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.
What Kind of Intervals Should I Do?
How you manipulate these three portions of the workout is based on the distance you race. The accompanying table offers one example of a simple interval workout for each sport for the common triathlon race distances. There are many other ways of organizing these workouts. These are just common examples. Each of these interval sessions may be done once a week for each sport during the build period of your season.
Interval Components Based on Race Distance and Sport
| Race Distance – Sport | Work Interval Duration* | Recovery Interval Duration* | Work Interval Intensity** | Recovery Interval Intensity | # of Work Intervals (reps)*** | Example WI (RI) **** |
| Sprint – Swim | 100 y/m | 10-20 sec | T-5 | Stand at wall | 4-7 | 5×100 @ T-5 (15 sec) |
| Sprint – Bike | 3 min | 3 min | CP6 or RPE9 | RPE1 or Easy spin | 3-6 | 5×3 min @ CP6 (3 min) |
| Sprint – Run | 3 min | 3 min | CP6 or RPE9 | RPE1 or Easy jog/walk | 2-5 | 4×3 min @ CP6 (3 min) |
| Olympic – Swim | 200y/m | 10-20 sec | T+5 | Stand at wall | 4-7 | 5×200 @ T+5 (15 sec) |
| Olympic – Bike | 8 min | 2 min | HR4-5a or CP30 or RPE7-8 | HR1 or RPE1 or Easy spin | 3-6 | 4×8 min RPE7-8 (2 min) |
| Olympic – Run | 6 min | 90 sec | HR4-5a or CP30 or RPE7-8 | HR1 or RPE1 or Easy jog | 3-6 | 4×6 min RPE7-8 (90 sec) |
| Half-Iron – Swim | 300 y/m | Easy 25 swim | T+10 | Easy 25 swim | 4-7 | 5×300 @ T+10 sec (25 easy) |
| Half Iron – Bike | 20 min | 5 min | High HR3 or CP90 or RPE5-6 | HR1 or RPE1 or Easy spin | 2-5 | 3×20 min @ CP90 (5 min) |
| Half Iron – Run | 12 min | 3 min | High HR3 or CP90 or RPE5-6 | HR1 or RPE1 or Easy jog | 3-6 | 3×12 min @ CP90 (3 min) |
| Ironman – Swim | 500 y/m | Easy 25 swim | T+15 | Easy 25 swim | 4-7 | 5×500 @ T+15 sec (25 easy) |
| Ironman – Bike | 30 min | 8 min | Low HR3 or CP90 or RPE 5-6 | HR1 or RPE1 or Easy spin | 2-5 | 3×30 min @ HR3 (8 min spin) |
| Ironman – Run | 20 min | 5 min | Low HR3 or CP90 or RPE5-6 | HR1 or RPE1 or Easy jog | 2-5 | 3×20 min HR3 (5 min jog) |
* y/m = yards or meters. ”min” = minutes. “sec” = seconds.
** Heart rate (HR) zones based on the system in The Triathlete’s Training Bible. Note that HR is not a good way to gauge intensity of short intervals. T-5 refers to your swim T-time (average-100 pace for 1000-time trial) minus 5 seconds per 100. T+5 is T-time plus 5 seconds. CP means “critical power” (bike) or “critical pace” (run) – the highest average power or pace you can sustain for 6 minutes (CP6), 30 minutes (CP30), or 90 minutes (CP90). RPE is “rating of perceived exertion” and is gauged on a 1- (easiest) to-10 (hardest) scale.
***Start at the lowest number and increase by one work interval weekly over 4-5 weeks. Then maintain the highest level for an additional 3-4 weeks.
****Venues for these workouts are pool for swimming, road or indoor trainer for cycling, track or other soft surface for running. For variety add uphill work intervals or rolling courses for bike and run.
