What is Retul?

Retul is the most advanced bicycle fitting system available today. The system incorporates an amazingly precise three-dimensional motion capture technology, immediate report capability, and millimetre-specific digitizing tool to provide the most accurate dynamic fitting solution in the industry.

Bicycle fitting is best measured during dynamic pedalling action. Static measurements tell the fitter very little about how the rider's body reacts and interacts in biomechanical motion. The Retul system reads the body in motion, in three dimensions. An observer watching a cyclist while pedalling cannot measure lateral, vertical and horizontal movement. The Retul system eliminates the guesswork and assumptive nature of fitting, providing the fitter with the most accurate data set available in bike fitting. The result is that the rider will have a true fit to his or her bike, maximizing efficiency and performance while avoiding discomfort or injury.

Retul bike fit technology incorporates three main data points in fit theory:

Bike Fits Must be Dynamic

Most bike fitting specialists fit riders in a static position. This is because the traditional tools of the trade - tape measures and plumb bobs - do not allow accurate measurements while the rider is pedaling. Using motion capture technology, Retul records the rider's positions in motion, therefore creating the most realistic picture of the rider's actual pedal strokes and body positions when out on the road and trails.

Measurements Must be Accurate

Measurements made by traditional tools have one thing in common. They are subject to human error and therefore can be devastatingly inaccurate. Even slight inaccuracies can drastically change the rider's feel after a ride. The Retul system is accurate to within less than a millimeter, creating true objective data which can be utilized by the fitter for the perfect biomechanical fit.

Biomechanics are Best Assessed in Three-Dimensional Space

Fit data collected in a traditional two-dimensional plane (i.e. video-based systems) is fairly limited because the fitter can only look at one view at a time, and those views stand as independent reference points. In order to make the best fit recommendations, the fitter must realize that the front and side views are actually interdependent reference points. In other words, the front and side views must be viewed simultaneously in three dimensions in order to see how all the applicable movements of the body are working together. Retul uses a 3D motion sensor to simultaneously gather data on multiple angles of the rider.

Our software is designed specifically for bike fitting. All data collected in the pre-fit interview is input into specific fields. All rider interview and fit data is stored in individual client files, which can be accessed at any time to compare previous fittings with new data. Readings taken throughout the Dynamic 3D motion capture process are immediately processed and a report is generated. The fitter then analyzes the data from this sample and evaluates the need for changes in the rider's position. Once changes are made, the process is repeated to verify effectiveness. This new data then becomes part of the final report, in addition to post-fit bike and equipment measurements. The software can track information for multiple bikes for each client so that fits across categories (road, mountain, cross, etc.) are distinct. A historical position Report can be generated at the push of a button from any of these files for quick comparison or reference. Our goal was to create useful software that collates and keeps information organized for maintaining client history and easy accessibility. Retul software is user friendly and will enhance the fitter's interactions with his or her clients.

Retul is Active

The system uses infra-red LEDs (light emitting diodes) that get placed on the body in specific skeletal locations. Active systems differ from passive systems in that the tripod mounted LED sensor is tracking the light directly from the source (the LED diodes). Passive systems use reflection (light returned to its source via a material that repels the light source) to track markers. The problem with reflection is that many shoes, clothes, bikes, and other objects have a lot of reflective points on them, so false images known as artefacts get picked up by the system. In most cases, the user has to go into software, distinguish between the desired markers and manually delete these artefacts. In a shop with windows and shiny bike parts everywhere, this can be highly problematic, as covering all of those sources is a near impossibility, requiring the time consuming removal of artefacts before data collation can begin. Retul's active system does not suffer from this problem. The active system flashes each LED discreetly as the infrared light travels from the LEDs on the body points to the sensor on the tripod. The sensor then triangulates the position of the LED in true 3D space. Our system can track these points to within a millimetre of true position. Data collation is immediate and fast.

Retul is Fast

The system flashes an LED every 2.1 milliseconds - that is 476 times per second or Hertz. The system takes a full set of body measurements every 34 milliseconds, or 29 full sets of body data per second. Our sample sizes, taken dynamically, last anywhere from five seconds to five minutes - whatever the fitter desires. The software processes all of that data in seconds, synchronizing the eight data points tracking them across longitudinal, vertical and horizontal planes.

Retul is Synchronized

Synchronization yields body location intelligence. The receiver knows what LED is flashing and where it is on the body. The software automatically, by skeletal position, identifies the proper LEDs for the measurements of each marker's position. This is virtually automatic, unlike in passive systems, in which the user must tell the system what reflection images are related to what marking point. There is no post-processing needed with Retul's software, so reports are accurate, 3D reports are generated immediately for viewing.