Nowadays astronaut's health in space depends on many factors. Two of them physical activity and gravitational force. My idea to use simple training tool (picture 1).

Tool consists of three main parts:
1) one (or two) wheel bicycle.
2) frame
3) shaft.

Bicycle connected to frame which is connected to shaft (picture 2).

Such a tool is useful to increase physical activity of astronauts on space station.

Centrifugal force creates additional load on the body (picture 3 A,B,C).