FAQ's PAGE TWO
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In the testing there may be faulty data or mistakes in machine operation by the person performing the test. How is this faulty data discovered? In watching a rider on a bike placed on a trainer, how can you measure and quantify the improvement of the energy cost? Is it just a question of looking “right” on the bike, for that one or two hours, based on that fit person’s experience?
For starters, the determination of the optimal energetic position cannot be given during a single analysis (one fit session) anyway.
The determination of the optimal energetic position requires nearly 8 tests over a 3-month period in order to test the cyclist in a situation of locomotor pattern stability (the new/altered position must have the requisite adaptation time – 600 km’s across all levels; certainly someone who rides more will reach the 600km mark quicker).  If not done this way, the variations which you observe will not be directly dependent on the positioning of the cyclist but simply on a modification of the locomotor pattern (position) which deteriorates muscular coordination. Position changes require adaptation time before a determinant on efficacy can be made.
Comfort:  How do you measure comfort in an objective way?  What are the parameters which you measure scientifically and what allows for affirmation that the cyclist is in an optimal position for comfort?  Certainly looking at the rider on a home trainer during one session of analysis cannot determine if the cyclist is in a situation of comfort.  Comfort is directly related to concepts of biomechanics and muscular tension.  However, the medical data clearly indicate the respected angles of articular and muscular request in order to avoid all hyper postural requests that would generate arthralgias.  In short, the medical community has researched the ranges to which muscles and joints should be subject before negative consequences are engendered. The CPS draws on this.
Power:  What is the good position in terms of power?  Is it the one that makes it possible for the cyclist to develop the greatest power?  Perhaps, but which power are we talking about?  Is it referring to the PMA, anaerobic Pmax, Ppic...?  In fact, the “right” type of optimized power depends on the cycling discipline (road, track, tri, etc.). Let us take the case of Laurent Gané, multi-time world champion track cyclist. He was positioned by the CPS in order to develop the largest anaerobic Pmax because he does the sprint and keirin on the track.  As a world class athlete Laurent Gané developed Pmax of more than 2600 Watts (during Wingate test) at his best. On the other hand, if you position a Tour cyclist you must seek a position which optimizes the PMA and especially the level of the anaerobic threshold.  Indeed, with respect to Tour cyclists, they are not always the cyclists who develop largest PMA which are the best. The best are those who have anaerobic thresholds very high and very close to their PMA.

Example: 
Individual 1: 
PMA = 500Watts (individual = 70kg), is 7.1 w/kg
Threshold = 94%PMA = 470Watts
Individual 2: 
PMA = 520Watts (individual = 70kg), is 7.4 w/kg
Threshold = 89%PMA = 463Watts

Attention, even though this is an essential parameter it is not sufficient... Indeed, Individual 1 will not be able to compete with N°2 if his output is not optimal.  Thus it is absolutely necessary to correlate the values of power to the threshold, of PMA, of VO2, VT1 (Ventilatory Threshold), VT2, LT1 (Lactate Threshold), LT2... The whole picture must be considered. The short version is that the criteria of performance of HEALTH and COMFORT cannot be analyzed individually during a specific analysis because the modifications measured are only tied to the fact that you changed the position. There is no way to check if the position is optimal because the proper adaptive time hasn’t been given.  Moreover, during the analysis of one individual, the risk related to the error of measurement (failure of the material, error of calibration, moisture in sample line...) could not be controlled. In short, the differences in actual values are more likely due to skews of measurement than by a real impact from the new position.

2. Does a bike fit change over time as flexibility, strength, body composition, riding style and goals alter? If the CPS is fit to where my optimal position "should be" will that position cause discomfort and at worst, injury? Isn't it better to make small changes incrementally over a period of time, making sure at each stage that I can adapt successfully?
An individual’s increased physical level during the season will enable him to tolerate different and typically more extreme positions.  The tolerance doesn’t mean that the position is correct, though. If that is true from a point of view of comfort (the limit of comfort is extended and the rider can tolerate more during the summer as compared to early spring, let’s say), you must remember that you will generate problems on the physiological level (oxygen transfer, power transfer, muscular operation, amplitudes of optimal work...) without being able to perceive this. Moreover, it is important to understand that a good position does not depend on the point of time in the season... It is not the limit of comfort that determines the proper position; such an approach is incomplete. It is not because the cyclist feels ok that he is well-positioned!

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