Jan 29, 2015
Resting to Win

The practice of tapering is common among endurance athletes, but it is often misunderstood. Our expert offers advice on how best to apply the latest research.

By Dr. Guy Thibault

Guy Thibault, PhD, is an Associate Professor in the Kinesiology Department at the University of Montreal and a scientific advisor to the Canadian Cycling Association. He has developed a physiological model of running performance and an empirical model of interval training for all endurance sports. He is also the former coach of Boston Marathon winner Jacqueline Gareau, and can be reached at: [email protected].

When preparing for an important competition, every athlete wants to raise his or her performance a notch. In endurance sports, coaches have used the concept of tapering for many years to achieve this. The basic premise is to reduce the amount of training athletes do leading up to a competition so that they peak at just the right time.

The problem many coaches run into, however, is that they follow this basic premise but execute it the wrong way. Physiologists who have studied tapering have produced much new research on how to make it work. Approximately 60 scientific studies have been authored testing a range of tapering patterns, most involving runners, cyclists, swimmers, and rowers.

The studies show that athletes can make significant performance gains using an effective tapering plan. Often these gains represent more significant performance improvement than an athlete sees following a whole season’s worth of training. However, a poorly designed plan can lead to a frustrating downturn in performance and poor results during competition.

Many coaches and athletes think they can trust their own experience and instincts to find the right approach. But in reality, because performance depends on so many elements that are difficult to control and to quantify, it is much better to base a tapering program on the best available physiological knowledge.


Without question, endurance training improves physical condition, but it also induces fatigue. Leading up to an important competition, the main goal of a tapering program should be to reduce the athlete’s level of fatigue while maintaining their physical conditioning. In a nutshell, the most effective tapering system is the one that results in lots of rest but very little detraining.

The biggest question coaches usually have about developing a tapering program is whether it’s better to reduce volume or intensity during tapering. The latest studies make it clear that the most effective tapering methods involve reducing the volume of training that is performed at low intensity, and maintaining the volume of training at high intensity.

This training philosophy contradicts many athletes’ and coaches’ natural inclinations. For example, cross country runners who give up their high intensity work and go out for a long, gentle jog in the last few days before an important race may become a bit less fatigued, but it has been proven that their physical conditioning will suffer, and their performance will show it.

Here are more specifics, backed by scientific studies:

• The frequency of daily training sessions should remain unchanged, or should be reduced by only a very small amount. If your athletes train five days a week, they should continue to follow that schedule.

• The total volume of training should be drastically reduced–by around 50 percent. For example, an athlete who normally trains for 10 to 12 hours per week should train five to six hours in the week leading up to an important competition.

• The global difficulty level of each training session should be reduced.

• The volume of high-intensity effort should remain high. That means the periods during which the athlete trains at a higher intensity should be maintained. In this context, “high-intensity” means an intensity higher than that of a long, continuous outing, but lower than all-out sprinting.

• The activity practiced during the tapering period must be specific to the athlete’s sport. For example, the run-up to a marathon is not the time for cycling or swimming workouts.

• Athletes should not perform any activity that could provoke delayed-onset muscle soreness, such as weight training or anything else requiring a large amount of eccentric muscle contractions. Doing so can lead to a temporary reduction both in muscular strength and the replenishment rate of muscle glycogen reserves.

To sum it up, athletes should train for the same number of days as usual, but with shorter, less difficult workouts. However, during those shorter workouts, continue high-intensity work within the athlete’s particular discipline.


You probably want to know exactly how to adjust the difficulty during tapering. Unfortunately, researchers who have studied the effects of various tapering systems have not been particularly concerned with measuring each training session’s level of difficulty–which is hard to quantify anyway.

Therefore, no formal recommendations exist for how best to structure a training session during the lead-up to an important competition. However, there is reason to believe that the level of difficulty should be progressively reduced during the taper phase.

Many coaches also wonder how you make sure the level of training difficulty is low enough without reducing the volume of high-intensity efforts too much. The key here is to adjust the parts of the sessions that do not involve high-intensity effort. Here are some suggestions:

• Arrange the interval training sessions in several sets. • Allow for a long, inactive period of recuperation rather than an active one in between repetitions during interval training. • Minimize warmup and cooldown periods. I suggest they last five minutes each.

During the taper period, athletes feel as if they are bursting with energy and they will want to pursue a higher volume of training. However, coaches should not allow this!

If the total volume of training is not significantly reduced, there is no overcompensation, and therefore no peak in performance. By participating in training sessions that are intense, but not too long or difficult, endurance athletes will optimize their performance by maximizing their fitness and minimizing their fatigue.

In developing a plan, it’s important to understand that “difficulty” is not the same as “intensity”–in fact, the concepts are quite different. A training session that includes bouts of effort at a high intensity, such as running quarter-mile intervals at 100 percent of VO2 max, is not necessarily difficult if the number of intervals is not very high, recovery periods are long enough, and the intervals are split up into several sets with sufficient recuperation in between. By contrast, a low-intensity session, such as at 65 percent of VO2 max, might be very difficult if the session is long and takes place on the day following a particularly grueling competition.

