Originally posted by: NeoPTLD
Is there anything that can utilize our strong muscles better than a bicycle and is more effective as a transportation tool?
Your question actually has less to do with which type of vehicle is more efficient, and more to do with where you plan on going. The most efficient way to travel on smooth roads without aerodynamic help is an upright road bike. The most effective way to travel off-road will be a mountain bike. If you limit your path to relatively level roads and you use some sort of fairing, then a recumbent is probably a better choice. If you plan on carrying cargo, you will likely need a custom bike frame with storage built in - regardless of whether it is recumbent, road, or a mountain bike.
There seems to be some confusion about recumbent bikes and what they are good for. For starters, there is an incredibly large variety of recumbent and semi-recumbent body styles, and they are not all created equal. Making blanket statements about recumbents just doesn't work. Some misconceptions include:
Recumbent bicycles are more aerodynamic. This is both true and false. It is true that most semi-recumbent seating positions offer a smaller frontal area than an upright, but the shape of an upright rider in a tucked position has been found to have less drag force than the 'bent rider. If any of you know anything about aerodynamics, you know that two of the components of the drag force equation are the "cross-sectional area" (L^2), and the "drag coefficient" (the "CD" that is often quoted) among others. Bents will typically have a smaller area, but a larger CD than an upright. To fix this, bents will often use some sort of fairing to help improve their CD. Fairings are (usually) easier to attach to bents than uprights, and if attached to both types will result in nearly identical CDs for both. At this point, the bent with its smaller area will have the aerodynamic advantage. Comparing a faired bent to an unfaired upright shouldn't even be close. Of course, I have seen some really bad implementations of fairings on bents that actually made things worse.
The recumbent pedaling motion is more/less efficient than in an upright. Neither. The pedaling motion of a bent is the same as an upright, or at least it should be if designed properly. Dr. Danny Too conducted several experiments on the effects of rider positioning on power output and found that the optimal seating angle for a recumbent was as if you rotated an upright rider in a tucked position. Many bents either have too little or too much lean in their seat. Leaning your seat way back will usually increase your aerodynamic efficiency at the cost of power output, which is why many racing bents are like this. Most bents are still hand made by enthusiasts, so much of this research isn't actually utilized by people with extensive scientific or engineering training. The "pulling up" on the pedals mentioned by Peter is actually a function of the pedal/shoe interface. Almost all bicycle racers, upright or bent, use some means of snapping their shoes into special pedals to increase their pedaling efficiency. You don't pull up against your seat though. At the same time you are pulling up on the one pedal, you are pushing down on the other. Since your quads are so much stronger than your hamstrings, you can actually pull up while in the standing position. The biggest advantage of these pedals isn't just being able to pull up, it is the ability to pull/push forward and backward instead of just up and down. The circular motion allows for a more constant flow of power to the rear wheel and allows for higher pedaling rates. Standing up is still an advantage for going up long hills, but it can be designed around. The standing up motion allows you to lock your knee joint temporarily and allow all of your muscles to rest for split second. However, you still have to flex your other leg to get it into the standing position so you can shift your weight. Of course doing this means you cannot use the circular motion described earlier. Bent riders can never do this, so they have to use the circular motion at all times. The problem with most bents is that they are usually geared to high. Because they can push so hard against their seat back (and because they get moving really fast down hills) , they feel more comfortable with a gear range much higher than on a regular upright. When you combine this with the poor design and standard pedals, then going uphill becomes next to impossible.
There are some things worth considering though. For the standard circular pedaling motion, the human body is better at generating torque at lower rpms, but better at generating power at higher rpms. Because professional cyclists are usually concerned with maintaining high speeds, high power, and therefore high rpms, are what they use the most. When climbing hills, however, much of your momentum is lost in between each stroke, and you must therefore accelerate a small amount each time in order to maintain a relatively constant speed. Acceleration is a function of torque, so you will see cyclists much more likely to "stand" in a higher gear than "spin" in a lower gear while climbing hills. This is why standing on uprights is still an advantage for going up hills. Also worth considering is the effect of blood flow. If a bent is designed with the crank center above the seating position, then the blood flow to the legs will decrease, and muscle efficiency will suffer. I have personally felt the tingling in my feet on one particular bike I rode. When going uphill with your legs in front of you, this effect can become much worse.
As someone who has many years of experience with Human Powered Vehicles (HPVs), I have seen some really unique (and downright wackey) attempts at improving human powered propulsion. I can say without a doubt that the number one parameter in making a vehicle fast is the rider. Lance Armstrong on a 1970's Schwinn would smoke the vast majority of HPVs with Joe Blow in the seat. The next most important factor is mechanical efficiency (including seating position). You really shouldn't worry about aerodynamics unless you can go faster than 30 mph unfaired, or unless you plan on going a long way in between stops. If you've got your ducks in a row, then maybe you can travel further than 50 miles in one hour like the record holder at IHPVA.org. Mind you, that isn't a peak speed of 50 mph, that's an average speed of 50 mph -
for an entire hour!
Of course if there were only one answer to the "more effective transportation tool" question, then why do we have so many types of cars, trucks, and trains? Each vehicle is designed to perform in a certain way, and this makes some vehicles more effective at some tasks than others. If you don't have a place to park your bike, then your razor scooter may be the better choice. Bents have some drawbacks and advantages that make them more suitable for some tasks than others. Some people just prefer the seating position while others can't stand it. Bents have very poor visibility in automobile traffic and would do poorly as bike messengers in New York City. Because I race HPVs on racetracks, I have a narrow set of parameters to work with, and recumbent style bikes are better suited for my purpose. They are not the best choice for all.