
The popularity of stationary bikes as tools for cardiovascular exercise (these bikes are second only to treadmills in common usage) is due to two factors. Stationary bikes offer low-impact exercise with movements that are familiar to most people. Additionally, the low-impact nature makes them great for older people and those who have had joint troubles.
The other factor has to do with convenience. With a stationary bike in the house, you can easily get your workout while watching television or catching up your reading.
There are three main styles of stationary bicycles: upright, semi-recumbent, and recumbent. Upright bikes are most common and are the most similar to your average moving bike. With semi-recumbent bikes, you are seated lower and your legs are more in front of you than beneath. Recumbent bikes are similar, but the seat is even lower and your legs higher, at chest level.
The following articles are a great place to start your stationary bicycle research.
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