Track Coach

Running Periodization Part 3: Block and Undulating Periodization

By Jason R. Karp, PHD, MBA

Adapted from the book Running Periodization: Training Theories to Run Faster, by
Dr. Karp.
This is the third article in this series.

“The concentrated training of limited abilities separately is more effective than the training of varied athletic abilities simultaneously.”

In addition to linear and reverse linear periodization, the subjects of the first two parts of this series, there are a couple of other ways to plan your athletes’ training. 

Block Periodization

Multi-targeted training doesn’t provide a sufficient stimulus for long-term improvement. Concentrated training cannot be managed for multiple targets at the same time. Your athletes may get great results initially, but they can also plateau quickly. With multi-targeted training, you’re asking them to respond and adapt to multiple stimuli at the same time. Their bodies are pretty smart and could probably handle the job given enough time to do so, but there will almost certainly be a trade-off, since different types of training—like aerobic and anaerobic training—provoke different responses and adaptations, some of which can be incompatible. 

A clever way to avoid incompatible adaptations is with another model of periodization—block periodization, which includes sequencing of specialized mesocycles, called blocks, that concentrate on only a single or a couple of compatible abilities at a time using a large volume of workouts, and train multiple fitness factors consecutively rather than concurrently. Since physiological and biochemical changes require periods of at least two to six weeks—the typical duration of mesocycles—blocks are organized as mesocycles. Block periodization consists of three types of specialized mesocycle blocks: (1) accumulation, which develops basic abilities, such as technique, aerobic capacity, and muscular endurance (with an emphasis on mitochondrial biogenesis and metabolic capacity of slow-twitch muscle fibers); (2) transmutation, which uses shorter mesocycle blocks that include high-intensity workouts to develop race-specific abilities, such as anaerobic endurance and more specialized technical skills; and (3) realization, which develops speed, race-specific tactics, and recovery (taper) prior to the race., Thus, accumulation is analogous to the general preparation phase of the traditional linear periodization model, transmutation is analogous to the specific preparation phase, and realization is analogous to the competition phase. 

The major principle of block periodization is that the concentrated attention on and training of single targets or abilities separately is more effective than the training of several fitness factors or athletic abilities simultaneously. While variation is a critical component of periodized training, periodically reducing that variation to concentrate on a specific target can induce rapid development of that target. Low-intensity and high-intensity training are carried out in specific blocks to promote beneficial training adaptations, with high-intensity training succeeding low-intensity training.

Block periodization may be more effective than traditional linear periodization for highly trained and elite runners, since developing multiple abilities at once is challenging in this population, primarily because very fast runners are closer to their genetic potential, and the accumulated fatigue from the volume and intensity of training needed to squeeze out even more improvement would likely exceed the capacity to recover from the training stress. Recreational runners and lower-level runners (like high school freshmen and sophomores), on the other hand, who are far away from their genetic capabilities, can often benefit from training multiple fitness factors simultaneously.  

The main problem with block periodization is that the training of only one fitness factor at a time increases the risk of detraining other factors that are not being stimulated during the specific block. To avoid that from happening, it’s important to use maintenance workouts that provide a sufficient stimulus to prevent previous adaptations from being lost. Since some fitness factors decline faster than others, the sequencing of blocks is also important to maximize the residual effects from previous training blocks. New runners lose fitness quickly when they stop training. If your athletes have been training for many years, they can hold on to their fitness longer. Experienced runners retain their “trainedness” for a longer amount of time, in part because the physiological adaptations they have made become a more permanent part of their biology.

Block periodization is more effective and time efficient than linear periodization, causing greater increases in VO2max, power output at VO2max, and power output at lactate threshold. That is the conclusion of several scientific studies that have compared the two types of training. In one of those studies, scientists at Lillehammer University College in Lillehammer, Norway divided 19 trained cyclists into two groups: (1) a block periodization group, which did a one-week block of five high-intensity workouts (6 x 5 minutes or 5 x 6 minutes at 88 to 100 percent max heart rate (zone 3) with 2½ to 3 minutes recovery between reps), followed by three weeks of one high-intensity workout per week plus a high volume of low-intensity training, and (2) a traditional periodization group, which did two high-intensity workouts per week for four weeks plus a high volume of low intensity training. Both groups did the same volume of interval training and low-intensity training over the entire four weeks. For two months prior to the study, neither group did any interval training. The cyclists in the block periodization group increased their VO2max by an average of 4.6 percent and their submaximal power output by 10 percent, while VO2max and power output did not change in the linear periodization group. 

