Threshold, or T-pace,
running is one of the most productive types of training that distance
runners can do. Training
at this pace helps runners avoid overtraining and yields more satisfying
workouts and better consistency.
The two types of threshold training that I
discuss in Daniels’ Running
Formula are tempo runs and
cruise intervals. Tempo runs—steady, moderately prolonged runs—have been
around for some time, but runners and coaches define them differently.
Cruise intervals are a series of repeated runs with a brief recovery between
runs. In my book, I address the differences and similarities between tempo
and cruise-interval workouts. Here, I’ll stick to tempo runs, including new
information on extended tempo runs.
Some runners and coaches use tempo runs for the
broader purpose of just going for a fairly prolonged, steady, solid
run—often, more for the psychological benefits (which can be considerable)
than the physiological. With threshold-intensity running, the physiological
benefit is to improve endurance: the ability to endure a greater and greater
intensity of effort for a longer and longer period of time. You might
perform some (longer) tempo runs at an intensity slightly below threshold
intensity, which offers a good opportunity to boost psychological endurance.
Longer tempo runs that begin in the less intense area of the zone and
progress to the higher end of the zone are accomplishing both the benefits
of a longer tempo run and the benefits of true T-pace running.
Establishing Your Threshold Pace
The proper pace for T-pace running is about 83
to 88 percent of VO2 Max,
or 88 to 92 percent of vVO2 Max
or maximum heart rate.
You can establish your proper pace for
threshold running fairly closely by running at a velocity that produces
an elevated yet steady state of blood lactate accumulation. This pace is
a little faster than a pace that you could maintain for two or more
hours (marathon pace for most people) but slower than the pace you could
maintain for 30 minutes (10K race pace for better runners). This pace is
easy to discern because at the latter pace blood lactate continues to
rise over the course of the run (that is, there’s not a steady state of
blood lactate accumulation). Also, at the former pace, blood lactate
slowly drops after an initial rise or after any elevated lactate
resulting from race surges (also not a steady state of blood lactate
accumulation).
Most runners can figure that their threshold
pace is equal to a pace they could race at for 50 to 60 minutes. In
fact, for slower runners, threshold pace might actually be 10K race pace
because they are taking nearly an hour to "race" this distance.
Intensity of effort, not necessarily distance of running or racing, is
what determines the degree of stress being put on the body’s systems.
Remember that the purpose of the workout is
to stress lactate-clearance capability, not to overstress that
capability. I refer to threshold training as "comfortably hard" running.
It shouldn’t feel "hard," which is the pace of pure interval training
