My hand & foot recumbent trike.

[Jin-Man Choi]

When I first collected the data to create my own hand and foot powered bicycle, I realized the followings:
As we can notice that human beings who walk erect are slower in walking than animals which walk with four legs, I found that a bicycle which is powered by hands and feet is much faster than a bicycle which is powered by only feet. So, I noticed that I need to create a bicycle which people can exercise their whole bodies with.

http://blog.naver.com/cjm6394/70029571364

[BlazingPedals]

While you're right about humans not being the fastest animals on the planet, adding power from the upper body does not increase the power available. The muscles in the legs and glutes are our largest, strongest muscles. An athlete can max out his aerobic capacity using only his legs; so using additional muscle groups to generate power will decrease the wattage available to the legs by an equal amount.

Interestingly, a trained human runner can run a horse to death. The horse is faster, but must rest between sprints while the human draws closer and closer. The race doesn't always go to the swift.

[gcottay]

You have an inventive machine. I think you are on the right track in suggesting it for exercise rather than transportation. It might, though, be useful to a person with limited leg strength who still wants to get around under his/her own power.