This isn’t true. A search on “pros and cons of recumbents” reveals that a lack of power is one of the disadvantages. Yes you can bench press your body weight with your leg/s but you can only do it for a short amount of time. A cyclist on a diamond frame gets helped by gravity and doesn’t have to use only their muscles.
Condensing a few of the above points. The OP asks about efficiency. The question about recumbant versus conventional bicycle, and indeed versus walking will come down to the same thing. A bicycle provides a mechanical impedance transformer. It doesn’t matter what the peak power output of the human frame is, sure you can lift vastly more than your own weight, but this has nothing to do with efficiency. What a bike does is allow your body to run at its most efficient power output rate, and then transforms that power to motion. So your body ticks over at its sweet spot in a manner that is independent of the actual speed of motion of the bicycle. You can’t do this walking as the speed of travel is tied directly to the physical motion of your limbs, and a recumbent may or may not allow the body to find as good a sweet spot as a conventional bicycle, although it may provide better aerodynamics.
I asked the same question several years ago, here’sthe thread.
What do you think they are using? Magic? They may be able to use a greater variety of muscles, but gravity only helps you push the pedals down after it has hindered you in lifting yourself up.
Whereas on a recumbent, gravity doesn’t help you at all, so you’re using “only your muscles”.
Sorry, you ain’t gettin’ it. Gravity does not help you at all. All it does is give you back what you just put in.
It changes the ways you have of putting things in. On a recumbent you can only extend your legs as fast as you’re capable of turning the pedals, and imparting energy to the bike can only happen by moving your legs. On a regular bike you can raise your body and then rest and let gravity repay its debt. Of course, you already know this, but disagree with the semantic content of “using only ones muscles”, so we’re not actually getting anywhere.
Yeah you are right, that occurred to me after I posted. You don’t get a free ride on a diamond frame, but you get a variety of positions that allows you to change the muscle groups used. The fact is, regardless of why, you can’t actually get as much continuous power output on a recumbent.
This is the reason why the rickshaw drivers in Calcutta still run and pull their rickshaws. In most of the other cities in India, bicycle rickshaws have replaced the original design, but in Calcutta, the monsoon rains create sometimes 3 or 4 feet of rain in the streets and bicycle rickshaws become worthless.
Bicycles don’t magically appear.
No one has mentioned the “energy” it takes to manufacture a bicycle, so that one can use its efficiency to get around.
Very few people are going to make their own bicycle so people are going to have to work and earn money to buy one.
Figure on having to earn $400. to buy a $200 bicycle (after paying various federal, state and local taxes). How much energy do you have to put out to earn $400.? How long does it take to break even on the amount of energy you put out to earn the money to buy the bicycle and the amount of energy the bicycle saves you as you use it?
Turns out my e-mail service doesn’t like big attachments, so I uploaded the article I mentioned previously. It’s a 6 MB pdf file.
Here is the link:
That depends. If you use the bike in a messenger service, you get to deliver more messages than you would walking so you get more $$ back than you paid (and you get a tax deduction offsetting part of the taxes you paid, so you might even come out more efficiently by your standard. Even if you don’t use your bike commercially, if you ride to work you save time over walking, and $$ over gasoline, etc. So if you’re gong to start throwing costs into it, the calculation is going to be very complex.
As an interesting side note, if the cross section of your terrain is a catenated curve you can ride a bicycle with square wheels on it.
Not unless the length of the curve segments matches the length of the sides of the square wheels.
Obviously it depends on numerous factors including your rate of earning and how much you use the bike.
It takes me about half an hour to walk to work and about ten minutes to ride. So that’s a 40 minute saving per day or a 200 minute saving per week. Call it three hours a week saved. How much that time is worth is not capable of objective calculation, but I think for most people the answer would be such that you would pay off the cost of the bike very quickly indeed. Not everyone has my commute of course. Most would be longer.
Of course whilst time is money, time is not energy. Indeed energy is that which is conserved over time. We just move it about. Moving energy about over time is power. Now money is power, but for different reasons. 
Is that relevant though?
I spent a touch over $3000 on my bike which would cost me about 30 hours of actual work (I do a lot of reserve time which, when you break earnings down to a per hour basis of actual work done, skews the data a fair bit.) But the thing is that I would have worked those hours anyway, and it wasn’t a choice between the bike or walking shoes. If I didn’t get the bike I probably would have got a nice stereo, or a guitar. Basically it is a luxury item for most people. If they really do get a bike purely for transport then a few hundred dollars would be close to the mark, and that compares favourably to a couple of pairs of good walking shoes. Take into account fuel not used and car maintenance not done and you’d break even very quickly I’d think.
Well of course. Who would try to use a square wheeled bicycle without checking that first?
Using my bike to ride to the station for work saves me, each day:
£7.50 car parking
£4.00 Tube fare
£2.20 petrol (11 miles @ 20p a mile)
That’s £13.70, or almost £55 a week based on my four-day working week. £2,850 a year. The bike cost £1,000 – not a cheap bike – and even then it had paid for itself in a little over four months.