Manpower-driven device with bi-directional input and constant directional rotation output

A manpower driven device having a bi-directional input and a constant rotating direction output, comprising:

• a human foot or hand driven input device (101) for receiving a rotary input in either of two directions or a reciprocating rotary input, including at least one of:
• (a) a pedal, a crank, and a bi-directional transmission wheel train, (b) a handle, a handle shaft, and a bi-directional transmission wheel train, and (c) a manpower-driven bi-directional rotation mechanism device;
• a constant output direction transmission device (102) for receiving a bi-directional or reciprocating input from the input device and producing a constant direction output having only one rotational direction, wherein the constant output direction transmission device includes transmission components constituted by at least one of a gear set, a friction wheel set, a chain and sprocket section, a belt and pulley section, a transmission crank and wheel set, a fluid transmission unit, and an electromagnetic force actuator, wherein a speed ratio between an input end and output end of the constant output direction transmission device is one of a fixed speed ratio, a variable speed ratio, and a speed ratio that differs for different input directions;
• and
• a load (103) connected to receive the output of the constant output direction transmission device, and
• whereby rotation of the input device (101) in different directions exercises a variety of different muscles to reduce injuries and improve muscle strength and density of the different muscles.