Indoor cycling is a form of high-intensity exercise that involves using a stationary exercise bicycle in a classroom setting. The concept was created in the 1980s when Schwinn and ultra-endurance athlete Jonathan Goldberg ("Johnny G.") introduced the Spinning program. Participants set goals based on their heart rate, which can be measured by hand or using a heart rate monitor and rides simulate variations in terrain by altering resistance and cadence. If someone is new to indoor cycling and has not yet purchased a heart rate monitor then they can judge their level of exertion on an RPE (relative perceived exertion) scale. This scale has numbers which range from six (no exertion at all) to 20 (maximum exertion). Instructors will guide classes by mentioning what level of exertion a participant should be at.

The "Spinning" program, which is licensed by Mad Dogg Athletics, is the original indoor cycling program and was taught on Schwinn bikes. Since its launch several competing programs, and bike manufactures, have emerged, including "Studio cycling," operated by Reebok, and "Power pacing," from Keiser. The "Spinning" program is currently partnered with bike manufacture Star Trac, while Schwinn Indoor Cycling is an independent program which can be taught on any brand of bike, although Schwinn Fitness, a division of Nautilus continues to manufacture several indoor cycling bikes. Because "Spinning" is a trademarked name many fitness facilities are getting away from referring to their programs as such, and instead identifing them as Indoor Cycling classes.

A typical class involves a single instructor at the front of the class who leads the participants in a number of different types of cycling. The routines are designed to simulate terrain and situations encountered in actual bicycle rides, including hill climbs, sprints and interval training. Coasting downhill, obviously, is easiest to simulate. The instructor uses music and enthusiastic coaching to motivate the students to work harder. Most instructors will lead what is called an interval ride, this is where students will sprint, run, climb, and jump all in the same ride but there will not be definable pattern to the exercises.

Each person in the class can choose their own goals for the session. Some participants choose to maintain a moderate, aerobic intensity level, while others drive their heart rates higher in intervals of anaerobic activity. Besides being a great form of aerobic activity (burning between 400-600 calories in 40 minutes), spinning is also beneficial in strengthening the muscles of the lower body. It tones the quadriceps and hamstrings, along with working the back and hips. It can be difficult to stay at the moderate level in a class that is geared towards more intensity. If the exercise is not done correctly, injuries can occur; problems with the lower back and knees are most common. To avoid injury it is important to make sure the seat position is right for the participant's height. The seat should be set at a height such that the leg is fully extended with the foot resting on the pedal. Handlebar height can be adjusted for comfort; less experienced rider may want to set them higher to ease lower back discomfort.

Classes generally use specialized stationary bicycles. Features include a mechanical device to modify the difficulty of pedaling, specially-shaped handlebars, and multiple adjustment points to fit the bicycle to a range of riders. Many have a weighted flywheel which simulates the effects of inertia and momentum when riding a real bicycle. The pedals are equipped with toe clips as on sports bicycles to allow one foot to pull up when the other is pushing down. They may alternatively have clipless receptacles for use with cleated cycling shoes. Stationary cycles used in classroom settings often do not have the electronic features found on some models.

The difficulty of the workout is modulated in three ways:

1. By varying the resistance on a flywheel attached to the pedals. The resistance is controlled by a knob, wheel or lever that the rider operates, causing the flywheel brake (a common bicycle brake, a friction wheel, a magnetic eddy-current brake, a viscoelastic fluid brake, or a strap running around the flywheel) to tighten. On most bikes the brake can be adjusted from completely loose, providing no resistance to pedaling beyond the inertia of the flywheel, to so tight that the rider can not move the pedals. Usually riders who can not pedal at the resistance called out by the instructor are encouraged to ride at a level at which they feel comfortable yet challenged.
2. By changing the cadence (the speed at which the pedals turn). Pedaling slower against high resistance expends more energy than pedaling faster against low resistance.
3. By sitting or standing in various positions:
   • Forward, with hands at the front-most part of the handlebars where the handles are parallel to the sides of the rider's body, used only when out of the saddle
   • Middle, with hands on the 12-14" part of the handlebars that crosses the rider's body
   • Rear, with hands at the center part of the handlebars

Each of these positions works the muscles in slightly different ways. Proper form for standing while pedaling requires the body to be more upright and the back of the legs touching or enveloping the point of the saddle, with the center of gravity directly over the crank. The center of gravity or pressure of body weight should never rest on the handlebars.

The three positions used in indoor cycling each work a different part of the body and it depends on the level of exertion whether or not someone changes position or the instructor can tell the class to change. Position one is when the rider in the saddle (seated) and the handles are resting on the center of the handle bars. Position two is when the rider stands up but can still feel the saddle between their legs and their hands are light on the handle bars because they are only there for balance. Position three is used for heavy climbing and the body is extended over the handles. It is important to remember to always be light on the handle bars because they are only there to help one balance and to adjust resistance accordingly when changing positions otherwise one's feet might stick in the pedals.

Most indoor cycling classes are coached with music. Riders may synchronize their pedaling to be in time with the rhythm of the music, thus providing an external stimulus to encourage a certain tempo. Often, the music chosen by the instructor is dance music or rock music set to a dance beat (i.e. 4/4 time), but not necessarily. This tends to help motivate participants to work harder than they might otherwise. The instructor also may choose specific song for sprints, climbs, and jumps. While the music provides a tempo cue, the cadence does not need to be a multiple of the beat in order for the rider to feel in rhythm; the music therefore helps a rider maintain any constant cadence, not just a cadence that matches the beat.

It is recommended when riding in a class to bring plenty of water. Indoor cycling is very energetic and causes a lot of sweating, and a person who is near dehydration can easily be dehydrated by the end of an hour of hard riding. One ounce (30 milliliters) of water consumed for each minute of work is the recommended and safest hydration ratio, but this could be varied depending on your weight.

The flywheel resistance control is also used to brake the flywheel. When changing from fast pedaling to slow, the flywheel brake may be used to slow the flywheel rather than allowing the force of the angular momentum to be applied to ones knees and legs.

Spinning as a bicycling technique

Spinning on a mobile bicycle refers to the technique of using a range of gears to maintain a constant rapid cadence of 60-110 rpm in controlled, even pedal strokes. This technique is recommended to improve bicycle control, aerobic fitness and endurance. Lance Armstrong notably uses this technique even on steep climbs.