Then vs Now – What has changed in bike fitting within my lifetime
I have been playing with the principals of bike fit for nearly 10 years, and riding bikes just short of 20, so it would be completely fair to say I am not new to bikes. I started young and had enough talent as a junior to be afforded some advice from the best within our community at the time. What I realise in retrospect, is that the general principals of bike fit have not changed, but the accuracy has improved as have the definitions.
The Basics circa 2000 vs The Basics 2017
Legs not too straight at the bottom of the pedal stroke, limited hip rock.
Leg extension between 180-35deg and 180-40deg where the dorsiflexion of the heel is between 65 and 75 degrees (heel drop).
Knee should be over the ball of your foot at 3 o’clock with your foot parallel to the ground.
Head of the fibula should be within the range of 10mm behind to 10mm in front as an average (across the 2pm to 4pm component of the downstroke) to the 5th metatarsal head.
Ball of the foot should be on the pedal spindle, (except sprinters who need their clips on their toes)
5th metatarsal head should align with centre of pedal axle as the riders natural rate of plantarflexion within the downstroke.
Cranks were associated with height.
Measured hip flexion to reduce the stress on the hip flexor while also maintaining leg extension/leg flexion range between 70 and 75 degrees.
Back nice and flat.
Neutral spine inclusive pelvic rotation without compromise or curvature.
Make sure your handlebars obscure your front axle.
Reach (between greater trochanter-acromium- styloid process of the ulna) between 80 and 90 degrees.
Torso as low as you can bear and still ride the drops.
Torso (greater trochanter to acromium) at between 35 and 50 degrees to horizontal depending on hand position and spinal postural capabilities.
You can see that in the basic form, the year 2000 version of bike fitting was actually not inaccurate, but the range of placement was very broad because the definitions were broad.
New systems that measure all of the angles and placement have not reinvented biomechanics, but they have made available high accuracy and tighter tolerances. This new-found accuracy is easily defamed if the method of measurement and the points measured to and from are inaccurate which is why making a point of clearly checking and rechecking the placement of your measurement markers through the process to ensure they have not moved.
The newfound niche that is “Professional Bike Fitting” are professionals dedicated to understanding the relationships of each angle and the effect of compromising in one aspect to improve another which is key to the preferred result. The final position is a result of the diagnostic process, and key goals and outcomes as outlined at the beginning of a fit.
No different to the bygone era, the best people are the ones who can have the most inclusive overview of the athlete and the result. Specific goals that align with the best treatment for the client.
In setting the position for a new client, the practitioner forms a prescription of angles that compensate for or align with particular necessities, and we would call the first position a datum-position or an initial position. The difference between a particularly good fitter and an average one, is the negative side effects of the prescription. Like any doctor, getting the dosage of compensation right, and adjusting the prescription may be necessary.
From the data recorded and the new side effects of the initial position, modification can be systematic. Progress can be measured. It is entirely possible (as with any clinical science) that the client does not react as expected to the prescription, but through a symptomatic review the ailments can be adjusted for as time goes on.
The specificity makes it easier to adjust systematically, but the machine doesn’t do it on its own, all it does is outline the operating angles, and the practitioner in their wisdom then applies the prescription based on their experience and education.
So with this in mind, the same train of thought should go through your head as it did when I was a boy. Align yourself with the best experience you can, and no matter what technology is available, the need for experience will never change.
