Who is Andy Pruitt?
Andy is the founder of the Boulder Center for Sports Medicine, in Boulder, Colorado, and a specialist in non-surgical techniques who has treated athletes like cyclist Lance Armstrong and Floyd Landis.
What the pro's have to say about Andy:
“Andy Pruitt is one of the most knowledgeable people I know when it comes to the physics of cycling and how the human body adapts and changes through years of cycling. With that knowledge he has the potential to help a lot of athletes get better.”
Floyd Landis [no less], Team Phonak
“Thanks to Andy my strength on the bike has increased a lot. He improved and optimized my position on the bike to produce more power, placing less strain on my back, hamstrings, and knees. His expertise will help you get as much out of your bike rides as possible.”
Gunn-Rita Dahle Flesjå, world champion mountain biker
Much has been written about Bike Fit and there are many opinions and views. Andy Pruitt talks a lot of sense here, much of what he says is based in medical research and working with riders with 'issues' and those who need to adjust their training and bike fit specifics.
The Complete Medical Guide for Cyclists is published by VeloGear and available from www.amazon.co.uk
We're very pleased to get this extract... so enjoy.
RULE 1: BIKE FIT IS A MARRIAGE BETWEEN BIKE AND RIDER
When I give talks about bike fit to physicians or cyclists, I often use a photo
of a cyclist dressed in wedding garb with his bike on the steps of a church.
It's a visual way of reminding people of the importance of compatibility between
bike and rider. Marriage is a strong metaphor for the partnership of
human and machine but it's an apt one. In fact, serious riders may spend
considerably more time with their bikes than with their spouses!
If you and your bike are incompatible, the marriage will fail. Just as
married couples must adjust to each other, so must a bike and rider.
However, a bike can be adjusted in multiple ways; the saddle can be
moved up or down or the stem can be changed to suit the anatomy of the
rider as needed. But the body can be adjusted only in minor ways—with
a carefully designed stretching program and by adapting to progressively
longer rides. This leads us to the second rule.
RULE 2: MAKE THE BIKE FIT YOUR BODY - DON'T MAKE YOUR BODY FIT THE BIKE
It's easy to adjust a bike but difficult to stretch or contort your body into
some preconceived “ideal” position. Therefore, it's important to focus on
making the bike fit you, rather than you trying to match the way another
cyclist rides. For example, if you have long legs coupled with a short torso
and arms, your bike should have a relatively short top tube and stem combination
(often called “reach”). But if you have stubby legs and most of
your height is in your torso, you need a long top tube and stem.
Many riders get their idea of perfect fit from watching pro riders in
person, in videos of races, or in magazine pictures. Then they try to emulate
riders they admire. This is a bad idea for many reasons. Pro riders are
usually lean and lightly built. If you're not quite as svelte, it's hard to get
as low and aerodynamic as a pro who isn't bending over a middle-aged
paunch. Even a fit and lean 50-year-old is probably not as flexible as a
130-pound, 22-year-old professional rider.
The pros are also generally quite flexible because they've been riding
competitively since they were young. Their bodies have had time to
adapt to extreme positions that result from the handlebars being much
lower than the saddle.
Finally, pros compete in as many as 100 races a season. Much of their
riding from February to October is spent at the intense levels required by
racing. It's easier to maintain a low and aero position when going hard;
much more difficult when cruising at a recreational pace. When you cycle
hard, pedaling levitates your body slightly off the saddle and you lean
over into the effort. But when you're cycling at a moderate pace, you
tend to sit up, which puts pressure on your hands and your seat. As a result,
you'll feel poor fit faster than the hardworking pro.
So forget what your favorite pro rider's bike looks like unless your
body and your riding style are carbon copies of his. Make your bike look
like you, not like your hero.
RULE 3: DYNAMIC BIKE FIT IS BETTER THAN STATIC BIKE FIT
Most bike fit systems are static; that is, adjustments are made with a rider
sitting motionless on a trainer or from a set of formulas using body part
measurements. An example is the LeMond Method (see Chapter 2) that
establishes saddle height and frame size from a measurement of the distance
from the pubic bone to the floor.
There's nothing wrong with these static methods of bike fit. Static and
numerical formulas are an important starting point from which we can
move to dynamic fit. But any static formula is only a starting point.
When you are pedaling, you are constantly moving on the bike. As
you pedal, you actually rise or levitate slightly from the saddle. Therefore
the adjustments made when you're sitting motionless will result in a different
saddle height than if measurements are taken while you are pedaling.
Reach to the handlebars can change too. When you're cruising, it's
easier to reach brake lever hoods that are a bit too far away from the saddle.
But when you're riding hard, the hamstrings and muscles in the
lower back tighten with the effort, making the bars seem farther away.
Every rider has experienced this phenomenon of the bike “growing” as
the ride gets longer. It's one reason that while climbing, we tend to sit up
and grab the tops of the bars next to the stem.
