Bike Fitness Coaching is now a IBFI (International Bike Fitting Institute) level 3 fitter and our newest “INTERNATIONAL REMOTE-BIKE FITTING” client heard about us through this great organization. Jacques is 60 years old and a life-long cyclist from the Hautes- Alpes of France, cycling on legendary mountains such as col du Tourmalet, col du Galibier, alpe d’Huez and even the 20% grades of La Planche Des Belles Fillesalso. He has family in the US near our shop, so he thought to contact us before his holiday trip to the US.
Now that he’s retired, he’s putting in more miles on the bicycle and, along with more miles, more knee pain.
After several Skype sessions, he has sent me some video to analyze. I chose 2 frames, one at max flexion and one at max extension. He likes to wear tennis shoes on local rides but wears cleats and cycling shoes on his other rides.
After my analysis, here’s my reply.
“Jacques, looking at your photos, here are my recommendations;
- Your 170mm crank arms are at the maximum length for you. 165mm would be much better for you.
- You are a little low in the saddle. The ‘safe’ range is 144-152, with 150° being optimal, you are 132.3°. Raising the saddle will also ease your 68.6° knee angle which is currently contributing to your knee pain. I would start with adding 2-3mm saddle height.
- The tennis shoes you are wearing have a larger stack height when comparing to actual cycling shoes. Therefore, for more accuracy, I would prefer to see you wearing your cycling shoes and resend the videos.”
- Your arms are outstretched and should be bent slightly at the elbows. This tells me that the stem is a little long – currently looks to be about 110mm? I recommend an 80mm stem if your stem is currently 100mm, or a 90mm stem if your stem is currently 110mm. I would stay with the +/- 17° rise option and keep it in the + position.
So, ultimately, shorter 165mm crankarms would be a much better choice, but Jacques can still ride the 170’s, if he raises the saddle. He might still experience some residual knee pain with the 170’s but, with the 165’s, his knee pain should disappear.
Max Extension vs Max Flexion work in conjunction with each other. Max Extension is dictated by saddle height, while Max Flexion is dictated by crank arm length. The objective is to determine the correct crank arm length so that the client will not experience any knee pain. This is why I recommended 165mm crank arm length for this cyclist.
I uploaded the video into Dartfish 9, then went to the Analysis screen. From here, I found max extension and placed 3 markers, one on each pivot point; Greater Trochanter, Lateral Condyle, Lateral Malleolus. Then, I chose the angle tool to determine the angle between these pivot points. I made a screenshot, then found his max flexion and associated angle.
We at Bike Fitness Coaching can help you with your bike fit. Our newest service is called “Remote Bike Fit” where we walk you through the process of taking a could videos then analyzing them and recommending changes. This has been an exceptionally successful service for those cyclists living in remote areas where bike fitters are rare or non-existent.
Rick Schultz, MBA, DBA
bikefitnesscoaching@gmail.com
www.bikefitnesscoaching.com
USA Cycling Level 2 Coach
Peaks Coaching Group Coach
Certified Power Based Training
Certified Skills Instructor
Beginner Racer Program Instructor/Coach
Certified Bike Fitter, IBFI Level 3.
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