Retul Motion Capture Technology
What is Retül?
The Retül system uses infra-red LEDs (light emitting diodes) placed on the body of the rider in specific skeletal locations. A 3D scanner is then used to measure the location of each LED 29 times per second. This allows rapid collection of real information about a rider's position and movement while riding under load. The Retül analysis software synchronises with our Cycleops Powerbeam Pro trainer recording real time power data at the same time as rider motion. Retul is used by a number of top level pro road and triathlon teams including Team Sky, Lance Armstrong's Team Radio Shack and Team Trek K-Swiss for fitting and bike set up. Multiple Ironman world champion Craig Alexander and Ironman champion Norman Stadler both use Retul to optimise their comfort and power output on the bike.
Why use Retül?
1. Retül is FAST
Using the Retül system allows our fitters to collect and analyse large amounts of rider data and quickly assess results of geometry adjustments
2. Retül works in 3D
3D Motion capture allows our fitters to study rider movements in 3 dimensions. A tracing of knee motion is produced automatically each time a set of measurements is taken allowing the fitter to make informed judgements regarding the adjustments needed. No other measurement system can record movement in both front and side views simultaneously.
3. Retül is dynamic
Most bike fit specialists fit riders in a static position. This is because the traditional tools of the trade, tape measures and plumb bobs don’t allow accurate measurements while the rider is pedaling. Retül captures the rider’s position relative to his pedaling motion, and therefore creates the most realistic replication of the actual pedal stroke and body position when out on the road and trails.
4. Retül uses averages
While we strongly dislike (to put it mildly) fitting philosophies that measure rider body dimensions and then guestimate "optimised" geometry without ever seeing the rider on a bike, Retül uses averages in a powerful way. 29 sets of results are taken from the rider during each second of the measurement period (normally around 15-30 seconds) and then averaged. This gives the Retül system a strong advantage over other motion capture techniques (such as video capture) as no two pedal strokes are the same. Video capture measures angles at a single point during a single pedal stroke. Retül measures angles constantly throughout many pedal strokes.
5. Retül is 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 completely change the rider’s feel after a ride. The general rule is that if you feel pain, something can probably be changed to eliminate that pain. Retül uses motion capture technology accurate to within less than a millimeter, creating true objective data which can be utilized by our fitters for the perfect biomechanical fit.
What Retul Isn't
Retul is a measurement tool designed to provide a skilled bike fitter with highly accurate information with which to base fitting decisions. A key skill of a good bike fitter is observation. Rider bio-mechanics on and off the bike, rider motion and habits while riding, rider experience, fitness and goals all play a large part in the fit process. Retul is not a fitting system and the Retul software will not recommend or calculate bike geometry and set-up changes based on the readings it takes. A "Retul Fit" still depends greatly on the skill and experience of the fitter performing the fit. Bike Science fitters are highly experienced and trained to the highest industry standards which when combined with the advantages of the Retul system make for the very highest standard of fit available.