by Greg Pelican
Power meters have become a mainstream training tool for serious cyclists and triathletes. The price has come down and there are many variations and manufacturers. Garmin’s third generation Vector 3 pedals not only offers a great lightweight pedal and flexible solution for power, but also includes Garmin’s Cycling Dynamics which open up a whole new world of useable ride data.
This bog post explores the untapped potential of Garmin’s Cycling Dynamics.
As a techie, racer and bike fitter the potential use and application of Garmin's Cycling Dynamics fascinates me. Yet when I search for relevant research from coaches of how this is being used I found next to nothing. The truth is that the technology is still so new there is not much out there.
Cycling Dynamics provide great info you can see real time on a ride or post ride:
A member of our Segafredo-Trek Tri Team, Grace Plager, was advised by her coach to see me for a bike fitting after experiencing pain and loss of power in her left leg at Ironman UK. Despite her bike issues Grace had a fantastic race and qualified for the World Championships in Kona this Fall! I was excited to help her out.
I knew Grace from the club but never had worked with her as a bike fitter before.
When I put her Trek Speed Concept on the trainer I noticed that she had Garmin Vector 3 pedals. This got me thinking... I asked her if she had her Garmin file from the Ironman race. She did! Grace even told me she noticed during the race that the "PPO" screen (Pedal Platform Offset) was way off. Very interesting! I was wondering about the left to right power balance as well. When I reviewed the Garmin Connect file the average PPO for the left was +1.1 mm (towards outside of the pedal) and for the right -4.1 mm (towards the inside) . The average power data was also skewed at a 48/52 right bias.
When I dug deeper into the Garmin Connect file (see charts above) the actual data fluctuated a huge amount so the average didn't tell the whole story. When I compared the PPO standard deviation from Grace's file to one of my own it was over 3X greater. There were many points greater than 10mm off the center axis for both her left and right leg. Her left to right power shifted much more than the average too, and the trend for both power balance and PPO got worse deeper in the race.
Next I had Grace ride on the trainer both and observed that her seat was very high and she was rocking her hips and reaching at the bottom of pedal stroke. Motion capture and measuring with a goniometer confirmed that the seat was high. We were able to replicate the PPO data from the race, and she felt pain in her left knee.
Now here is where it gets interesting...
I lowered the saddle to the correct height and had Grace pedal. With the seat at normal height the PPO went to the center for both pedals! After looking at the Garmin file, before seeing Grace ride, I was suspected this might be a cleat position problem that could be solved by moving the cleat. But clearly that wasn't the case or the solution!
When her seat was high Grace was rocking in the saddle which caused the uneven pressure to the pedal, and wide fluctuations. It is likely that when she experienced pain in her left knee she shifted her position on the saddle to minimize the pain, and this also shifted her pedal platform offset.
This story has a happy ending! The changes I made to Grace's bike setup resolved her pain and comfort issue and she is again training hard for Kona! And for me I was able to use a new tool, Garmin Vector 3 and Cycling Metrics, to quickly pinpoint and resolve a fitting issue. What was unique was to be able to use hours of race data to better understand the cause of the problem and get real time data feedback in the fitting studio to confirm the solution.
My brain is now wondering how oval Q rings effect the position and length of the Power Phase when pedaling. But I digress, this has nothing to do with Grace, I'll save this for another blog!
In closing stop by one of our 8 stores and check out the new Garmin Vector 3 pedals. I highly recommend them and Cycling Metrics as an excellent training and racing tool.
CONGRATS GRACE AND GOOD LUCK IN KONA!
by Greg Pelican
Over my breakfast coffee I was thumbing through Bicycling's Buyers Guide and read a review on a Canyon road bike. It was the typical great review (it seems that all bikes they write about are awesome), but what caught my attention was the magazine's blurb about the online brand's "Perfect Position System".
Interesting, as a bike fitter I wondered how they factored in the rider's flexibility or core strength. Seat height is fairly easy to get close with a good inseam measurement, but the perfect bar height and reach are very much affected by the rider's experience, flexibility, age, core strength, and of course their anatomy dimensions.
