Owen Anderson, running research news, intervals v. tempo running…

Posted on February 28, 2007 by

owen anderson, running research news, intervals v. tempo running…

Which will have a bigger impact on your performances?

Dear Running Friend,
As you plan your workouts, you probably wonder from time to time about
whether tempo sessions or interval workouts have a larger effect on your overall
fitness. Tempo sessions have been a mainstay of running training for over 40
years, and they are thought to have a positive influence on lactate-threshold
running speed, a key predictor of performance. Interval training has been
around for even longer, and many experts link interval work with upgrades in
speed, running economy, and aerobic capacity, which are all decent indicators
of performance potential.
To examine the relative value of interval and tempo training, Peter Snell
(pictured at right, in his younger days, running on a beach in New Zealand) and
his colleagues at the University of Texas Southwestern Human Performance
Center asked some well-conditioned runners to focus on either tempo running or
interval training for a period of 10 weeks (1). If the name Peter Snell rings
a bell, the researcher from Texas Southwestern is the same Peter Snell who
won a total of three gold medals at the 1960 and 1964 Olympics and also
captured two gold medallions at the Commonwealth Games in 1962. Snell’s
world-record performance of 1.44.3 for 800 meters, accomplished in February, 1962,
remains the New-Zealand national record to this day. After his running career
ended, Snell earned a Ph. D. in exercise physiology and has been a researcher
at Texas Southwestern since 1981.
In Peter’s research, one group of runners carried out tempo runs twice a
week (the rest of their running was moderate-paced effort). These tempo
workouts involved running for 29 minutes at a running speed which roughly
corresponded with lactate-threshold velocity – the pace above which blood-lactate
levels begin to increase dramatically. The average intensity during these
sessions was about 70 to 80 percent of maximal aerobic capacity (VO2max).
Runners in a second group carried out no tempo running at all but instead
conducted two interval sessions per week. During these interval workouts, the
runners cavorted through 200-meter intervals in 33 to 38 seconds and
performed 400-meter intervals in 75 to 80 seconds, completing a total of about three
miles of interval running per workout. Exercise intensity during this
interval running averaged 90 to 100 percent of VO2max.
After 10 weeks, the runners from both groups ran 800-meter and 10-K races.
In these competitions, the interval-trained runners fared far better than the
tempo-tutored harriers. For example, the interval-based runners improved
800-meter time by an average of 11.2 seconds and bettered previous 10-K times
by 2.1 minutes.
Meanwhile, the tempo-training devotees shaved just 6.6 seconds from their
800-meter times and upgraded 10-K running by only 1.1 minute, roughly half the
improvement achieved by the interval-trained competitors. VO2max soared by
12 percent for the interval runners but nudged upward by only 4 percent for
the tempo-trained runners.
These results were observed even though the tempo-trained individuals
engaged in a far-greater amount of quality work over the 10-week period.
Specifically, the tempo runners completed 58 minutes per week of tempo training, while
the interval individuals spent just 31 minutes per week conducting fast
interval effort. This led to a 270-minute edge in quality training for the tempo
group over the 10-week period.
Despite this apparent disadvantage, the interval-trained runners gained
considerably more physiological and competitive fitness. A key lesson to be
learned here is that intensity is always the most-potent producer of fitness; it
is a much-stronger stimulus for improvement than training volume and workout
frequency. When you conduct your intervals at 90 to 100 percent of VO2max
(and at higher intensities, too), the amount of fitness gained per minute will
always be greater, compared with the running capacity accrued at lower
intensities. As you can see from Snell’s research, each minute of high-quality
work can sometimes produce twice as much gain in fitness as double the amount
of lower-quality exertion.
Incidentally, recent research has discredited tempo training as a powerful
booster of lactate-threshold speed, the adaptation with which it has been
traditionally linked. The problem is that tempo training, carried out at close
to lactate-threshold velocity, by definition produces very little increase in
blood-lactate concentrations and thus does a poor job of stimulating muscle
cells to get better at clearing lactate from the blood. Blood-lactate removal
by the muscles is a key component of improving lactate-threshold speed.
Note, too, that interval training is superior to tempo running when it comes
to matching training paces with goal race speeds (unless you are planning to
run only 15Ks and half-marathons). This is obviously a good thing from the
standpoints of enhancing goal-speed running economy and mental confidence.
As Snell pointed out in a telephone interview with _Running Research News_
(http://www.runningresearchnews.com/) , “Perhaps the best way to train is to
spend the maximum-possible amount of time running at a pace which is closely
related to the demands (or pace) of the race you’re shooting for, without
getting overtrained.”
So what kinds of intervals would work well for you? 1600s at 5-K pace, 800s
at four seconds per 400 meters faster than 5-K pace, and 400s at eight
seconds per 400 meters faster than 5-K speed would all be very productive. During
such interval sessions, each jog recovery can last about as long as the
duration of the preceding work interval. Especially for the 1600-meter
intervals, it is smart to pare down the time-lengths of these recoveries over time, as
you get fitter.