Strength training
Lombardi Formula: Calculating 1RM on Longer Sets
The Lombardi formula uses a power relationship, useful for estimating 1RM when working with many reps.
What the Lombardi formula is and where it comes from
The Lombardi formula stands out for using a power relationship instead of a linear or rational model like the others. This mathematical structure gives it a particular behavior when estimating 1RM.
Thanks to that power relationship, Lombardi keeps some coherence even when the rep count is high, something linear formulas handle worse.
The formula and how to apply it step by step
The Lombardi equation is: 1RM = weight × reps^0.10. The 0.10 exponent makes the effect of reps grow smoothly and non-linearly.
Worked example: a client deadlifts 150 kg for 8 reps. 1RM = 150 × 8^0.10 = 150 × 1.2311 = roughly 184.7 kg. For a heavy reference set, Lombardi returns about 200 kg, a contained estimate.
Because it uses a power, it is best applied with a calculator: mental math is impractical compared with Epley or O'Conner.
When to use the Lombardi formula
Lombardi is especially useful in high rep ranges, where linear formulas tend to blow up the estimate. If your client trains with long sets, this formula gives more sensible results.
Strength
Stable behavior in high rep ranges, where other formulas overestimate.
Limitation
The exponent calculation is impractical by hand and it may be less accurate on very short sets.
Best use case
Estimating 1RM from muscular endurance or metabolic sets of 10-15 reps.
Comparison with the other four formulas
For the same heavy reference set, Lombardi returns about 200 kg, just like Brzycki, while Lander gives 202.8 kg, O'Conner 205 kg and Epley 206.7 kg.
Lombardi usually lands on the conservative side alongside Brzycki. Its real advantage is not in this single example but in how it behaves when reps climb high: it keeps a cool head while linear formulas spike.
How to use 1RM in your clients' programming
If you program muscular endurance work, Lombardi gives you a realistic reference 1RM to set percentages even when you do not test with heavy loads. Combine it with RPE to fine-tune effort on long sets.
In TrainerStudio you store each exercise's estimated 1RM and use it to prescribe coherent loads across endurance, strength or hypertrophy blocks, logging the real progression.