The Brown 1RM Formula
The Brown formula offers a straightforward linear method for estimating one-repetition maximum (1RM) strength based on submaximal lifts. Originally introduced in an educational setting, it remains a simple and practical tool for coaches, students, and strength athletes alike.
H. Larry Brown: Educator and Fitness Advocate
H. Larry Brown is a longtime professor and author in the field of physical education and health science. He taught exercise physiology and fitness instruction at American universities throughout the 1980s and 1990s and was known for his accessible, applied approach to fitness education. Brown authored several editions of the widely used textbook Lifetime Fitness, where he introduced his 1RM estimation formula as a teaching tool for strength assessment. Brown’s work focused on promoting fitness as a lifelong habit and on providing practical methods for exercise prescription without the need for maximal exertion tests. His writing aimed to bridge the gap between academic principles and everyday training practice, particularly in educational settings where safety and simplicity are key.
Origin and Development
The Brown formula was first published in Lifetime Fitness (3rd ed., 1992), a textbook designed to support general fitness education at the college level. The formula was presented as a practical means to estimate 1RM without requiring trainees to perform maximal lifts. Unlike formulas derived from formal regression studies or scientific trials, Brown’s equation was not presented with statistical backing or a detailed description of its derivation. Instead, it was likely based on empirical coaching norms or interpolated from earlier one-repetition maximum charts. Despite its informal origin, the formula gained traction and has been cited in both academic and coaching literature as one of the classic 1RM estimation models.
The Brown Formula
The Brown formula estimates 1RM with the equation:
1RM = w × (0.9849 + 0.0328 × r)
Note that some sources incorrectly state the coefficient as 0.0338, likely due to typographical errors or confusion with similar linear formulas like Epley, which uses 0.0333. The correct coefficient, as published in Lifetime Fitness, is 0.0328.
Where:
- w is the submaximal weight lifted
- r is the number of reps performed to fatigue
Example:
If you lift 100 kg for 5 reps:
1RM = 100 × (0.9849 + 0.0328 × 5) = 100 × (0.9849 + 0.164) = 100 × 1.1489 ≈ 114.89 kg
Thus, the estimated one-rep max is approximately 115 kg for this athlete’s bench press.
Note that the 0.0328 coefficien.
Validation and Accuracy
While Brown’s formula lacks formal documentation of its derivation, it has been included in multiple academic comparisons alongside other well-known formulas such as Epley, Brzycki, and Wathen. In a 2008 study by Kemmler et al., the Brown formula was evaluated for its accuracy in predicting bench press 1RM among trained college-aged women. It performed well, overestimating the true 1RM by only about 0.9 kg on average (≈3.7% error), with high correlation to actual performance. A 2024 study by Ribeiro et al. also included the Brown formula in a comparison of estimation methods. Their findings suggested that it was among the most accurate formulas for predicting squat and bench press 1RM in women, closely matching actual measured values in most cases. A 2009 study by Knutzen et al. found higher average errors for Brown compared to Mayhew, Epley, and Wathen, ranging from 7-17% across exercises. Overall, Brown’s formula appears to be a reasonably conservative and reliable estimator in the 2-10 repetition range, particularly for compound lifts like bench press and squat, but less accurate for high reps (>10) or isolation movements.
Brown’s Legacy
While not as widely known as some other strength researchers, H. Larry Brown made a lasting contribution to strength training education through his textbooks and the Brown formula. His work reflects the broader shift in the 1980s-1990s toward making fitness accessible, measurable, and safe for everyone. The continued use of his formula in academic studies and training calculators speaks to its lasting utility.
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