Interval training works. Bicycle racers have been doing interval training for decades, and hard training benefits long distance riders, too. Penseyres did a lot of interval training in 1986, when he set the solo RAAM speed record and again in ’95 when he set the RAAM 50+ Team record.

by Pete Penseyres

Pete Penseyres won the Race Across America twice (1984 and 1986), holds the RAAM men’s average speed record of 15.40 mph (1986), with Lon Haldeman holds the tandem transcontinental record (1987, 7d 14h 55m), was a member of Team Lightning that won HPV RAAM (1989, 5d 1h 8m), was a member of Team Bicycling which set the 50+ RAAM record (1996, 5d 11h 21m) and is a national champion road racer.


Training for bicycle racing and ultra riding is divided into four phases: Base Building, Intensity Training, Peaking, and Tapering. (For an overview of the phases, see Training for 12-hour and 24-hour Races. This article describes a specific interval training program for the Intensity phase, which can be used by riders training for events ranging from fast centuries and double centuries to RAAM qualifying races and the Race Across AMerica. .

How Long? How Many? How Hard?

You should spend 8 to 16 weeks (2 to 4 four week cycles) in the Intensity phase. Total volume should decrease from the Base phase and two interval sessions are included each week. To maintain endurance, one long ride per week is also included and should be done in Heart Rate Training Zones 1, 2 & 3. The long ride length depends on your target event. Solo RAAM riders should be approaching 24 hours, while team RAAM riders can top out at 6 to 8 hours. Those are probably the two extremes for ultra riders, so everyone else should be somewhere in between.

There should be one session of hill intervals and another of flat intervals. As in the other phases, the total time spent doing the intervals increases each week during a four week cycle, then is reduced to just above the first week’s total and builds higher in the following four week period. As a ballpark figure, plan about an hour or less for interval sessions in Heart Rate Zones 4 and 5. It is important to schedule enough recovery after each of these sessions, since that is when your body will actually adapt and make you faster. You should also schedule an easy day before each of the interval sessions (so you can go hard enough to make these sessions effective). Since the long ride should not be the day before or after one of these interval sessions, your weekly schedules will likely include the long ride on one of the weekend days and intervals Tuesday and Thursday. The other days can be recovery rides of relatively short duration and be almost exclusively within Zone 1.

Pinpoint Your Anaerobic Threshold (AT) Heart Rate

My program for the 1996 BICYCLING Team RAAM was provided by Tom Ehrhard and included four different types of intervals. Tom stressed the importance of knowing your AT as closely as possible (within a few beats per minute) because two types of the intervals are done just a few beats above or below AT. You can determining your AT by doing a 30 to 60 minute time trial. I can maintain a heart rate slightly above AT for an hour, if I am well rested. Another method is to use an indoor trainer at a constant load for about 15 minutes. You want a load that will cause your heart rate to almost level off for the last few minutes. Too little load will cause your heart rate to level off early and/or completely. Too much load and your heart rate will continue to rise or you may not even be able to complete the effort. I had good success with this method using a CompuTrainer in the stand-alone mode by setting the load at a constant power level and using a commercial grade fan to stay cool (excessive heat build up will cause a continuing heart rate increase). I had to do this a number of times at different power levels to find the correct load, but my AT determination was quite accurate. If, after doing your best to determine your AT heart rate, you are still in doubt, it is better to guess low than high for the purpose of doing intervals.

Details, Details…

The four types of intervals Tom specified in my team RAAM program were:

1. Base intervals

Done 5 to 10 bpm below AT for about 10 to 30 minutes with 10 minutes or so recovery between each. These intervals are not done in the intensity phase, but help you get ready for the others.

2. AT Stimulation

Done 1 to 5 bpm below AT for about 10 minutes with a similar recovery time between each. These are harder to do indoors than the more intense (but shorter) intervals. I have a convenient hill on a frontage road that takes 10 minutes to climb at my AT. When I do these as hill intervals, I go to the top, spin down, roll around until 10 minutes has passed and then start again. When I do these as flat intervals, I almost always do them on the only five mile flat stretch of road near home with no stop signs or lights. I do them in one direction and recover by riding easily back to the start (which takes about 12 to 14 minutes). I do these in sets of five or less and, if more than one set, take at least a 20 minute break between sets in Zones 1 and 2. Start your watch for the interval when you start the hard effort. It usually takes my heart rate almost half the interval time to reach the target heart rate range, if I go at a constant effort.