One more detail has to do with nutrition. During the tapering period, athletes should change their diet slightly, reducing the overall number of calories. Reduced training volume means reduced energy expenditure, so fewer calories are needed. If athletes do not slightly reduce their calorie consumption, they will gain weight, which may hamper performance. If an athlete is preparing for an event that lasts longer than 90 minutes, he or she should also consume more carbohydrates while restricting the intake of fatty foods in the last four days leading up to the event.


Another important aspect of tapering is timing. A tapering period should last about a week–slightly more if the volume of training is reduced progressively (which seems to give better results), slightly less if it is reduced abruptly.

Increase the tapering period further for athletes older than 30 or 35. Studies show that older athletes need more time to recuperate and thus will benefit from a longer taper. For instance, give them an average of 10 days of tapering rather than seven.

Although there is no research to back this up, many coaches believe that the taper should be longer for athletes whose preparation has been particularly long and arduous. It has also been suggested that women benefit from a longer taper more than men do, but there is no scientific evidence to support this.

Timing becomes trickier if an athlete is training for two important events scheduled close together, both of which they want to achieve optimal performance for. Maybe they need to peak for the track and field regional competition, and again a week later for nationals. Or possibly a crew athlete is preparing for an important team race, then has an elite-level team tryout scheduled four weeks later.

There is no tested formula for these situations, only some good general guidelines. If an athlete has two important competitions scheduled less than three weeks apart, it is probably best to continue the reduced-volume program while maintaining a substantial volume of high-intensity efforts. If the period between the two competitions is longer, it is a good idea to increase the volume as soon as the athlete has recovered from the first important race, then reduce it progressively as the second event approaches, while at the same time maintaining a substantial number of high-intensity efforts.

It is not a good idea to schedule tapers for an athlete several times in one year. Since a taper is most effective if it is preceded by a progression phase and then an intensive phase–which requires several weeks to run full-cycle–an athlete simply cannot taper again and again and meet optimum performance goals each time. Athletes also should not be placed in situations where the volume of their training is greatly reduced too often.


Experts generally agree that a taper has the most potential for success if it is preceded by a period of two to three weeks of particularly intense training. This can include competitions (both real and simulated), intense interval training sessions, and rigorous endurance work. An intensive period should be preceded by a period of progression lasting at least eight weeks, during which the athlete establishes a base necessary for carrying out the intensive phase of training.

Here is a checklist coaches can use to assess the quality of the progression and intense training phases leading up to the taper:

• An annual plan must be divided into individual phases (two to six weeks) comprising key performance factors that serve as points of emphasis.

• Training sessions must be designed to stress each of the key performance factors for the specific event the athlete is preparing for.

• There must be a progressive evolution of each element that makes up the total training load.

• Intensive sessions should focus on developing just one or two key performance factor(s).

• Emphasis should shift between volume and intensity.

• Certain interval training sessions can comprise more than 20 bouts of effort, while others can comprise fewer, yet much longer intervals.

• Training conditions should mimic the variables the athlete is likely to encounter during the competition.

• There should be three to five days of active rest following harder training periods (of a few weeks).

• Sessions that demand extreme efforts of short duration should only be planned for moments when the athlete’s fatigue level is low.

• In each training phase, there must be a number of sessions devoted to reinforcing the qualities developed in previous phases.

The items in this checklist won’t be new to most veteran coaches. Most of us know how to design the right progressions under the right conditions to achieve gains. But what many coaches don’t know is that these progressions are critical to making the taper work. The progression of training must work hand-in-hand with the taper.

For example, even a well-designed taper can provoke a significant drop in performance some weeks later. In reducing the volume of training during the taper, you reduce the training stimulus, which can be accompanied by a temporary lowering of physical capacity, which you do not want to do too often. However, negative effects accompanying a reduction in training volume is usually the result of an endurance athlete not doing enough training before the taper. It is not the taper’s fault, but rather a lack of work before it.

In contrast, it has been demonstrated that performance levels for overtrained athletes continue to improve during the days and even weeks following the competition for which they tapered. So for overtrained athletes, the taper isn’t long enough to obtain peak performance as they are still recovering when the day of competition arrives.

As you look forward to your most important competitions of the year, make sure your tapering program is a help and not a hindrance. The keys to making it work are having proper progression and a solid week of less difficult, but high-intensity workouts before the big event.

Recommended Readings

Mujika I., S. Padilla, et al. “Physiological Changes Associated With the Pre-Event Taper in Athletes.” Sports Medicine 13, no. 34 (2004): 891-927.

Péronnet F., G. Thibault, et al. Performance In Endurance Events. Spodym Publishing, 1987. p. 272.

Thibault G., “Ahead of the Pack.” Training & Conditioning 16, no. 3 (2006): 25-31.

Thibault G. and A. Marion. “Tapering and Maximal Performance: A Physiological Perspective.” Coaches Report 2, no. 3 (1996): 13-8.

SIDEBAR: Endurance Answers

Last year, Dr. Thibault wrote an article for Training & Conditioning that described a unique “Interval Training Model” he has developed. Here, he answers questions some of our readers had on the model and on his vision of what exactly endurance is.

Do all great long distance athletes necessarily have high endurance?

