As a runner, the threshold you should be most concerned about
is your lactate threshold—the point at which, during exercise
of increasing intensity, your blood-lactate level rises.
When its energy demands are being met aerobically (your
breathing in oxygen), your body produces little lactate. But
as workout intensity increases and oxygen becomes more scarce,
something called anaerobic glycolysis kicks in. This produces
energy and lactic acid. When your lactic-acid level exceeds
your body's ability to deal with it, you're in trouble: Blood
lactate dramatically increases, energy production and muscle
contraction decreases, fatigue ensues, and performance drops.
Naturally the faster you can run without crossing your
lactate threshold, the better off you'll be. An article in last
January's Journal of Medical Science for Sport and Exercise
showed that speed at lactate threshold is the best physiological
predictor of distance-running performance. Indeed, Frank Shorter
was said to have had a marginal max VO2 but was able
to run at a high percentage of max VO2 before reaching
his lactate threshold.
Untrained individuals may reach their lactate threshold at 50
to 60 percent of max VO2, elite endurance runners
at 70 to 90 percent. By training just below this zone, you can
inch your threshold upward, allowing you to race faster.
First you need to find your threshold. To do so, you
can ask someone to draw blood from your ear while you max out
on a treadmill. Or, if that's somewhat inconvenient, here are
two easy ways to make a reasonably close guess:
Then you need to train to raise your threshold. Try
the following two kinds of workouts, both run at the same pace.
Begin with a 1- to 2-mile warmup and strides, and wrap up with
a 1- to 2-mile cooldown.
Tempo
Runs
It's no accident that most hard workouts performed by
Kenyan runners are variations on the tempo run. Take a hint
from them, and build a weekly tempo run into your schedule.
Run at a steady lactate threshold pace for at least 20 minutes.
Over a period of 4 to 6 weeks, extend this 20-minute run to
4 and then 5 miles. Run on a flat road where you can check your
mile splits to keep your pace steady. If you can't maintain
an even pace through the end of the run, you're going too fast.
This will be a hard run, but not a race. Remember, you're working
at the edge of your threshold—not beyond it.
Mexican
Tempo Intervals
No, it's not a new combo at Taco Bell. Rodolfo Gomez
of Mexico—who has coached such runners as German Silva and Adriana
Fernandez, both New York City Marathon winners, and who himself
finished second at New York in 1982—has earned much success
with this workout.
These 1000-meter repeats are run at lactate-threshold
pace but with only 60 seconds of recovery between them. That's
enough time to stop, shake your legs out, take a few deep breaths,
and begin again. These mini-breaks provide a mental break but
are short enough to keep blood lactate at close to threshold
level.
Gomez's athletes would run 15 of these, but a more realistic
goal would be to start with six and work up to 10. The key to
this workout is to keep the recovery short and the pace consistent.
If you're begging for more recovery or your times are slowing
after a few repeats, you started off too fast.
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