In December last year I posted here a review of some of the research about a way of training that scientists call “polarized.” That’s just a catchy way of saying do workouts with an intensity that is either high or low while avoiding moderate efforts. So train mostly at opposite ends of the intensity spectrum. There is another, more recent study, the best one done so far, which adds greater credibility to this concept. Before getting into that, however, let’s review what high, low and moderate intensities mean.
Polarized training studies always define “high” as any intensity above the anaerobic threshold (AnT). This is similar to the lactate threshold with which you may be familiar. On a perceived exertion scale of 1 (low) to 10 (high), anaerobic or lactate threshold is about a 7. If you use my heart rate zone system, that’s the start of zone 5a. When using a power meter with Coggan’s method, anaerobic threshold might be defined as occurring at about your Functional Threshold Power (FTP). If you’re familiar with the concept of FTP you then understand that an AnT effort could be maintained for about an hour.
“Low” intensity in polarized training is below your aerobic threshold (AeT). This level of intensity is best determined in a lab during an anaerobic or lactate threshold test. It’s the intensity at which breathing and muscular effort increase only slightly but noticeably above resting levels. If you know your lactate threshold heart rate, AeT is roughly 30bpm lower. You could maintain this effort for several hours. AeT is roughly the intensity used by age group athletes in very long events such as an Ironman triathlon or an ultraendurance running or cycling race. In other words, low intensity are efforts easier than AeT. They are very easy—what you should normally use during a recovery workout.
As you might have reckoned by now, the “moderate” intensity in polarized training is the training done between AeT and AnT. So with my heart rate zone system this is zones 2, 3 and 4. With Coggan’s power zone system that’s everything from zone 2 up to FTP.
Back to the most recent study on the topic of polarized training…
The study mentioned above is a good one to examine as it had a relatively large number of subjects (48) who altogether participated in four sports—running, cycling, triathlon and Nordic skiing. It’s also a good one because the subjects trained for a relatively long time—9 weeks. But as with all studies, the key to its applicability to you is knowing who the subjects were. They were all experienced athletes with an average aerobic capacity (VO2max) of 62.6. That’s generally not “world class,” but perhaps “national class.” It’s high and certainly at the upper end for most age group athletes. Their average age of the study's subjects was 31 and average weight was 162 pounds (73.8kg) with an average height of 71 inches (180cm). They had previously trained at least six times a week in their sports for a minimum of 10 hours per week and had competed for at least 8 years. I’m giving you all of these details because if you aren’t roughly of a similar background then the results of this study may not apply to you.
The 48 athletes were divided into four groups based on the training protocol they would each follow for the next 9 weeks.
HVT Group. This group trained with high volume meaning that the emphasis was on total hours of training weekly with nearly all of it in the low intensity zone (below AeT). But each week they did one session of an hour with intervals at about AnT (such as 5 x 7 minutes with 2-minute recoveries and 3 x 15 minutes with 3-minute recoveries). Every third week they included seven days of recovery with alternating low-intensity endurance sessions and days off. This training protocol is similar to what most of us do in our early Base periods.
THR Group. The focus of this group was training at AnT. They also trained in three-week blocks with two weeks of high volume including four interval sessions at AnT (such as 5 x 6 minutes, 6 x 7 minutes and 6 x 8 minutes each with 2-minute recoveries) followed by a recovery week. In the two hard weeks of each block they also did a weekly AnT session with longer intervals (3 x 15 minutes and 3 x 20 minutes with 3-minute recoveries). This way of training is similar to what many athletes do in their late Base or Build periods.
HIIT Group. This group placed an emphasis on training above their AnT but also followed a three-week periodization pattern. During 16 days in each three-week block they did 12 interval sessions above AnT (such as 4 x 4 minutes with 3-minute recoveries) with a day off every fourth day. Their recovery weeks were done at low intensity alternating with days off. This type training is what a few athletes do in their Build periods, although it certainly involved more interval sessions than most would do.
