Reps at 80% 1RM? Can They Be Useful for Individualizing Reps-Max Table?

The more weight you put on the bar, the less reps you are able to do. This is common knowledge and a phenomena we want to describe, predict and intervene upon. Although this relationship tends to differ between individuals and exercises (as well as single individual and single exercise across time), we often utilize heuristic (i.e., rules of thumb) equations and tables to help us get oriented and provide some meaning while sacrificing precision. One such heuristic is Epley’s equation, made popular by Jim Wendler and his 5/3/1 book series (Equation 1).

\begin{split}
\%1RM = \frac{1}{0.0333 \times nRM + 1}
\\\end{split}

Equation 1 can be converted to a table, for easier utilization (Table 1).

Table 1: Epley’s reps-max table

Although imprecise, Table 1 can be quite useful if you are dealing with bunch of exercises and individuals. At the end of the day, we do not aim for perfect accuracy.

There are other models that aim to map out this relationship (i.e., max reps and %1RM), and in the Load-Exertion Tables And Their Use For Planning article series, as well as the Create Custom Set and Rep Schemes With {STMr} course, I have outlined Modified Epley (Equation 2) and Linear/Brzycki (Equation 3) models.

\begin{split}
\%1RM = \frac{1}{0.0353 \times (nRM – 1) + 1}
\\\end{split}

\begin{split}
\%1RM = \frac{33 – nRM + 1}{33}
\\\end{split}

Table 2 enlist reps-max relationship using these three generic models.

Table 2: Reps-max table using the three generic models

All these are generic values, which are, as already explained, quite useful, but still imprecise. If you aim to create more precise individual reps-max equations (particularly for specialist lifters and few key exercises), you need to estimate these parameters (i.e., 0.0333, 0.0353, and 33 for the Epley’s, Modified Epley’s, and Linear/Brzycki’s equation respectively) using either (1) few sets to failure (e.g., with 90, 80, and 70% of 1RM), or (2) utilize novel technique of training log analysis explained in the Create Custom Set and Rep Schemes With {STMr} course.

There is a simple(r) way to do that. Not very precise, but again, a step toward more precision without too much burden of doing multiple sets to failure across one or more days. This is simply doing maximum reps at 80% and adjusting the tables accordingly. Perfect? Nope. But easy, doable, and useful.

Table 3 enlist estimated model parameter values (i.e., those 0.0333, 0.0353, and 33 in the Equation 1, Equation 2, and Equation 3 respectively) depending on the maximum number of repetitions performed at 80% 1RM.

Table 3: Model parameter values depending on the maximum number of repetitions at 80% of 1RM

Although you can plug these parameter values into the equations, it is easier to create reps max tables based on the max repetition at 80% 1RM. These can be found in Table 4, Table 5, and Table 6 for the each model respectively.