Wednesday, July 31, 2013

Bike Fit/Seat Height

Cycling and swimming are more complicated than running.  Lace up your shoes and head out.  We have been opining about form recently, but this is a recent obsession by a bunch of us who had been running for decades before we started worrying about heel strike/forefoot/midfoot strides and hip rotation.   Swimming has less gear, but small form breaks can have major consequences.  On the bike setup can make major differences, but every body is different.

Max has commented on Chris Froome's awkward position on the bike.  Lance Armstrong and Jan Ulrich had markedly different pedaling styles, though both were the best of their highly juiced era.

When I had my tri-bike fitted, I went to an extraordinarily talented fitter who prays at the altar of steep.  His goal is to set you up in the most "aggressively aerodynamic" position that you can hold comfortably.  I can't really argue with it.  At the group workouts I've attended, I've been among the faster riders.  At yesterday's workout alternating 3.35 mile laps hard and easy, I averaged 23 miles an hour for the hard laps. For folks who know Prospect Park, my fastest lap was 8:38.  My slowest 8:41.

But, and this is a big but, the setup has the seat at the high end of high.  This gives me a lot of power, but it also seems to be bothering my hip.  My road bike setup is considerably less agressively, with the seat lower and further back.  Instead of pulling up on the clips, I tend to pull back with my hamsgtrings.  This leads to a quicker cadence, less powerful stroke, but no kink in my hip.

The place where I really noticed the difference was on the spin bike.  Spin bikes never fit right.  The height adjustment is in 1/2 inch increments.  So, when I tried to set up the spin bike to match the tri bike fit, I lost my spin.  Last week I went back to my old setup, again, lower and further back.  All of a sudden everything feels better (including, knock wood, my heel a bit).

I'm wondering if I should drop the seat a hair on the tri-bike . . .


  1. Can you post a picture in profile of you in the aero position, or better yet a brief video to Youtube? I'm a reasonably good (and certified) tri bike fitter, and I'd be happy to have a look. Generally an aggressive tri bike fit is not obtained by raising seat height unless it is too low to begin with; there is a physiologically correct seat height for any given seat angle. If your tri bike fitter raised the seat in order to get a more aggressive position, that's mildly disturbing.

  2. My present to myself next week is a proper bike fit in a space adjacent to my friendly neighborhood bike shop.

  3. Damon does know his stuff on bike fit. On the other hand, seeing what he rides scares me.

    In _very general_ terms, you accomplish approximately the same body position on the tri bike that you do on the road bike, but rotated forward some number of degrees. Saddle height does not change (your legs are a fixed length) but the hands drop down and the saddle moves forward. The saddle may tip a tad forward as well.

    Riding a road bike in a triathlon should therefore become uncomfortable when you try to drop into the aero position because you become unnecessarily compressed due to the rearward seat position. In fact, when I ride my road bike on the trainer, I can't hold power over the top of the pedal stroke; I'm literally relying on the momentum from the upward motion until I get back on the down-stroke.

    To my lights the most likely culprit for feeling off in a tri-bike fit relative to a road-bike fit is a seat position that is too far _ back_. If you are dropping your hands toward the ground, you would rather do so with the hips further forward than further back.

  4. Damon, we're talking about maybe 1/8 of an inch here. We did a quite thorough ergonomic fit, on an infinitely adjustable bike/bench, with a video analysis of my mechanics. And, let's be clear, I have not had any trouble staying in Aero on the bike during an Olympic Tri, and on 40-50 mile training rides. Also, I'm going very fast (for me at least), both down and, more importantly, up hills. What I'm trying to figure out is whether I'm still adjusting to/figuring out the "tri" saddle (Adamo), or whether I need to drop it a hair, or tip it a bit forward.

    When I'm in Aero, and I remember to really allow myself to tip my hips forward and slide to the front of the saddle, I feel very comfortable. But that position feels more like I'm leaning on the saddle than sitting on it. When I'm not in Aero, and sitting up on the saddle, I definitely feel a bit hyperextended. I'm not in that position very much, though. The tricky part is that sometimes, even in Aero, I find myself naturally sitting a bit higher on the saddle and when that happens my pedal stroke slows and I'm not as smooth.

    Anyway, I'm going out for a brick tomorrow, and I'll see if I can get somebody to snap a pic.

  5. No picture. The club coach left before I did (bonus laps). Interesting workout. Warmup lap (3.35), 20 minute run, easy bike lap, 15 minute run, easy bike lap, 10 minute run . . . The run legs were supposed to be hard, but since it was my first run in weeks, I focused on keeping it comfortable. The running went well, considering. Heel/Achilles was not perfect, but seems none the worse for wear now. My hips were tight, per discussion above, but loosened. I experimented with position on the bike, and with position/cadence combinations. Nothing definitive, though.

  6. Are you doing bike-specific stretches? I like the one where you lie face down with the tight leg under you across the body, heel by the opposite hip. Another is lie on your back, legs bent; tight leg crosses other with ankle just above knee; grab shin with both hands and use the one leg to sttretch the other hip.

  7. I do both of those a lot!! The first one was only recently added to the repertoire (about a month ago), but it's now in regular rotation. Another two that are really helpful for opening up the hip are: (1) lunge position, back knee on the ground, slide front foot forward as far as possible (back foot as far back), while keeping front knee directly above front foot; (2) using the a bed or high couch, lie face down with one foot on the floor in lunge position and the other leg resting on the bed couch, grab the trailing foot at the ankle (bending the knee) and bring it as far forward/up as you can.

    The second one is a hard position to get into. I find I have to hold the back ankle before I lean forward, but it's an amazing stretch.

    Anyway, the thing I'm trying to work out, and this appears to be "me" specific, is how much bend I need to leave in my knee before I start torquing my hip. There seems to be a very specific spot. I have felt it when tweaking the saddle position on my road bike, and when we were doing the bike fit for the tri bike. When I fin that spot, I get both a very natural spin, and a lot of power. Too low/far back and I lose power. Too high/forward and I get power but annoy my left hip.

  8. There is a lesson about individual uniqueness, isn't there. As you said in the post, when running you can micro-adjust on the fly. When biking the adjustments are more difficult and, when completed, semi-permanent.

  9. Yes. On my road bike I don't have any qualms about hopping off, getting out the Allen wrench and trying an adjustment (at least when I'm not trying to keep up with a group). I don't yet feel quite so empowered on the tri bike.

  10. Today I got inspired to tweak my road bike saddle placement. I shortened my stem in the off season, and that changed the ergonomic package a bit. I've gone out for medium sized rides (45 and 60 miles) in the last few days and it wasn't feeling quite right. Shifted saddle back a hair, and tipped it slightly forward. That seemed to do the trick.