At the Boulder Center for Sports Medicine, we use a dynamic system
to determine bike fit variables such as saddle height. First, we attach
reflective markers to specific anatomical landmarks on the rider's knee,
ankle, and hip (see photo). Then we put him on the trainer and have
him pedal.
We use movement-capture hardware and software to take pictures of the
pedaling rider. The camera emits infrared light to pick up light from the reflective
markers, which are sensitive to infrared. A computer converts the
rider into a 3-D stick figure. From that data we can determine exact and
functional fit for saddle height, saddle fore/aft, and reach to the bar.
When we first developed this system, all the computerized information
had to be entered by hand. Additionally, the bike frame got in the
way of the leg farthest from the camera so its position had to be inferred.
It often took hours to get the data. But now the technology is much
more sophisticated. Results are essentially instantaneous. We can have a
rider converted to a pedaling stick figure almost as soon as she is off the
bike. Finding the ideal bike fit now is just a matter of minutes, rather
than hours.
Again, there's nothing wrong with static bike fit and mathematical formulas
as a starting place. In fact, in this book I'll suggest a number of
ways to find ballpark figures for these important measurements. For 95
percent of riders, the information in this book will enable powerful and
pain-free cycling. But if you're constantly uncomfortable on the bike or
beset with nagging injuries, there's no substitute for an anatomical dynamic
bike fit done while you're actually pedaling.
RULE 4: CYCLING IS A SPORT OF REPETITION
A basketball player probably won't get an overuse injury from shooting.
Even if he hogs the ball and puts it up every time he touches it, that
probably results in only about thirty repetitions of the shooting motion
in a game. And once his teammates are on to him, he probably won't get
the ball as much!
But cycling, by its nature as an endurance sport, demands continual
repetition of the same pedaling motion for the duration of the ride. At a
cadence of ninety revolutions per minute, a six-hour century ride requires
32,400 iterations of the pedal stroke for each leg. That's a lot of repetition!
Worse, each pedal stroke is almost identical. Your knee tracks in the
same plane when observed from the front, and it bends the same amount
at the top of each stroke. As a result, a minor misfit (for instance, having
the saddle too low by several millimeters or having one leg longer than
the other by just 5 mm) can lead to major problems over time. That's
why fit is so important.
Cycling's repetitive nature manifests itself in the areas of hydration and
nutrition too. Training requires about 600 calories per hour and racing
may burn upwards of 1000 calories per hour. The best conditioned rider
can store glycogen for only two hours of hard effort. This means that only
halfway through a century ride, you're dehydrated and malnourished! It's
not just your connective tissue that suffers on long rides.
RULE 5: REMEMBER THE FIT WINDOW
There is a window of good fit on a bike for each rider. I don't want to
make bike fit sound like a matter of millimeters. Everyone is different,
and even with all my experience I can't tell you exactly how high your
saddle should be or nail precisely your best reach to the handlebars without
much study of your particular situation.
Most standardized bike fit systems will get you within 2 cm of this fictional
“perfect” fit. At the Boulder Center, we can get a little bit closer.
But over time your body will lead you to make adjustments that bring
you within this “fit window” of a centimeter on either side of your virtual
“perfect” measurement. If you are presently comfortable on your bike,
that's great. If not, keep working at finding a better position.
RULE 6: MOUNTAIN BIKES ARE AN EXCEPTION
These rules apply to road bike riders as well as people who ride a mountain
or hybrid bike on the road. When riding on a road, your position
stays relatively the same, and you spend a low percentage of the time out
of the saddle. Therefore, repetitive forces are high when riding on the
road.
However, riding a mountain bike on technical terrain like rough singletrack
or rocky four-wheel drive roads lessens the repetition somewhat.
Instead of pedaling with the same motion for hours, you're bouncing all
over the saddle, standing to get over obstacles, and descending with the
pedals horizontal while using your arms and legs as shock absorbers.
Because of this, fit on a mountain bike is a bit different from fit on a
bike ridden predominantly on the road. For instance, many off-road riders
like their mountain bike saddles about 1 cm lower than they set seat
height on their road bikes. The lower saddle provides a bit more power
for high-torque climbing and makes quick dismounts easier.
But remember the “fit window” of 2 cm. Even if you ride off-road exclusively,
getting a good road fit helps. A good road fit can serve as a baseline
reference. Then you can make modifications for riding off-road from
a solid starting point.
A few more 'fit specific' tips when buying a bike:
Saddle position
Saddle position is the key fit variable and the most
important measurement to get right. Both saddle height and saddle setback
are important.
Frames
In the past, frames were designed to allow a large gap—as much as
three inches or more—between the handlebars and the top of the saddle.
Now we've come to realize that bars set higher, sometimes almost even
with the saddle, can improve comfort and power production without
compromising aerodynamics.
Layback
It's a fashion statement in some cycling circles to have
the saddle jammed as far back on the seatpost as possible so the
rider can sport what he considers a “pro” position. But this setback
is right only for riders with long femurs and flexible lower
backs and hamstrings. Be sure your saddle height and setback are correct before
you adjust the handlebar.