In a similar study on 15 trained cyclists by the same group of researchers, the same training intervention was extended to 12 weeks, with the block periodization group repeating three times the four-week pattern of one week of five high-intensity workouts and three weeks of one high-intensity workout per week, while the linear periodization group did two high-intensity workouts per week for the entire 12 weeks. After 12 weeks, the block periodization group increased its VO2max and submaximal power output slightly more than did the linear periodization group. Both groups increased peak power output and the average power output during a 40-minute time trial, however, there was no difference in the amount of improvement between groups. 

While these and other similar studies are relatively short (11 days to 12 weeks) and did not use running as their training interventions, they do suggest a possible effective way to structure mesocycles—one week of low-volume/high-intensity training with several hard workouts, followed by three weeks of high-volume/low-intensity training with just one hard workout per week. In other words, go hard for one week with multiple workouts, then back off the intensity for three weeks, doing one maintenance workout each week. However, a word of caution is necessary here, because the greater relative anatomical stress of running (and thus its greater injury potential) compared to other endurance sports that have been the subject of research studies may necessitate more recovery between high-intensity workouts in a block periodization program for runners. 

One way to include more recovery is to use microcycles that are longer than one week and spread the intense workouts around that longer time frame. For example, your athletes can include three to five intense workouts in a 10-day (instead of 7-day) microcycle, as part of a 40-day (instead of 28-day) mesocycle block. If it’s too challenging to deviate from a 7-day calendar to plan the training this way, they can keep the 7-day duration for the three non-intense microcycles of the mesocycle block and extend only the intense microcycle block for more recovery during that training period.   

Block periodization. During the first microcycle of the first two mesocycles, the training load is increased with increased intensity. The next two microcycles decrease the intensity but increase the volume before backing off on both volume and intensity for a recovery microcycle. The third and fourth mesocycles are designed similarly to regular, non-block-periodized mesocycles.

Block periodization is not without criticism. For starters, it’s fairly obvious that using concentrated blocks of specialized, intense training will cause your athletes to get fitter in a hurry, especially when they have not been doing intense training. It has been known for a long time that when intense interval training is added to an endurance training program, fitness and performance improve. Also, compared to varied training, concentrated training causes a shorter-lasting fitness effect. That’s why it’s important to use maintenance workouts to maintain fitness and prevent detraining after the concentrated block.

Perhaps the best way to train with block periodization is to add a concentrated block mesocycle at the beginning of each macrocycle, when your athletes are just coming off a recovery microcycle and beginning a new phase of training. For the first one or two mesocycles that begin each of the three major macrocycles of the year—general preparation, specific preparation, and competition—concentrate their training on just one fitness factor. Plan several stimulating workouts that focus on that fitness factor during the first microcycle of those mesocycles. Then, spend the next few microcycles (weeks) backing off from that stress, using occasional maintenance workouts to maintain fitness. Since the congregated training stress of block periodization can cause a lot of fatigue, limit the duration of those mesocycles to three to four weeks.

The controlled nature of block periodization can make your athletes’ training better, because it narrows their focus. They become more productive, focusing on what will get them where they want to go and eliminating what won’t.

But running, like life, is not always blocked into neat, little, organized spaces, nor is it linear. Running must be fluid with life and the constant journey that feeds your athletes’ souls with desire and passion. Running, like life, has ups and downs that coalesce into a beautiful, undulating rhythm. 

And so there is one more model of periodization we need to talk about. 

Undulating Periodization

Many years ago, I was talking to a coach of a successful college cross country team, an Olympian himself, who had his athletes do one type of workout on Monday, another type of workout on Wednesday, and what the coach called a “wild-card” workout on Friday that the athletes could choose based on what they thought they needed to work on. The coach believed in training multiple aspects of fitness and all the metabolic energy systems all the time. Runners and other coaches often do the same, training multiple fitness factors simultaneously within a microcycle. 

