This subject is related to Cycling cadence. It relates to the benefits of cycling, the benefits of pedalling fast (hence avoiding muscular stress to the knees), but it also relates to an activty that is often practiced in the gym rather than on the open road.
Spinning is an expression that started with cycling ond cyclists. It is the practice of pedalling with a cadence of 80+ turns per minute, preferably 100+ turns per minute, regardless of the terrain - whether you are cycling on a completely flat road or up a steep hill.
One of the key benefits of spinning is that it provides as much exercise for the heart as the legs, and very little shock to the muscular system.
The heart will typically reach 80% of 'maximum heart rate' reasonably easily in spinning, even while your legs are not too exhausted, and is thus a particularly effective form of general exercise.
The term spinning has also now been adopted by cyclists during the winter, when they train at home on indoor bikes, and more recently by gyms and sports centres around the world that offer 'spinning' classes.
These spinning classes will consist of mixed cycling on indoor training bikes, lasting perhaps one hour in total, and including a mix of cycling techniques, from warm-up exercises in a very easy gear, through fast pedalling with relatively slow resistance, to short stretches where the bike is set to high resistance, to emulate hilly terrain.
Whether you are spinning on the open road or as part of a gym training session the goals are the same, and simple - to exercise the heart and lungs, and to a lesser degree the legs, in order to improve overall fitness and health.
The level of exercise will also ensure that a significant amount of energy (calories) are used during the session - cycling sessions will commonly use use 600-1000 calories per hour.
Gym based spinning classes are a popular way for cyclists to retain their form and level of fitness during the months that outdoor cycling is impractical. Used properly they can go beyond that, and actually enhance the cyclists abilities. They also enable the cyclist to stay 'on the bike' for 12 months a year if required.
Note: if you don't like going to the gym and have some money available, there are various training bikes now available that come with videos and DVDs that enable you to cycle the great cycling routes of the world in the comfort of your own home as an interactive experience! And the less wealthy among us will find that our training bikes all come with a variable resistance/effort and work just fun in front of our favourite TV programme!
While spinning and its benefits are most widely touted in the gyms and sports halls of the world, let's not forget - cycling is just as healthy and much more fun when you get out on the open road on a real bike!