Some stationary bike models feature handlebars that are connected to the pedals so that the upper body can be exercised along with the lower body (much like an
elliptical trainer). Most exercise bikes come with mechanisms to apply resistance to the pedals, enhancing the intensity of the exercise. Resistance mechanisms include
magnets,
fans, and
friction mechanisms. Some models allow the user to pedal backwards to exercise
antagonist muscles which are not exercised in forward pedaling. Exercise bicycles are typically manufactured using a crankshaft and
bottom bracket, which turns a
flywheel by means of a belt or chain. The
bearings on these moving parts wear with use and may require replacement. Specialized indoor bicycles manufactured using a weighted flywheel at the front are used in the indoor cycling exercises called
spinning. A variety of indoor
mini-cycles, sometimes referred to as
exercise pedallers, have emerged as portable, low-cost substitutes for traditional stationary bicycles. They are useful when exercisers are unable to access their stationary bicycles from their homes or local gyms when travels or at work. ==Uses==