How To Calculate Your One Rep Max Without Lifting Your Max

When designing a program, one of the most crucial variables that needs to be known by whoever is constructing the program is the lifters one rep max for all the primary lifts in which the program is built around, so that the most appropriate amount of weight can be selected to get the desired result.

Testing with hopes of finding a true max for any given lift has room for error, as well as an elevated risk of sustaining an injury. The room for error comes from the fact that fatigue from repeating efforts during the warm-up could negatively affect the outcome in terms of how much weight can really be lifted, whereas not warming up enough could result in catastrophic injury.

Fortunately there are other ways to determine a rough estimate of what ones maximum is based on how many reps can be performed with a given amount of weight. Obviously if only one rep can be performed, it is without a doubt the momentary maximum, but that’s not to say an additional pound or two could've been tacked on. Below is a chart to help determine what your maximum would be if you performed:

2 reps = 97%

3 reps = 94.5%

4 reps = 91.5%

5 reps = 89%

6 reps = 86%

7 reps = 83%

8 reps = 80.5%

9 reps = 77.5%

10 reps = 75%

Keep in mind, these numbers are maxes, therefore if designing a program in which the goal is to perform more than one set for a given amount of reps, the amount of weight used likely needs to be reduced to account for the volume. Therefore, when prescribing several sets to be performed in a given rep range, a more conservative approach in terms of prescribed intensity may be necessary, looking like this:

sets of 2 = 95%

sets of 3 = 90%

sets of 4 = 87.5%

sets of 5 = 85%

sets of 6 = 82.5%

sets of 7 = 80%

sets of 8 = 77.5%

sets of 9 = 75%

sets of 10 = 72.5%

If you have any questions about how to calculate your one rep max, or how much weight should be used if the goal is to perform more than one set for a given amount of reps, feel free to contact me at ben@paramounttraining.ca. I'm available for online consulting and personalized program design, as well as one on one training if you are located in the Greater Toronto Area (GTA).