Question for all the fit gurus. I notice that on many threads where people post a critique my fit pic, people comment on seat height. That is fine, I understand the ST running joke.
However, it seems people use foot or ankle angle (i.e., parallel to ground at lowest point of pedal stroke) as a proxy of the correct saddle height. Every study I have read, seems to indicate that this metric of seat height is not used. From what I can gather the best metric is measuring the knee angle and it should be between 25-35 degrees.
When I have done this on my own, my seat height leads to a toe pointing ankle angle. I have read that a knee angle of 25 degrees puts less strain on the patella, and I have an issue with patella tendenitis, so I set my bike up with a knee angle of 25 degrees.
Also, when I look at many pros there are some with the flat ankle angle and some with a toe pointed angle. It also seems to me that ankle angle should vary with steepness of seat.
Am I missing something here.
In the abstract, with a seat that is too high what are the negatives versus too low.
Is the flat foot (ankle angle) just wrong as a proxy of good fit. i.e., it may look good and powerful on a picture, but may be suboptimal in reality?
You say you’re setting your position up for a 25* knee angle. How are you measuring this? Is someone else using a goniometer on you? What markers are they taking the measurements from?
Ok, but 25 seems kinda high to me. I generally shoot for 30-35. Downsides to a too high saddle can be excessive movement or dipping of the hips if your hams and saccrum(sp?) can’t comfortably reach. Less efficiency through the lower part of the stroke. A high ankle is just a red flag that the saddle might be on the high side. It might work for you. For others it might lead to tight calves. So many variables to this stuff. Especially without actually being present when you’re on the trainer.
Downsides to a too high saddle can be excessive movement or dipping of the hips if your hams and saccrum(sp?) can’t comfortably reach.
Thread Highjack…
If you don’t rock your hips will this problem manifest itself as High Hamstring Tendonopathy? I ask because I have always run with my seat higher than suggested and recently I have run into this problem when I ride my TT bike. Riding my road bike with the club doesn’t cause the problem. Seats are nearly the same height, but on the road bike I am up on the hoods most of the time, on the TT bike I can (and do) ride in the aero bars for hours.
I thought it was over training, but your comment got me thinking.
Hmm, I’ll give a general answer since I’m not qualified to address High Hamstring Tendonopathy. If I understand it right, you are running generally the same seat height on both your tt and road bike. Assuming you don’t have a super aggressive cockpit on your road bike, your torso angle will already be greater than on your tt bike. You ride on the hoods most of the time, which probably gives you even more torso angle.
I forget the specific muscles but there are groups that connect the upper inner femer to your sacrum and lower lumbar. So the torso angle actually affects some muscle groups in the leg, including hamstrings; not just the low back. A more upright torso stretches those muscles less than a tt position. So yeah, if you’re not having problems with your road bike, you might try opening up your torso angle on your tt position. Either by lowering your saddle (since you already said its higher than suggested) or by raising the cockpit. Or both.
Now I don’t claim to be the best fit expert in the world so I’m sure you’ll hear some other valid suggestions that differ than mine. There are so many other factors not taken into account here. For people with specific chronic problems like yourself, I often like to get a PT involved. If you haven’t been fit by a reputable professional, I’d save up and do that. Its worth the money.
I would agree with the last poster on lowering your seat a touch. I have been having the same issues with my hamstring and generally have had my road and TT bikes set up the same. I don’t ride steep so it makes transferring the numbers easier. One thing I noticed was a recent John Cobb video where he shows how the TT position raises up your hips as soon as you go from sitting up to aero position. Because of this a lower seat height works for me and has made a ton of difference. You might want to google the Cobb video or check it out on Facebook as I think I found it there.
Often times the body tries to preserve “knee angle”, meaning that it tries maintain similar knee angles as saddle angle is changed.
It achieves this by pedaling with more or less toe point.
Seat too high / knee too open? Point toe down. This will effectively close your knee angle down.
Seat too low / knee too closed? Point toe up. This will effectively open your knee angle up.
Obviously this is not 100% tried, true or reliable. It just happens to be the general pattern.
It sounds, from your description, that your body is fighting the knee angle that you are trying to set it in. You are achieving that knee angle by going far outside your body’s comfort zone. As you reach the extremes of your range of motion, the knee angle will eventually have to change.
I am passing no judgement as to whether this is a good thing or not. I don’t know what your knee angle ought to be without evaluating you.