No! Lots of high performance champions actually have quite poor endurance. We measured the endurance of 2,464 runners and found that the correlation between their endurance and their performance in long distances (even the marathon) was very weak. This means that among our elite distance athletes, some have high endurance and some have low endurance.

Over a three-hour event, more than 70 percent of performance can be explained by MAP and less than 20 percent by endurance. So it seems that an athlete with low endurance can succeed in endurance events, as long as he or she has a high MAP.

Does that mean developing endurance is not important?

Most of the time, when people use the term endurance, they refer to the ability to exercise at high intensity over a long distance. But this ability depends much more on MAP than on endurance. So, although it is extremely important to develop MAP, I’m not sure it is even possible to improve endurance when you have already completed a minimum amount of training.

Generally, in order to improve endurance, high performance coaches recommend doing interval-training sessions with bouts of effort at 75 to 95 percent of VO2 max. Of course, such training sessions will improve aerobic performance. But studies must be done to verify if this type of training really improves performance by influencing endurance or MAP. Several field observations lead me to believe that those training sessions improve performance over long distances by boosting MAP much more than endurance.

What is the secret to preparing for long distance races without spending hours and hours training? The ability to exercise for a long period of time is quite easy to develop, as long as you do long outings regularly and follow a decent progression in their length. Once this is developed to a certain level, you can focus on interval training. In fact, doing more long outings sucks out energy that would be better spent on developing MAP. An athlete who does interval training sessions to improve MAP will end up finding it easy to exercise at a high velocity for long time periods, because MAP is the key performance factor. Appropriate interval training sessions will certainly bring greater improvements than long outings, because the latter are done at an intensity that is too low.

How often should you assess your athletes’ MAP?

Since MAP may increase at an average of approximately two watts per interval training session (ITS) derived from the model, it would be wise to assess MAP each time an athlete has completed five ITS. The last time I made a study to validate the model, I tested the subject every 10 “hard” outings, and the improvement of MAP between assessments was always 20 watts, from 380 to 400, then to 420, and finally to 440 watts.

How did you come up with your vision of endurance?

Thibault: While earning my doctorate in exercise physiology, I developed a physiological model of running performance. It shows the link between the physiological qualities of an athlete and his or her performance over a wide range of running distances. The key performance factors are maximal aerobic power (MAP, which is one’s power output when VO2 max is reached) and anaerobic capacity, but also endurance, which is the capacity to sustain a high fractional utilization of VO2 max for prolonged periods of time.

In order to investigate the physiological factors associated with endurance, we had to develop an adequate index. We proposed a way to quantify endurance in running and this approach can also be applied in other “aerobic” sports, such as cycling, swimming, rowing, and so forth.

How exactly do you define and assess endurance?

Endurance is generally defined as the capacity to sustain a high percentage of VO2 max for a prolonged period of time. But this definition does not allow adequate comparisons between two athletes except in two specific and limited conditions. It allows adequate comparison only if they have different fractional utilization of VO2 max over a given racing time (e.g., 80 versus 85 percent of VO2 max over a one-hour track event), or the same fractional utilization of VO2 max over different racing times (e.g., 80 percent of VO2 max over 60- and 75-minute track races). However, in the majority of cases, the information available is the fractional utilization of VO2 max: (i) on a given racing distance covered in different racing times (e.g., 72 versus 83 percent of VO2 max over a marathon completed in 3:12:24 or 2:58:19, respectively); or (ii) on different racing distances run in different racing times (e.g., 88 percent of VO2 max on a 10 km race run in 31 minutes versus 79 percent of VO2 max on the marathon run in 3:08:31).

One can observe that the reduction of fractional utilization of VO2 max has a linear relationship with increasing racing time for races longer than seven minutes if times are expressed on a natural logarithmic scale. So, to measure your endurance, you first must perform at least two time trials under ideal and similar conditions that are greater than seven minutes long. You then calculate at what percentage of MAP you did each of these time trials (you must have done a MAP test previously). Finally, you draw a graph showing the relationship between percentage of MAP (on the ordinate) and the natural logarithm of the duration of the events.

For example, the graph below shows curves for three athletes. The black line athlete has average endurance, the red line athlete has an endurance corresponding to the average plus one standard deviation, and the green line athlete represents the average minus one standard deviation. These norms are based on data we collected from 2,464 athletes.

For any given racing time (irrespective of the race distance), athlete Red, with the greatest endurance (87.8 percent of MAP over a one-hour race versus 80 percent of MAP for athlete Green), sustains the highest fractional utilization of MAP. The slope of the relationship percent of MAP versus ln (t) is an index of the athlete’s endurance. This computation procedure for the endurance index can take into account several performances on different racing distances.


Suggested reading: Péronnet F. and G. Thibault. “Mathematical Analysis of Running Performance and World Running Records.” Journal of Applied Physiology 67, no. 1 (1989): 453-465.

To read his article in the April 2006 issue of T&C, log on to: www.training-conditioning.com/2007/03/ahead_of_the_pack.html.

Dr. Thibault’s Interval Training Model can be downloaded at: www.training-conditioning.com/GTgraph.pdf.


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