Dynamic Fitting
The term “Dynamic Fitting” can be used to refer to two distinct types of bike fit: dynamic positional changes, and dynamic motion capture. A dynamic positional fitting is one where settings (like saddle height) are dynamically altered during the course of a fitting session. Parameters like comfort, aerodynamic efficiency, power output, heart rate, and blood oxygen saturation are then assessed using a variety of methods after each “dynamic” change to determine an optimal setting. The FIST protocol developed over the past 20 years by Dan Empfield is an example of a dynamic fitting protocol. “Dynamic” is also sometimes used to refer to the capture of data from a subject while he/she is moving, though this is better viewed as a separate step in the evolution of bike fitting, better referred to as “Motion Capture.”
Motion Capture
Motion capture systems are becoming prevalent at the elite level in all sports. As sport scientists better understand human biomechanics and the ranges of motion that the human body operates within, it makes sense to use the technology available to follow and track the human body so that it can be quantified, analyzed, and optimized. This technology is similar to that used to create video games and CGI movies, and is often expensive. Kinovea and Dartfish are two video-camera-based motion capture systems that are used in cycling. Retul is an example of a camera/LED-based motion capture system that is cycling-specific. It can be used to provide real-time data display and tracks human motion in 3 dimensions, whereas video-based systems are two dimensional.
It should be noted that Motion capture systems are really “just” a tool for the bike fitter. However, Retul technology was developed by experts in cycling-specific human physiology and they have developed a compressive fitting protocol that is tailored to the advantages it provides.