So I went to Canyon's website to see if their "Perfect Position" matched my bike's position which I have honed over many years of riding.
First it had me pick the bike type, bike model and bike spec. Next I entered my gender, weight and 5 body measurements. There was no explanation of how to take these measurements (for example where does the torso measurement start and end) so I used the practice defined by the old "Fit Kit".
The "Perfect Position System" answer was a bike size that isn't even close to what I ride. The top tube and cockpit reach was short and the drop from the bars was extreme. The bike size was too small. My current road bike is well proportioned (see pic lower right), has a reasonable drop, especially for someone 59 years old, is comfortable and fast. There is no way I could get comfortable on the bike size which was recommended.
When finding the perfect bike size and setup, there is no substitute for a experienced bike fitter, and no substitute to getting on a real or fitting bike to determine the optimum position. I find this especially true when fitting older cyclists or riders who are coming off another type of bike such as a hybrid and buying their first road bike.
At Trek Bicycle Stores of Florida we start with taking body measurements, and then get the cyclist riding on a trainer on a real bike. From there we adjust the position based on the rider's flexibility, core strength and feedback. This often requires a stem change, and sometimes a bike size or model change before everything is dialed in perfectly. I often give posture tips and make a video of the customer riding to help reinforce the proper posture and position.
In person bike fitting is a great no-charge added value that we offer with each road or tri bike purchase. Come on in to one of our stores to truly find the Perfect Position and Perfect Bike!
Proper bike fitting is essential to comfort, efficiency and speed on the bike.
I've been bike fitting for 18 years and have helped thousands of riders get set-up on new bikes, or optimize their position of current bike.
Ironically the biggest fitting problems often exist with cyclists who want to go the fastest.
It is easy to fall into the low = fast trap. Slam the stem, put the bars as low as possible and look "pro". But if your goals are a bit broader than looking "pro", if you want to feel strong, comfortable and race FAST read on...
The ideal bike fitting is one that is optimized for all of the following factors:
Finding the balance between these factors takes experience, good feedback from the cyclist and real world trial and error to see what your body can tolerate.
It is true that you can reduce drag (and improve speed) if you can ride in a lower and /or narrower position on the bike, but there is a limit for everyone. If the position is too aggressive your aerodynamics could end up being worse. This will happen if you can't stay in the aero bars or ride in the drops for a road bike for the race duration.
Another possible negative effect of having the bars too low is that your hip angle could be so closed down that you can't generate your full power potential, often this causes other side effects such as rocking of the hips or the cyclist's knees splaying out (appearing bowlegged) which of course results in increased aerodynamic drag. And trust me, if you are a triathlete or duathlete it is not easy to run fast off the bike if your back or hips are tweaked.
A little over a year ago I did a bike fitting on Ross Lenehan who is one of the top triathletes in the region. Ross is an outstanding runner in excellent shape, but he was uncomfortable on his tri bike and couldn't ride for extended periods.
When observing Ross ride, his leg was almost fully locked out at the bottom of the pedal stroke causing his hips to twist down. The reach to the bars / pads was also too which far which caused tension in his shoulders, neck and arms.
During our bike fitting session I lowered the saddle, moved it forward to increase the effective seat angle (resulting in a less acute hip angle), and used a shorter stem to decrease the cockpit reach. All of these things made Ross not only more comfortable but fast. He ended having a great season! Ross earned USA Triathlon All American honors and was the overall winner at the Fitness Challenge in Naples and Captiva Island Tri.
Ross is off to an awesome start in 2017 racing for our new Trek-Segafredo Tri team. He finished 5th Overall at Ironman Florida 70.3 in 4:11 averaging 25 mph on the bike leg followed by an impressive 1:20 half marathon. Ross followed that up with a 4th place overall in the open category of St. Anthony's Tri.
We wish Ross much success! Meet him in the following short video.
Don't hesitate to email If you have questions about bike fitting or want to schedule a fitting. See you at the races!