A static bicycle is an exercise bicycle on a stand, where the wheels turn but the bicycle stays still.

static bicycle
Exercising one limb on static bicycle.

 

For knee rehabilitation they can be used for gently improving range of motion, or for building up strength and endurance.

Synonyms: 
static bike
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An overview of the issues that need to be taken into consideration when using cycling as a tool in rehabilitation of knee problems.

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