One Repetition Maximum
This one is a bit of a nerdy read but just as important for any given training program. For those of you that don’t like math, take your frustrations out at the gym and not on us please!! So lets get to it, shall we?
1RM or one repetition maximum is the term that is used to indicate the maximum weight an individual is capable of lifting in a single repetition of a particular movement or exercise. It is commonly referred to as 1RM.
Maximums are the base value used to build any weight training program. After calculating your maximum weight, you can use this figure and percentages of it to plan your training with set objectives: developing explosive strength, increasing power, increasing speed, toning, increasing muscle mass etc.
There are several ways to calculate maximum weights, using direct and indirect methods and different procedures. There are various weight training protocols which call for lifting some percentage of the lifter’s 1RM. However, many consider the risk of injury a possibility when attempting a 1RM to be equal to or higher than when performing multiple rep sets. As a result, there have been various proposals for ways to calculate an approximation of the 1RM.
Below are the two most common formulas used to calculate the one rep maximum. If r is the number of repetitions performed and w is the amount of weight used, then use Formula 1 below.
The second formula is a bit more involved. Have a look below.
Formula 2
This version of the one rep maximum calculation is often referred to as the Brzycki Formula after its creator, Matt Brzycki, and can be written either in terms of integers or decimal approximation:
Hey, we warned you about the second formula!!
Both of the formulas have similar results for 10 repetitions. But if the reps are less than 10, formula 1 will have a slightly higher estimated maximum. So if you want to impress the ladies, stick will the first formula! Here is a good example. If a person is able to lift 100 pounds on a given exercise for 10 reps, the estimated one rep max would be 133 pounds for both of the formulas. If the person was only doing 6 reps, then the first formula would estimate a one rep maximum of approximately 120 pounds, while the second formula would return an estimate of approximately 116 pounds.
These types of calculations will not always produce accurate results but are good to use as starting points. The weight can then be changed as needed to perform the number of reps called for by the training protocol.
Several more complex formulae have been proposed which use different coefficients for different rep numbers and sometimes even for different exercises. But we’ll save that for another time. Just writing this gave me a headache!


