If we take a look at the entire leg, from the top to the bottom we can see how complicated the motions can be. In his book Science of Cycling, Ed Burke has a nice diagram showing all the various segments of the leg and their directions of rotation. Because these segments are capable of moving in a variety of directions at the same time, it is important to keep them aligned properly in order to apply force to the pedals without their changing detrimentally.

Unlike the parts of an engine or other mass produced machine, human bones are never created exactly the same. The basic design of each joint is uniform, but the actual joint is different in every person. The length, density, diameter and strength of each bone is different with each person. The range of motion and strength of the connective tissues varies dramatically. That means that despite how well things are expected to work as a unit, they don't always meet those expectations. This is why steps must be taken to keep a person's leg moving in a way that provides both efficiency and stability.

The most important connection is the one between the feet and the pedals. There have been a whole host of connection methods developed over the years. The most basic was the cages and straps on pedals that held the cyclists shoes in place. There was a slotted cleat mounted on the shoe to keep the foot aligned properly. The drawbacks to this system were many including no lateral movement and not being able to get your feet out quickly. As pedal development progressed, lots of methods were invented to provide the cyclist with a solid attachment and a controllable range of motion. The other area that also improved was the design of the shoe's ability to hold the cyclist's foot in place in relation to the pedal axle.

When pedaling a bike, the leg's reach dimensions remain somewhat constant except within the shoe itself. If the heel of foot does not remain firmly placed at the back of the shoe, the dimension between the ankle bone and pedal axle is constantly changing. If this dimension is constantly changing, then the cyclist's bike fit is constantly changing with each pedal stroke. When the alignment of the cleats is also incorrect, this compounds misalignment throughout the entire leg. Sometime this results in nothing more than inefficient pedaling. Sometimes it results in injury. Unlike an uncomfortable pair of shorts or itchy jersey, no amount of fidgeting around can resolve bad shoe setup.

Going back to Spike Lee's question "Is it the shoes?", every cyclist should begin with this question when they are setting up their bicycle. The quality of a pair of shoes and their potential benefit should be as important as the brand and model of bicycle purchased. There are some very good bicycles that have geometry which simply will not fit every cyclist. There are also many brands of very good shoes that will never fit every cyclist. The challenge is to match the correct equipment with the cyclist and their needs. The shape of the shoes must match the shape of the cyclist's foot as closely as possible. There will always be small differences that can be rectified with things like insoles or shims, but these are minor problems. No amount a foam padding or variation in socks can compensate for a shoe that is too wide, too narrow, too short or too long.

Once the right shoe is found, the challenge is to have it properly adjusted and aligned to the pedals. This is the only real contact point with the bike. The pelvis rests on the saddle and the hands upon the handlebars, but these are not permanent positions like the shoe/pedal position. It is during this process that the real limitations of certain shoes or pedal systems become obvious. The need for a properly setup shoe/cleat system far outweighs the lightness, aerodynamics or popularity of any pedal design. If an athlete needs to be in a range of four and one half degrees of floatation to insure their knees move properly, then pedals with a range above or below that won't do the job. An athlete should not compromise on biomechanical efficiency. A good pedal design will allow the foot to be adjusted and stabilized on the X, Y and Z axis. This flexibility of adjustment is essential because the athlete's foot moves in these three planes.

Getting the right shoes, getting the right pedal system and getting these parts properly setup is the most important step in the process. There is a follow up process as well. Cleats wear out, shoes wear out, pedals wear out and a record needs to be kept in order to retain the same shoe fit positioning. Manufacturers often change designs from year to year and even a seemingly minute change in sole design can drastically alter how a shoe fits. Having a written record will help guarantee that any changes or replacements don't change setup.