For example, Mike came in for a
basic hour-long fit session. His main concern was that he was experiencing high
saddle pressure. So the session focused on dialing in his position and
choosing the right saddle using saddle pressure mapping. He is riding in
comfort now and is pain free, a great result.
We had Mike come back in for a
follow up session and explore more options for perfecting how he is getting
power into the pedals. Turns out Mike never really had his cleats setup
before, he is using a non-cycling orthotic inside his shoes, and 3mm of cleat
spacers had been installed on his right shoe because of what he had been told
was a leg length discrepancy. All of these issues alone could contribute
to some shoe/pedal problems, and all of them together are almost certainly
going to raise concerns.
After getting Mike setup with shoe
pressure mapping, we captured a baseline measurement.
Mike's Baseline Measurement
Immediately a few issues appeared
-- a relatively small area of the shoe is absorbing pressure; on the left,
almost all pressure is on the big toe and the ball of the foot; pressure is
relatively low; pressure is quite unstable; and, critically, the left/right
distribution (the red wave is left pressure) shows relatively little pressure
is making it onto the left shoe. The result is all of this is that
although is saddle pressure was massively improved the multitude of issues with
his shoe and pedal setup left the critical point of power transfer with room
for improvement.
Mike has medium height arches but
they collapse significantly under load. To correct this, the first
intervention we made was to replace his insoles with cycling specific
insoles. This included better arch support, and also allowed his heel to
fit more snugly into the back of the shoe. The results of the next pressure run
are significant: Pressure is distributed over the transverse arch of the foot;
peak pressure went up meaning force to the pedal went up; stability improved
with more pressure concentrated on the forefoot; and pressure on the big toe
went down.
Mike's Insole Pressure
At this point, however, things are
still not perfect -- pressure is still too high on the ball of the foot for the
right side. We noticed a forefoot varus on the both feet, and guessed
that without support, the ball of the foot was collapsing inwards creating the
pressure visible in this picture. Mike has a varus on both sides but his big
toe on the left foot is pointing down quite a bit and pressure on the left
appears to be good without that extra support.
Post-varus correction, the right
foot is much more balanced, with the pressure peak on the ball of the foot
disappearing. At this point, we are close but his cleats still had not
been setup. The ball of the foot was actually set so that it was in line with
the pedal spindle, resulting in pressure that was too far forward on the
shoe. And it turns out that Mike’s cleats were actually as far forward as
they could go. We moved his cleats back 1cm and ran foot pressure one last
time.
Mike's Final Measurement
Pressure is balanced across the
center of the forefoot and, most significantly, left and right pressure have
similar force curves. More balanced, more stable, more powerful.
Using foot pressure in the context
of this fit provided the critical last bit of data to help ensure that the
changes we made were translated into more force on the pedals. As we can
see with Mike, adding a foot pressure component to a bike fit is critical for
ensuring optimal performance.
