Power Play
Building tri-specific power on the bike
By Matt Fitzgerald
May 28, 2008 -- Power seems so straightforward.
It boils down to a single number that you read on your bike’s
power-meter display (assuming you have one). But power, as it relates
to triathlon cycling performance, is somewhat more complex, and, regardless
of whether you train with a power meter, you can boost your performance
by including power-related training sessions.
There are three distinct ways to increase power output on the bike:
you can push bigger gears, you can increase your cadence and you can
climb. The ability to push huge gears comes from pure muscle strength,
but this is only part of the power equation. Your pedaling power is
greatest when you’re strong at high muscle-contraction speeds,
such as at 90 RPM or greater (those who are strong at slower muscle-contraction
speeds are better suited to towing fire trucks). In fact, increasing
your cadence at any given gear ratio always increases power output,
but this is beneficial only if your neuromuscular efficiency at the
higher cadence is equal or greater (and there is no one-size-fits-all
when it comes to optimal cycling cadence). Finally, climbing performance
is affected by rider weight. On a flat road, the cyclist who’s
putting out the most power is the cyclist who’s moving the fastest
(assuming equal aerodynamics). But on climbs, it’s the rider
with the highest power-to-weight ratio that gets to the summit quickest.
So there’s no simple answer when it comes to building optimal
power for triathlon.
Doing
it right
Increasing your maximum power output on the bike is unlikely to improve
your triathlon cycling performance and may even worsen it. The physiological
underpinnings of maximum and sustained power become mutually exclusive
after a certain point. Thus, the way to improve your triathlon cycling
performance is to increase the percentage of your current maximum
power output that you can sustain over the race duration.
Given these complexities, what place, if any, should training at
maximum or near maximum power output have in your training? The answer
is that you definitely should do a small amount of bike training at
the upper end of your power range, because this type of training carries
three important benefits. First, it minimizes the amount of power
you lose over the course of a training cycle. It is normal for individual
muscle fibers to become slightly less powerful through endurance training;
however, because their cross-sectional area decreases even more, their
power-to-size ratio actually improves. Doing a little maximum-power
training on top of a lot of aerobic training will boost your muscle
fibers’ power-to-size ratio further.
A second benefit of maximum-power training is that it activates more
muscle motor units than lower-intensity training. Again, when a small
amount of maximum power is layered on top of a lot of aerobic training,
the effect is that your neuromuscular system learns how to make more
total muscle tissue contribute cooperatively to performance at race
intensity.
Finally, maximum-power training, especially when done relatively
early in the training cycle, is an efficient way to prepare your body
to safely handle a higher training workload in the mid- to late season.
Small doses of very high intensity work are relatively well tolerated,
even at a very modest level of base fitness, but they stimulate adaptations
(such as a surge in aerobic capacity and better resistance to muscle
tissue damage) that quickly enable the body to successfully absorb
much larger doses of submaximal exercise.
Boosting max power
Training at your maximum power output level is a fairly simple matter.
It requires that you turn the cranks as fast as you possibly can against
heavy resistance for no more than 20 seconds at a time. The heavy
resistance can come from a hard gear or a steep hill.
In the early base phase of training (or if you have returned to a
short late-season base phase before beginning your final build of
the year), throw a smattering of power intervals into one or two endurance
rides each week. It’s good to do a mix of high-gear power intervals
on flat terrain (or a trainer) and power hill intervals, as each type
stimulates slightly different adaptations in the body.
In the mid- to late base phase, complete one power-interval workout
each week. For example, warm up with 20 minutes of aerobic riding
then ride 10 x 20 seconds up a steep hill at maximum effort (out of
the saddle), spinning for 2 minutes after each climb and finally cooling
down with another 20 minutes of aerobic riding.
Start with a manageable number of intervals in the first week and
add intervals during each subsequent week (except recovery weeks)
for the next four to six weeks. You will then find your body ready
to handle and perform well in other, more challenging, types of high-intensity
workouts in the build phase.
Throughout the build and peak phases of training, go back to a smattering
of power intervals in an endurance ride once a week to maintain the
adaptations you earned in the late base phase. That’s all you
need to do to enjoy the triathlon-specific fitness benefits that you
can only get from churning out the largest wattage number you possibly
can.
