by Joe Friel (from the Training Peaks Blog)
How would you like to improve your race performance by three percent in four weeks? Three percent isn’t much, you say? Well, that would mean going from a 2:30 Olympic-distance finish time to a 2:25. For an Ironman three percent off of a 12-hour time would put you at the finish line 21 minutes sooner. Intervals are the key to such gains — if you do the workouts correctly.
And three percent is conservative based on research that has looked at the benefits of interval training. Some studies put the performance benefits as high as six percent, so you might be able to double those time gains described above. Most studies found the benefits occurred with only one interval session per week. That’s four workouts in a month to become at least three-percent faster. Most triathletes would improve their race times significantly by doing one interval workout in each sport weekly during the build period of their seasons. The build period starts about 12 weeks before your first A-priority race of the season and ends two or three weeks before.
But I Already Do Intervals
Most triathletes tell me they do intervals. I’ve found few self-coached athletes, however, who know what the various types of intervals are, how to choose the right one for their needs and how to blend them into a comprehensive training program.
Unfortunately, most triathletes do a workout I call “intervals ‘til you puke.” These are intervals done as fast as possible with no thought as to what the pace or power should be, how long the fast portions should be, or how much recovery should be taken between the fast portions.
Then there are athletes who don’t do intervals at all. They dislike the agony and are more likely to swim, bike and run at moderately hard efforts a lot. This is 3-zone training and has little benefit once you leave the base period of your season—unless you are training for half ironman- or ironman-distance races that are raced at moderate effort. But for the shorter distances 3-zone workouts are not hard enough to produce the physiological benefits necessary to race faster, but are hard enough to leave you feeling tired and in need of some down time to recover. The worst of both worlds.
What Are Intervals?
So what are intervals all about? Let’s get the language of intervals straightened out first. The word “interval” actually refers to the rest time between the hard portions. But since nearly everyone uses the word “interval” to mean the hard portions it probably would help to eliminate confusion if we call those hard portions the “work intervals” and the easy portions the “recovery intervals.”
The three most critical components of an interval workout are:
- intensities of the work and recovery intervals
- durations of the work and recovery intervals and the total time spent
- work interval intensity within the workout
By changing each of these parts the benefits of the workout are changed. The most common mistakes made by self-coached athletes are to make the work intensity too great and the recovery interval too long.