A standard week of training for many runners is an interval workout on Tuesday, tempo run on Thursday, and long run on Saturday or Sunday, with a mix of aerobic runs and perhaps strength training on other days. 

Although the coach who prescribed this training to his athletes didn’t mention it during our conversation, there is a term for this type of training—undulating
, which includes drastic variations in volume and intensity either daily or weekly throughout the training program. It is based on the theory that if a training stimulus is repeatedly presented in the same way, its effect diminishes. So instead of repeating the same stimulus, you constantly change it—from week to week and even from day to day. 

Undulating periodization can serve as a way to maintain (or even increase) aerobic development during latter mesocycles of a macrocycle, which is often neglected in a linear periodization program, when the latter mesocycles focus on intensity. Since aerobic development is always important for a distance runner, undulating periodization injects volume throughout the training program.

As with most of the scientific research on periodization, undulating periodization has been studied most often as it pertains to muscular strength. Indeed, it was developed specifically for strength training. Studies that have compared undulating periodization to other periodization models have shown that undulating periodization is equally or slightly more effective as linear periodization to increase strength.,,, However, a review of 23 studies on strength training found that undulating periodization increases muscular strength, but is less effective than linear periodization.  

Due to the constant variation in volume and intensity, creating an undulating periodization program is considerably more work compared to designing other types of periodization programs. When the intensity is low, the volume is high, and vice versa. The intensity pattern doesn’t need to be repeated; it can vary throughout each week. For example, a four-week mesocycle early in a macrocycle (when the focus is on volume) can take the following pattern:

Week 1: easy / medium / easy / medium / easy / hard 

Week 2: medium / easy / medium / easy / medium / hard

Week 3: easy / hard / easy / medium / easy / medium

Week 4: medium / hard / easy / medium / easy / medium

A four-week mesocycle late in a macrocycle (when the focus is on intensity) can take the following pattern:

Week 1: hard / medium / easy / medium / hard / easy

Week 2: medium / easy / hard / easy / medium / hard

Week 3: easy / hard / medium / hard / medium / easy

Week 4: hard / easy / medium / hard / easy / hard

Any type of periodization training program is (or at least should be) undulating in nature, consisting of hard days, moderate days, easy days, and rest days, which causes undulating peaks and valleys within each microcycle. The unique characteristic of undulating periodization is that these peaks and valleys are of different stimuli. By contrast, linear, reverse linear, and block periodization are narrower in their focus, planning the training with more specific themes to each microcycle and mesocycle. 

I am more in favor of the linear, reverse linear, and block periodization approaches, which focus on one or two fitness factors at a time. That doesn’t mean that every day of a microcycle or mesocycle is the same, as the volume and intensity are manipulated to drive adaptation to a specific stimulus. Perhaps undulating periodization is best reserved for strength training, as it was initially intended. Unlike running, strength training has a narrow focus regardless of how it’s done, whether for muscular endurance, hypertrophy, or muscular strength. Running has a much wider focus that incorporates many body systems and can be done from very slow for hours to very fast for seconds, which represent completely different stimuli and adaptations. My experience supports that it’s better to narrow the focus on one or two stimuli, habituate to that stimulus through repetition, and then increase the stimulus (via increases in volume, intensity, or volume of intensity), which requires a linear, reverse linear, or block periodization approach.   

Part 4 of this series on periodization will discuss the special circumstances of high school and college periodization.

Dr. Jason Karp is a coach, exercise physiologist, bestselling author of 15 books and more than 400 articles, and TED speaker. He is the 2011 IDEA Personal Trainer of the Year and two-time recipient of the President’s Council on Sports, Fitness & Nutrition Community Leadership award. His REVO₂LUTION RUNNING coaching certification, which has been obtained by coaches and fitness professionals in 26 countries, was acquired by International Sports Sciences Association. In 2021, he became the first American distance running coach to live and coach in Kenya. Running Periodization and his other books are available on Amazon.


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