It's important to have a properly fit bike because bicycling is a repetitive sport. When you're riding, your legs are going through a repetitive repetition and if you're not properly fit, that's going to start causing injuries and aches and pains.
When I perform a bicycle fitting, I look at the different angles and landmarks on the people to find that optimal position. There's optimal angles to be on a bike that gives the best performance and also the most comfort. I will start looking at the feet, work up to the knees, then work up to the back, shoulders, and then to the hands.
Looking at the proper angle might be, "How does the foot sit on the pedal?" Looking at the knee would be, "What's the angle of the knee in relation to the hip?" Then we look at the trunk angle in terms of how the person's sitting and what's the position of the trunk.
If the angles aren't correct, the body isn't in an optimal performance position and then you start developing overuse injuries. Some examples of overuse injuries might be patella femoral pain, knee cap pain, might be low back pain. It might also be numbness in your hands. It might even be some numbness in the pelvis.
