To calculate the maximum weight I can lift (1RM), I use various formulas. The Brzycki, Epley, and Lander formulas yield pretty accurate results, while the Lombardi and O’Conner formulas tend to underestimate, and the Mayhew and Wathan formulas overestimate.
Formulae
- Brzycki:
weight × (36 / (37 - reps)) - Epley:
weight × (1 + 0.0333 × reps) - Lander:
(100 × weight) / (101.3 - 2.67123 × reps) - Lombardi:
weight × reps ^ 0.1 - Mayhew et al.:
(100 × weight) / (52.2 + (41.9 × e-0.055 × reps)) - O’Conner et al.:
weight × (1 + 0.025 × reps) - Wathan:
(100 × weight) / (48.8 + (53.8 × e ^ -0.075 × reps))
You can read more about these formulas in this NIH article.