Alexander Sergeyevitch Prilepin was a weightlifting coach for the Soviets during the 1970's and 80's. During this time, he analyzed the training logs of many athletes and devised the Prilepin table which breaks out optimal rep ranges for olympic athletes per set and across an entire workout according to his own research. While the numbers are based off of olympic weightlifters, this table is very popular in the powerlifting community as well.

The Prilepin Table
The Prilepin Table provides guidelines for training in specific intensity zones.

A couple of problems emerge from Prilepin's chart that prevent it from being useful to the broader lifting community. First of all, it completely ignores sets with more than 6 reps. Secondly, it does not apply to workouts where your rep ranges change across sets. For example, if you performed a few sets at 5 reps, and a few sets at a higher weight using only one or two reps, your workout spans multiple rows of the chart and thus has two different suggestions for the optimal rep ranges.

Sumo Deadlift
The Prilepin Table has since been adopted by many powerlifters

Hristo Hristov noticed these problems and took the work of Prilepin a step further by devising the INOL (Intensity x Number Of Lifts) formula which gives us a relative measure of intensity across sets of different rep ranges. The formula is simply: Reps / (100 - Intensity) where Intensity is the weight lifted as a percentage of your one rep max. For example, if your max Squat is 300 pounds, and you performed 225 x 5 during one set, your INOL value is 0.2 computed as follows: 5 reps / (100 - 75). We use the value 75 as your intensity because 225 pounds is 75% of your max of 300 pounds.

The INOL formula is useful on it's own as a relative measure of intensity across sets, but it's real value lies when constructing new workout programs, or analyzing your efforts over time. Hristov provides very useful guidelines for your targeted INOL values per movement per workout and across an entire week:

Optimal INOL values per exercise for a single workout:

  • < 0.4 - too easy
  • 0.4 - 1.0 - optimal range for most athletes. An INOL value between 0.7 - 0.8 is a recommended starting point.
  • 1.0 - 2.0 - tough workout, but good occasionally, especially for loading phases
  • > 2.0 - very difficult and could lead to overtraining if performed regularly in most individuals

Optimal INOL values per exercise across an entire week:

  • 2.0 - easy, good for reloading, could probably benefit from greater volume occasionally
  • 2.0 - 3.0 - tougher, but doable, good for loading phases
  • 3.0 - 4.0 - very tough, good for shocking your body, but not recommended for extended periods of time
  • > 4.0 - not recommended

So you know how to compute your INOL values per set, and you have guidelines for the optimal INOL values you should target in your workout, let's walk through an example of how to apply these principles to your workout program. For this example, let's say we're on an Upper/Lower split and we workout 4 days a week so that we hit each muscle twice. We're going to target an INOL of 1.0 per workout and 2.0 per week per exercise when developing our program. We'll keep it very simple and say we're doing a very basic split of (Bench Press / Barbell Row) day 1 and (Decline Bench Press / Seated Row) for day 2. This gives us a horizontal pressing and horizontal rowing movement, of course we would likely add more movements to a real workout plan to hit the vertical plane of our shoulders and lats, but this is enough for our example.

To get our INOL values of 1.0, we have tons of options, here are a few examples:

  • 5x5 @ 75% 1RM
  • 3x8 @ 76% 1RM
  • 1x8 @ 60% 1RM, 1x5 @ 75%1RM, 1x3 @ 80% 1RM, 2x1 @ 95% 1RM

We could choose a rep range above, or devise an entirely different range that adds up to our target INOL of 1.0. To create a program, we just pick a rep range and apply it to each exercise in our program since we're only doing one lift per muscle group. If we had more exercises in our routine, we would group them by muscle group and then spread the load so that we hit each muscle equally and optimally. Since our program is very simple, our routine might look like the one below after we choose our rep ranges:

Upper A
Bench Press - 5x5 @ 75% 1RM
Barbell Row - 3x8 @ 76% 1RM

Upper B
Decline Bench Press - 1x8 @ 60% 1RM, 1x5 @ 75%1RM, 1x3 @ 80% 1RM, 2x1 @ 95% 1RM
Seated Row - 3x8 @ 76% 1RM

Some things to notice here are that we group exercises by their movement, so bench press (including incline or decline varieties) is grouped into one category whereas our horizontal pull movements are in a separate category that get's it's own INOL limits. In this way, you can target an INOL value of 2.0 for each muscle group during a single week to make sure you're targeting each part of your body with the optimal intensity levels.

While there is no perfect measure of intensity or mathematical formula that can work for everyone, we think this is a really interesting way to analyze your workouts. Learn more about Prilepin's chart or Hristov's methods from this reddit post, then be sure to let us know in the comments below how your workouts measure up to this formula. Are you already working out in the optimal range, or are you on the upper or lower end of the yard stick according to Hristov?

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Bryan Alger

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Bryan is the Co-Founder & CTO of Gravitus. A Marine Corps Veteran, the only thing he likes more than hacking on code is pumping iron.