Treadmills for power

Treadmills as power sources originated in antiquity. Typically they rotate around a vertical axis, driven by an ox walking in a circle.

Treadmills for punishment

Treadmills for punishment usually rotate around a horizontal axis, requiring the user to step upwards, like walking up a never-ending staircase. Those punished are outside the wheel. Small similar horizontal-axis treadmills but with a single occupant inside are familiar toys for small pet animals such as hamsters. This type of treadmill is often called a treadwheel.

Treadmills were used in prisons in Britain from 1818; they were like twenty-foot long paddle wheels with twenty-four steps around a six-foot cylinder. Several prisoners stood side-by-side on a wheel, and had to work six or more hours a day, effectively climbing 5,000 to 14,000 vertical feet. While the purpose was mainly punitive, the mill could grind grain, pump water, or ventilate.

Exercise treadmills

The forerunner of exercise treadmills was designed to diagnose heart and lung disease, and was invented by Dr. Robert Bruce and Wayne Quinton at the University of Washington in 1952^{[citation needed]}. Dr. Kenneth H. 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.

The treadmill test at the medical centre of the Olympic village during the 1980 Summer Olympics. RIAN photo.

Among the users of treadmills today are medical facilities (hospitals, rehabilitation centers, medical and physiotherapy clinics, institutes of higher education), sports clubs, Biomechanics Institute, orthopedic shoe shops, running shops, Olympic training centers, universities, fire-training centers, NASA, test facilities and training rooms of police and army, gyms and even home users.

Treadmill ergometers are now mainly with motor drive. Most treadmills have a running table with sliding plate. Before and after the race table, there are two shafts. Between the shafts and the running deck a running belt is stretched.

Safety standards for treadmills are the IEC EN 957-1 and IEC EN 957-6.

For medical treadmills applicable norms, standards and guidelines are the Medical Device Directive (MDD), European Guideline 93/42 EEC, European Guideline 2007/47 EEC, IEC EN 60601-1, EN 62304, EN 14971 and the machinery directive 2006/42/EC.

Medical treadmills are class IIb active therapeutic devices and also active devices for diagnosis. With their very powerful (e.g. 3.3 kW = 4.5 HP) electric motor powered drive system treadmills deliver mechanical energy to the human body through the moving running belt of the treadmill. The subject is not changing his horizontal position and is passively moved and forced to catch up with the running belt underneath his feet. The subject can also be fixed in safety harnesses, unweighting systems, various supports or even fixed in and moved with a robotic orthotic system utilizing the treadmill.

Medical treadmills are also active measuring devices. They measure the heart rate of the subject. When connected through interface with ECG or ergospirometry or blood pressure monitor (BPM) or EMG they become a new medical system (e.g. stress test system or cardiopulmonary rehab system) and measure also the ECG, VO2max, breath volumes, blood pressure, muscle activity and various other vital functions.

Most treadmills have a “cardio mode”, where a target heart rate is defined and the speed and elevation (load) is controlled automatically until the subject is in “heart rate steady state”. So the treadmill is delivering mechanical energy to the human body based on the vital function (heart rate) of the subject.

A medical treadmill which is also used for ergometry and cardiopulmonary stress test as well as performance diagnostics is always a class IIb medical device either when used as stand alone device in a medical environment or when used in connection with an ECG, EMG, Ergospirometry or blood pressure monitoring device.

On the running deck the subject is moving, who adapts to the adjustable speed of the belt. The running deck is usually mounted on damping elements, so the running deck has shock absorbing characteristics. By a lifting element, the entire frame including treadmill running deck will be raised and thus simulates a pitch angle for uphill running. Some treadmills also have the reversing of a running belt for the purpose of downhill loads. Most treadmills for professionals in the fitness area, run for table sizes of about 150 cm long and 50 cm width, a speed range of about 0 ... 20 km/h and slope angle of 0 ... 20%.

For athletes, larger and more stable treadmills are necessary. Sprinters reach with some weight relief temporarily speeds of up to 45 km/h must therefore run on a large deck of up to 300 cm in length and have up to 100 cm width. At high physical exertion and increased risk of falling a fall stop unit is required to prevent a fall of the subjects or patients. This fall stop device is usually implemented by a safety arch on which a rope is attached to an electrical switch. A harness bears the subject preventing from falling and shuts down the running belt.

In treatment centers treadmills are used with built-in seats left and right for therapists, for example, so the therapists then can move the legs of a stroke patient in order to simulate walking movements and learn to walk again. This is called manual locomotion therapy.

Oversized treadmills are also used for cycling at speeds up to 80 km/h, for wheelchair users and in special applications with thick running belt for cross-country skiing and biathlon, where athletes perform training and testing exercise with roller ski on a running deck of up to sizes of 450 x 300 cm.

Disadvantages

As a cardiovascular exercise:

• Running on treadmills is easier than running on an equivalently flat distance outdoors because the ground is smooth and there is no wind resistance. A common misunderstanding is that it is easier because the ground is pulled beneath you. But the movement is relative and it would be the same as running on the deck of a ship which moves relative the terrain. Studies measuring the difference find that an average person running between 5 miles per hour (8.0 km/h) and 9 miles per hour (14 km/h) will expend between 0 and 5 percent more energy running outdoors. A person running outdoors faster than 10 miles per hour (16 km/h) (6 minute mile pace) will expend up to 10% more energy than an indoor runner. Treadmills can approximate the additional effort of running outdoors by setting the incline to 1%.
• Some treadmill runners develop bad running habits that become apparent when they return to outdoor running. In particular a short, upright, bouncy gait may result from having no wind resistance and trying to avoid kicking the motor covering with the front of the foot.
• Imposes a strict pace on runners, giving an unnatural feel to running which can cause a runner to lose balance.

As an indoor activity:

• Many users find treadmills monotonous and lose interest after a period.
• Treadmills do not offer the psychological satisfaction some runners get from running in new locations away from the distractions of home.

As a machine:

• Treadmill calorie counters overestimate the number of calories burned by up to 15–20%, according to some reports.
• May cause personal injury if not used properly. Of particular concern are children who reach into the treadmill belt while it is running and suffer severe friction burns that may require multiple skin grafts and result in lasting disability.
• Costs of purchase, electrical costs, and possible repair are significantly greater than those of running outside.
• Takes up space in homes.

Other uses

Steers on a treadmill

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. Treadmills can also be used to exercise dogs that are accustomed to running on a conveyor; however tying the leash to the treadmill should be avoided as it can cause serious injury.

Donkey powered well hoist

Omnidirectional treadmill

Main article: Omnidirectional treadmill

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, such as large size, noise and vibration. There are parallel developments being conducted by researchers working on projects sponsored by the Department of Veterans Affairs to create virtual reality environments for a wheelchair trainer in order to promote therapeutic exercise.

See also

• Naturmobil
• Hamster wheel
• Combined Operational Load Bearing External Resistance Treadmill (COLBERT)