Rowing bike

Sculltrek

youtube movie of the sculltrek.
The scultrek website.

There are lots of rowing bikes of which I will write later.

This one is new to me and I wonder why the inventor chose this specific motion, which seems strange to me as both feet and body move forward during the stroke. This moving around of mass is inherently inefficient, this is where Derk Thijs has a better motion-force system.

Interesting mechanic and the flow of the motion looks interesting also.