Level saddle, or not?
Here's the rule: If you're a recreational or touring cyclist and you ride
with the nose of your saddle pointing up or down, your bike doesn't fit.
The reach to the handlebars is probably incorrect.
In general, your saddle should be positioned level with the ground. It
should not be angled up or down. Check it with a carpenter's level or by
placing a yardstick lengthwise on the saddle and comparing it to something
horizontal, such as a tabletop or windowsill.
Fork steerer tubes
If you're buying a new or custom bike, don't let the shop cut
the steerer tube until you're sure the fit [height] is right.
Final fit
Remember that even if you had your bike fitted by someone with extensive
training and experience, that doesn't guarantee the reach will be
right the first time. Because of all the variables that go into it, it's beyond
even the best bike fitter's skills to get reach right on the first try. This dimension
is just too personal because of anatomical variables that are not
obvious to the bike shop fitter.
As a result, don't feel shy about returning to the shop if you realize after
riding several hundred miles that you need a stem change. Riding for
several hours can pinpoint areas of discomfort that weren't obvious in the
shop the first time. Finding the right reach is a precarious balance, and a
good bike shop will understand this and help you get the fit you need.
Bar width
Handlebars come in several widths. Some manufacturers measure drop
bars from the center of the bar ends, while others measure from the outside
of these openings.
Generally, the bar on your road bike should equal the width of your
shoulders, using the center-to-center handlebar measurement.
Stay safe
You may see some roadies try to get more aerodynamic
by resting their forearms on top of the bar. They grasp the
cable coming from the side of each Shimano brake/shift lever. This
is extremely dangerous! The cables provide only a flimsy grip, so
hitting a bump can cause loss of control and a nasty crash.
Change positions
No matter which grip you use, remember to change it frequently.
If your bike fits properly, holding the bar tops will be as
comfortable as riding in the drops. If you are comfortable only with
your hands in one location, it's a sign that your reach to the handlebar
is incorrect.
Stem length
Some riders install a long stem with the bar much lower
than the saddle, thinking that this makes them look like a pro. But
the reach is often so excessive that they have to ride most of the
time on the tops with their hands next to the stem. Then they have
to move their hands each time they want to brake or shift.
Modern brake/shift levers are designed to reward riding with the
hands on the lever hoods, where both shifting and braking are
readily accessible. This is, to use a computer term, the default position.
Still, it's best to change your grip every few minutes to avoid
hand numbness.
Hot foot?
Drilling shoe soles is a last resort. Don't try it until
you've exhausted the other remedies for hot foot in this book.
Drilling can ruin expensive shoes if you don't know exactly what
you're doing. In some soles, drilling additional holes can weaken
them. Also, moving cleats far to the rear may reduce “hot foot”
symptoms but create other physical problems as the body copes
with the extreme change in position.
Injury aid
Some injuries respond to focal icing—rubbing ice directly on
the exact spot of the pain. Fill a small paper cup nearly full with water
and put it in the freezer overnight. Once it is frozen, gently massage
the afflicted area with the exposed end of the ice, like you're
rubbing it with an ice cream cone. As the ice melts, peel away the
paper cup to expose more ice.
Place a towel under the injury to absorb the melting ice. Stop
when your skin begins to get numb. Several five-minute sessions
per hour up to three times a day should provide plenty of therapy
for your ailment without injuring your skin.
FREQUENTLY ASKED QUESTIONS: KNEES: How should I care for knees on rides?
There are several things you can do to take care of you knees while you
ride:
Keep your knees warm. Riding in chilly temperatures with bare knees
is a recipe for trouble. The knee's tendons lie exposed near the skin's surface.
My rule is to cover your knees with leg warmers or tights if the air
temperature is below 65°F.
Warm up. Your knees need at least fifteen minutes of gradual spinning
to get the blood flowing. Start in a small gear and gradually increase both
the resistance and the cadence until you're sweating lightly and your
knees feel loose. Blasting out of your driveway in the big ring and attacking
the first hill can lead to disaster.
Spin. Keep your cadence between 80 and 110 rpm on the flats and no
lower than 70 rpm when you're climbing in the saddle. If you're standing
while climbing you can go a bit lower, but not much. Low cadences and
big gears are an unholy alliance, putting major strain on knee tendons.
Look at the pros—they spin at high cadences with a pedal stroke that's
silky smooth.
Build mileage gradually. The standard recommendation is to increase
mileage no more than 10 percent from one week to the next. You need to
let your knees adapt to the workload.
Change with caution. You knees are creatures of habit. They don't like
new strains or stresses. If you've been riding on flat roads all season, work
into climbing gradually. If you decide to install longer crank arms, don't
ride 100 miles the first time out on the new equipment. Easy does it.
Copyright: Andy Pruitt/Velogear press
The Complete Medical Guide for Cyclists is published by VeloGear and available from www.amazon.co.uk
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