POL Group. This is the polarized group. They trained with a combination of the HVT and HIIT groups—either very hard of very easy. Also training in three-week blocks, they did two weeks with two HIIT interval sessions each week and with four long sessions done below AeT. Every third week (recovery week) they alternated days off with a single HIIT session and long workouts done below AeT. Their training was unique in that they never did any training between AeT and AnT. Few, if any, athletes train this way.
So what did the researchers find out when they tested the athletes after the 9 weeks of training and compared the results with their pre-tests? The group of subjects who showed the greatest physiological and performance benefits were in the POL group. Their VO2max increased, on average, 11.7%. Their time to exhaustion on a ramp test increased 17.4%. Peak velocity (running or skiing) and peak power (cycling) improved 5.1%. Velocity and power at AnT improved 8.1% even though they never trained at AnT. All of these were significant, positive changes. The HIIT group improved the last metric by 5.6%, time to exhaustion by 8.8%, peak velocity/power by 4.4% and VO2max by 4.8%. The THR athletes slightly improved their work economies (how much energy they used) at AnT but otherwise had no significant changes in physiology or performance. The HVT group experienced no significant improvements, which might be expected from a group of serious, high-performance athletes who normally train with frequent high-intensity sessions. This last group was, essentially, undertraining.
Again, the subjects in this study may be the key to determining if you should train with a polarized method. Even though HVT (the high volume, low intensity group) had no improvement, a novice (year 1 in their sport) or intermediate (years 2 and 3) athlete may find just the opposite—great improvement in physiology and performance by training with high volume and low intensity. In fact, training as the POL or, especially, the HIIT groups did may soon result in injury or overtraining. These methods are best used by advanced athletes (greater than 3 years in the sport). The more experienced the better.
Intermediate and the less experienced of the advanced athletes may make great gains by training with the THR group’s method—lots of time at about AnT. This way is somewhat similar to what Coggan proposes with his “sweetspot” training methodology with 2 x 20-minute intervals at 88-93% of FTP with 5-minute recoveries. I’ve seen a lot of athletes improve by training that way.
Of course, all of this raises the issue of periodization. It’s not a good idea to train the same way, week after week for an entire season. Not only does the risk of burnout increase, but there is likely to be a plateauing of gains in a matter of a few weeks which can’t be overcome by continuing with the same training method. Change is beneficial in these regards.
The underlying philosophy of periodization that I continue to drive home here is that workouts should become increasingly like the event for which you are training over time. This includes both intensity and duration. For stage racers it also includes the frequency of hard workouts. The general periodization model I use has the Build period (“specific preparation”—the last 12 weeks or so before an A-priority race) increasingly mimicking the stress expected in the race. So you have to decide how long the race will be and what the expected intensities will be and then design workouts that gradually produce some racelike combination of those stressors.
But in the Base period (“general preparation”—the weeks prior to Build) the workouts are not necessarily like the race. So this is the time, for example, to emphasize strength training in the weight room. This is “general” training since you never have to lift weights during an endurance event such as a bike race or triathlon. In the same way, if your event calls for racing in the “moderate” intensity range (between AeT and AnT) then doing the HIIT-type of intervals in the late Base period may be a good idea as it is likely to boost your fitness significantly. This could lift your Build period, race-specific training to a higher level. So for a long-course triathlete or marathon runner the time for polarized training may well be in the late Base period—the last few weeks before starting the Build period.
On the other hand, road cyclists may find that the best time for polarized workouts is in the Build period since the outcomes of these types of races are usually determined by brief, intense efforts done well above AnT. So a cyclist doing road races or criteriums may well do lots of very high intensity intervals and sprints along with climbs above AnT in the last few weeks prior to an A-priority race.
The bottom line here is that even though polarized training has repeatedly been shown to produce the greatest improvements, how you train throughout the year must be seen in a far broader perspective. Smart training is not an either-or proposition. You don’t just train one way or the other throughout the entire season. It always comes down to taking a long-term view relative to your races, goals and personal limiters and then designing a training program that addresses these matters. In other words, smart training is generally a rather complex and laborious task. This is not to say that it can’t mastered by amateur athletes. I come across many such people all the time. But if you aren’t interested in becoming a student of sport science then you may be better off hiring a coach or perhaps finding a generic training plan that guides you through your race preparation.