3. Lactate Buffering

Done 1 to 3 bpm above AT for about five minutes with a shorter or harder (incomplete) recovery phase. I do the hill intervals of this type on part of the same hill I use for the AT intervals. After I finish each interval, I spin down the hill to the same point and immediately start again. It takes only two minutes to get back down and complete both U-turns. I take more than one look before starting these turns to make sure there is no approaching traffic. These intervals are pretty intense and I don’t want to trust one quick look when I’m anaerobic. (I also do this anytime I make a U-turn on any road, which I recommend everyone add to their road survival skill routines.) I do these in sets of no more than five and take at least 10 minutes recovery between sets. When I do these as flat intervals, I either use the CompuTrainer with the same two minute incomplete recovery between intervals or on the road. Again, I use the same section of road and return to the start each time. In this case, it takes about six minutes to return, so I ride hard enough to keep my heart rate within 10 bpm of AT to prevent complete recovery. As above, if I go at a constant effort, it takes about one-half of each interval to get into the target zone and, if I do them well, my heart rate at the end of each interval of a set is as high or slightly higher than the preceding interval.

4. VO2 Max

Done at an effort about half-way between AT and all-out for 2 to 4 minutes with recovery at an easy effort for 4 to 2 minutes. Tom specified these to start with 2 minutes on and 3 off, progressing to 3 on / 3 off, and finally to 4 on / 3 off or 3 on / 2 off. As hill intervals, I do these on the same hill and spin easily down after each one. As flat intervals, I always do these on the CompuTrainer, because they are so hard that I don’t trust myself to do them on the road. My hill is a much wider road, with a good shoulder and almost no traffic, so if I’m very careful on the U-turns, they are reasonably safe. Heart rate is not used to gauge effort for these intervals. If I do these intervals at the right effort, I can barely finish the last one in each set. My heart rate is whatever it takes to achieve this goal. These intervals are so difficult that they should not be done until the AT Stimulation and Lactate Buffering intervals have been mastered (at least one 4 week cycle).


A couple of years ago, my brother asked me to set up an interval program to prepare him for the Master’s Nationals, but he didn’t decide to go until less than two months earlier and had not done any interval training. I worked backwards from the date of the Nationals using the program Tom specified for me and had him doing VO2 Max intervals the first week. His comments were (1) “Are you trying to kill me?” and (2) “I’m telling Mom!”.

I learned how important it is to follow the guidelines of progression and not try to do too much, too soon. In retrospect, that should have been obvious, but, as I tried to explain to Jim and Mom, it was an innocent mistake!


I was tested by Randy Ice in his lab on a Monarch Ergometer in October, 1995, after a full season of USCF road racing and a PAC Tour, just before starting to use Tom’s program. I was tested again in July, 1996, just before RAAM and part way into the tapering phase.

The results presented below show two beneficial results (1) a 35 watt increase in power output at any heart rate and (2) another 35 watt increase at AT.

Oct ’95
Heart Rate
July ’96
Heart Rate
210 watts 139 bpm 128 bpm
228 146 133
245 150 138
263 159 (AT*) 143
280 162 151
298 168 157
315 172 163
333 178 168 (AT*)
350 180 171
368 185 178
385 180
403 185

(AT*) designates heart rate at AT

For ultra riders, the most important benefit of this training program is economy. You will go faster while producing more power at the same heart rate. Your cruising speed (at the same perceived effort) will increase. In addition, you will have more of a buffer zone to the disaster that takes place when you ride above AT during an ultra event. This applies to solo RAAM, team RAAM, and everyone in between.

The big question is whether or not you need to do all four types of intervals to achieve these benefits? No one doing ultra events rides above AT if they are pacing themselves to do their best. Could you skip the Lactate and/or VO2 Max intervals? That would be nice, because they are very hard.

You can enter, and often finish, ultra events without going through this kind of training, but it is a pay me now or pay me later situation. You can train in your comfort zone and suffer through the event you’ve set as your season goal. Or, you can suffer during the training and actually enjoy your target event, with the mental edge of knowing you’ve paid your dues. Since the mental aspect of ultras is so important, you will also be much more likely to get through the tough periods and avoid the dreaded DNF.

Choose wisely!