Non-contact body scanning and high-precision bicycle measurement using laser technology

Bicycling – A Healthy Activity
The positive effects of bike riding are well known. It promotes the concentration and perceptibility of children and teens, and it is movement that is gentle on the joints and increases endurance, performance, and general well-being. Thus, it helps prevent diseases and increases the metabolism [1]. As a popular sport, bike riding ideally helps maintain health. Of course, it is also a high-performance sport. In both cases, it is important to have “healthy” posture on your bike, even though the reasons for this vary. We are introducing excerpts from established measurement methods that serve this purpose.

Cycling – A Competitive Sport
Not only in Formula 1 racing are the driver performance and material optimized and coordinated to achieve maximum performance, but in cycling as well: whether on a mountain bike, a racing bike, or in a time machine: an optimal sitting position guarantees maximum racing success.
The bike is at the top of the list of things to be optimized. Manufacturers have their own R&D departments to construct bike frames that are as rigid as possible and to improve the aerodynamics in their own wind canals. Of course, professional athletes have their own training schedules. When athletes sit on their bikes, they train with pulse and power meters; the best performance can be achieved with watt-controlled training sessions. The best material and fitness are, however, not enough to win medals. An optimized sitting position is a deciding factor because an ergonomic sitting position guarantees optimal power transmission.

Fritz Buchstaller – Pioneer of Bike-Fitting in Germany
The pioneer of bike-fitting in Germany is located in the triathlon region of Roth. Fritz Buchstaller has been adjusting the sitting position of athletes for many years and is well aware of its importance in improving performance. The professional athletes, primarily triathletes, come from all over the world to profit from his know-how and to have their bicycles adjusted. Athletes should be able pedal in a manner that is as energy saving and stress free as possible. The optimal sitting position is often more effective than the increase in strength that can be achieved by a year’s worth of training. The talk among athletes is of figures of up to 30 watts. By comparison: a hobby athlete can pedal between 200 and 300 watts. Thus, an optimized sitting position could increase performance by more than 10%!

Line Lasers for Initial Adjustment
Fritz Buchstaller is one of just a few authorities in this area; he observes man and machine and uses his vast know-how to adjust the optimal position for each athlete. However, he also uses optical measurement technology to carry out adjustments. For initial bike adjustments, he uses a line laser to help analyze the leg axis during pedaling: the knee must operate upright to prevent long-term damage. A quick calculation: “Think about it: you cycle at 90 rpm, and your knee axis deviates 5 mm from the line. After just one minute, that deviation is equal to 45 cm. You can make your own projection as to how long you sit on your bike, and what effect that deviation has on your physique.” Often, it is enough to make an adjustment in your shoe to correct the axis. Further adjustments are made to your bike until an optimum is achieved two hours later.

smartfit – A System Not Only for Top Athletes
Many athletes are aware of the importance of correct bicycle alignment; however, only a few have been able to properly adjust bicycles. Not only in high-performance sports does the position of the saddle, handle bars, etc. play a major role, but in the popular sport of biking as well. Incorrect positioning even at the hobby level can lead to knee or back problems and ultimately to a loss in interest in this sporting activity. That would be a shame because bike riding is one of the healthiest endurance sporting activities out there because the bicycle carries the body weight.

Laser-supported Measurement of Athletes and Material
Dr. Björn Stapelfeldt, who received his doctorate in sports science, developed the smartfit system with his bicycle laboratory team. With this system, it is possible to undergo a professional ergonometric consultation and receive an analysis of the sitting position, without being a biomechanics expert. This system is based on the laser-supported measurement of body and bicycle, which is carried out in a matter of minutes. A red cross-hair laser module is measured that is integrated in a calibrated rack system. At the push of a button, the individual measurement points are transmitted to the software.

The database-based software is the heart of the measurement system and is where the actual expertise lies. It calculates the deviation from the actual position to the ideal position – depending on the desired wheel adjustment: from hobby cyclist to professional athlete.

Depending on the scope of measurement, the height of the saddle and handlebars, the width of the handlebars, and the length of the handlebar stem and crank handle are determined. Dr. Björn Stapelfeldt’s team carried out over 10,000 measurements prior to marketing the smartfit system: the recommended settings, which are exact to within a millimeter, are based on this test phase. For everyday biking, these settings are often sufficient.

After the static measurements are completed, ambitious athletes are equipped with a camera that is mounted to the side of their own bicycle to record their movement pattern. The recordings are used to determine the joint angle in order to adjust the final sitting position based on this angle – step by step.

Specialized shops profit from this body scanning system, which steers the seller to a range of appropriate bicycles from over 30 manufacturers. If a bicycle has already been sold, a number of different service agents can carry out a bikefitting, which results in an optimal sitting position.

In the U.S.A., the adjustment is practically standard; in Germany, it is slowly becoming more widely accepted, according to Stapelfeldt. In his bicycle laboratory, he advises professional cycling teams; he also has the mountain biker Helen Grobert under his wings.

[1]. Bicycle traffic in Germany: numbers – data – facts. Study of the Federal Ministry of Traffic Control and Digital Infrastructure, 2014.

 

Dr. Björn Stapelfeldt
The founder and general manager of Radlabor GmbH has been professionally analyzing posture in the sport of cycling for 20 years. The smartfit system was designed for specialist stores with the goal of offering a “smart” solution. Complex analyses that require expert knowledge are not suited for the point of sale. Measurements should quickly and easily lead to a bicycle with an optimal fit for each customer.
Radlabor GmbH has its roots in the Olympic training center in Freiburg and the Sport Institute of the University of Freiburg. Intensive collaboration with leading athletes includes the creation of training plans and, of course, the adjustment of bicycles.

Fritz Buchstaller
A (former) professional athlete, Fritz Buchstaller is a legend in the triathlon. In 1987, he participated in the Ironman in Hawaii and witnessed Dave Scott and Scott Dillan increase their performance by approximately 30 watts through the use of aero handlebars. In 1988, he brought this contraption to Germany and mounted it to his racing bike. And that is how his story of the optimal sitting position began: he asked himself how you have to sit on a racing bike to profit the most from these handlebars. Today, he chuckles when he looks back on the accepted thinking at the time: “We initially thought that you have to push the saddle so far forward that you can see the hub on the front wheel. We rotated and shaped saddle supports to make this position possible – with very little success in the beginning.”
The aero handlebars became widespread in Germany in the years to follow; however, the sitting position of athletes was still as dramatic as for Buchstaller in the beginning. He wanted to change this, and so he studied books on biomechanics and opened a bike shop in 1991 – with the goal of helping athletes sit “right” on their bike. (The photograph shows Fritz Buchstaller and Timo Bracht, who placed second at the 2015 Roth Challenge.) Now he adjusts more than 800 bicycles a year; in fact, sometimes you have to wait a very long time for an appointment.

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Laser Modules with a Cross-Hair or Line Profile
Cross-hair and line lasers are primarily used in industry to align and position objects. They are also used to position patients, for example to align them optimally for an MRT.
The measurement of athletes is a rather unusual application. Optimal results can be achieved with inexpensive modules. Classic cross-hair or line lasers are available with red light; however, green light is also available to achieve even better visibility. This is especially the case when measurements are evaluated by the naked eye in daylight.

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Low Cost OEM Modules
FLEXPOINT^® Cross Hair Laser
FLEXPOINT^® Dot and Line Lasers

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Contact Person:	Michael Tuohy
Company:	LASER COMPONENTS USA Inc.
Address:	116 South River Road Building C
ZIP / City:	03110 Bedford, NH
Phone:	+1 603 821 7040
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Email:	optics@laser-components.com