using both legs together

No..

Walking running and biking do use both legs...any use of a leg for a 'power stroke'requires that it returns to it's 'pre power stroke position' It doesn't matter if this is done both legs together or one at a time.

Frogs do it both legs together, but you get a pause between each hop, ... But in basic terms the averaged power output over time is going to be the same.

Del

I want a tricycle. Seriously ! I've seen ones where the rider is almost lying down, which seem to work OK. The thing is, they all use conventional peddles. What if the peddles were arranged on some sort of ratchet bar, so your feet could push back and forth horizontally ? You could get much more 'oomph' for starting, and if they were independent you could use a double push stroke for extra power. It's got to be more efficient than moving the feet in circles. My OTT version would also have a massive flywheel for building up to 'turbo-start' mode, but I haven't figure out the cornering problems yet.

Experiment! Experienced cyclists use special shoes that clamp onto the pedals! This is so they can also pull the pedal back up when they need to get a boost in power! This is only done in short bursts due to the fact you are putting more energy into the pedals and the quicker you tire! As for walking or running??? Try running to the shop then on the following day try jumping to the shop! Jumping is a burst of energy in the direction desired. After a few bursts of raw power, you are tired. (well I would be!) Running uses the momentum gained by small inputs of forward motion imparted by the legs. Again, it uses energy, but at a more controlled rate. If we sprint, we try to push as hard as we can, so we use bursts of energy so we tire quickly!

Anyway, after reading your question again, I think I got side tracked a bit! Never mind, I was pleasant talking to you!

Try this one for size! Jumping is like driving in first all the way to the shop! Much easier to change into 2nd, 3rd.... uses less gas but the first corner came up quick!

No, forget it! I've lost my way

Rowing a tricycle

One possible advantage of using both legs at once is that one can more easily combined it with arm and back muscles that is, a rowing motion. A problem of course, is steering. However, it should be noted, that paraplegics who ride bicycles and tricycles using arm power only are able to steer with their arms even though their arms are the power source.

Humbaba