The 80/20 rule for improving endurance performance

In the world of triathlon, training philosophies are abundant. Often, a training program appears to have more credibility because of its complexity. While a focused and organized training plan is crucial to improve performance, its structure need not be complicated. Herein lies the basic concept of the 80/20 rule, a training philosophy that is followed by the majority of elite athletes around the world. What follows is a brief, non-complicated, review of the 80/20 rule from a study by Seiler and Tønnessen1.

The 80/20 rule consists of two types of endurance training intensities: Low intensity training (LIT) and high intensity training (HIT). LIT, or what is commonly referred to as long slow distance, is defined as a training session that is greater than 30 minutes, below lactate threshold, and at 60-75% of your VO2max. Conversely, HIT, or interval training, are repeated bouts of exercise lasting 1-8 minutes, performed at 90-100% of VO2max, and separated by a recovery period.

Interval training has been around since the 1920’s and the debates about which has a greater effect on performance, HIT v. LIT, has been argued for nearly as long. What is agreed, however, it is that LIT promotes peripheral adaptations (improved movement economy, increased number of mitochondria, improved lactate threshold) and HIT promotes central adaptations (greater cardiac stroke volume, improved buffering capability of lactate).

The 80/20 rule states that 80% of an athlete’s training volume should be LIT while 20% of training volume should be HIT.

To simplify, consider the two intensities as very hard intervals v. very easy training. And for those who train using heart rate zones, LIT falls into Zones 1-3 and HIT falls into Zones 5+.

How well is the concept of the 80/20 rule used by athletes? Several studies show that elite endurance athletes, from collegiate 200m swimmers to Olympic marathoners, adhere quite well to the 80/20 rule. For example:

--Swimmers: 77% of volume was between Zones 1-3. These are very easy training intensities despite the fact they are preparing for a high intensity race.

--Marathoners: 78% of volume was BELOW marathon pace. 18% at 3K pace. Again, the majority of a marathoner’s training was completed at relatively low intensities.

--Elite Kenyan 10k runners: 85% training volume was BELOW lactate threshold.

This shows that the vast majority of an elite athlete’s training volume is of low intensity (Z1-3) and a relatively small volume is at a very high intensity (Z5+).

In contrast, case studies show that age group athletes do not follow the 80/20 rule, even when they are coached to do so. Age group athletes spend too much time training at lactate threshold (Zone 4) and not a proper amount of time training at either HIT or LIT. A review of age grouper’s training logs show the following distribution of training intensities:

Z1-3: 31% of training volume: Too little LIT

Z4: 56% of training volume: Too much threshold training

Z5+: 13% of training volume: Too little HIT

There is a lesson here that age group athletes can learn from their elite athlete counterpart, and that is…

Age group athletes run too hard on easy days,

Run too easy on hard days,

and spend too much time at lactate threshold.

To summarize,

“The available evidence suggests that combining large volumes of low-intensity training with careful use of high-intensity interval training throughout the annual training cycle is the best-practice model for development of endurance performance.”2

So consider the 80/20 rule when constructing your next training block, or talk to your coach for additional details. Be confident that a balanced training plan of LIT and HIT will produce long-term performance improvements. Do not think of LIT training as “junk miles”. On the contrary, LIT is instrumental in laying the fabric and infrastructure to support HIT. Without low intensity training, your high intensity training has nothing to stand on.

Chris Toriggino

coach. founder.

Athlete Architecture

Building Endurance Athletes

1,2 Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training

Stephen Seiler1 and Espen Tønnessen2

Sportscience 13, 32-53, 2009 (