Interval Training
Author: Richard Weil, MEd, CDE
Medical Editor: William C. Shiel Jr., MD, FACP, FACR
Are you pressed for time? Are you interested in improving your aerobic
capacity and exercise performance in less than one-fifth the time of traditional
endurance training? If so, then interval training is just what the exercise
physiologist ordered. Indeed, research proves that you can improve your
endurance and recovery from intense bouts of exercise with just one hour per week
of interval training compared with five hours per week of traditional endurance
training! Athletes know the magic of intervals; they use them all the time to
improve their performance, and they know that intervals help speed up recovery
so they can get going quickly after a blast of energy (like a sprint). In this
article, I'll review what interval training is, describe the benefits and the
studies that prove it works, and then show you how to design an interval-training program.
What is interval training?
Interval training is a method of training where
you increase and decrease the intensity of your workout between aerobic and
anaerobic training. Interval training in Sweden, where some say it originated,
is known as fartlek training (Swedish for "speed play"). The protocol for
interval training is to push your body past the aerobic threshold for a few
moments and then return to your aerobic conditioning level with the objective of
improving your performance (speed, strength, and endurance). The aerobic
threshold is the intensity where your body switches from burning a greater
percentage of fat to a greater percentage of carbohydrate and is generally 85%
of your maximum heart rate (train below 85% and it's aerobic; train above 85% and
it's anaerobic).
How are interval-training sessions designed?
The idea is to set up work to
active-recovery ratios (work:active-recovery) in intervals of minutes. For
instance, let's say you usually train comfortably at 6 mph on the treadmill.
So, after your warm up and a few minutes at 6 mph, you sprint for one minute at
7.5 mph and then jog again at 6 mph for three minutes (1:3 ratio: a total of
four
minutes). You continue these intervals for your entire workout and then cool
down for about five minutes.
How do I determine how hard to work?
Heart rate is a good indicator of how
hard you're working, and it's easy to measure, so it's an ideal method for setting up
and monitoring intervals. Here's an example. Say your heart rate is 70% of your
predicted maximum when you jog at 6 mph. After you warm up and spend a few
minutes at that pace, you increase the speed for your work interval to 7 mph,
which might be 85% or even 90% of heart rate max, and then you cut back on the
speed to 6 mph at a heart rate of 70% of max for your active-recovery. Below is
a sample 28-minute interval workout (excluding warm-up and cooldown). Keep in
mind that you can spend the entire workout doing them or vary it and do just
some of the work intervals, and note that the time of each interval in this
example always adds up to four minutes.
Warm-up: five minutes at 5-6 mph
Interval 1:
three minutes at 6 mph (70% of max heart rate)
Interval 2: one minute at 7 mph (80% of
max heart rate)
Interval 3: three minutes at 6 mph
Interval 4: one minute at 7 mph
Interval 5: three minutes at 6 mph
Interval 6 - harder: one minute at 7.5 mph (85% of max
heart rate)
Interval 7: three minutes at 6 mph
Interval 8: one minute at 7.5 mph
Interval 9: three minutes at 6 mph
Interval 10: one minute 7.5 mph
Interval 11: three
minutes at 6 mph
Interval 12: one minute 7.5 mph
Interval 13: three minutes at 6 mph
Interval 14: last push -- one minute at 8 mph (90% of heart rate max)
Cooldown: five
minutes at 5-6 mph, then walk
Some athletes train as high as 100% of heart rate maximum. I don't recommend
that beginners go above 85%-90%. 1:3 work:active-recovery ratios are the
standard starting point.
Next: How often should I increase the intensity of the intervals? »
Exercise & Fitness RSS