Comment of the week: A brief intro to bike fitting

Getting fit with Seth Hosmer-4
Getting fit.
(Photo: J.Maus/BikePortland)

Jonathan’s very personal post last week about recovering from his recent knee injury with the help of a local chiropractor prompted some useful and impressively respectful discussion about the lines between physical therapy, chiropractic care, training and health care in general.

But as a relatively casual rider who’s starting to feel the first persistent aches of my 30s, I was especially interested by a comment from a reader named David, who offered a simple, compelling introduction to the practice of bike fitting.


Bicycles have substantial bilateral symmetry. Humans, not so much; we just look that way.

Well fit, a bicycle [is] like a good pair of shoes, you don’t notice and go all day. Poorly fit, you notice.

If the fitter doesn’t squat down and watch you from all angles, at least from the four sides, go somewhere else. A good fitting takes more than one session.

Fitting has gone through three major approaches:

Anatomical, measurement, bio-geometric, formula measure lengths: the rider’s arm, leg, torso; do some math; adjust the bicycle. Epitomized by FitKit, important at the time. Improved by a goniometer to measure angles: knee, torso, arm. All static measurements. Few humans fit well any set of numbers.

Bio-mechanical, dynamic measure movement, usually with motion capture. Informed by sports-med. Improvement over bio-geometric. Still limited by an idea of correct position. Exemplified by Andy Pruitt. (Andy does good work but his book disappoints). This approach comes with a lot of technology and theater.

Neuromuscular adjust bicycle to rider’s current ability. Measure the rider’s range of motion off the bike, especially noting asymmetries of flexibility and strength. Adjust leg extension based on velocity of knee. Adjust handlebars based on strength and flexibility of back. Adjust torso position to improve cardiovascular performance. And many more details. Epitomised by Steve Hogg.

Good fitting starts at the feet.

Mindfulness makes the biggest difference. Every so often, for a few minutes out of every half-hour, pay attention to how you ride, how you feel, how you move, how the bike feels under you.

(Steve Hogg has a somewhat different analysis and goes into much greater detail, highly recommend you read him. )

Elsewhere in the same thread, reader daisy describes her own experience getting a fitting, which is available from nearly every local bike shop.

For all of us looking forward to many years of using biking to keep our bodies strong and limber, David makes a pretty good case that a bike fitting is worth considering.

Yes, we pay for good comments. We’ll be mailing a $5 bill to David in thanks for this great one. Watch your email!

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