Guide to One Rep Max
What is One Rep Max?
One Rep Max (1RM) is the maximum weight you can lift in a single repetition while maintaining proper form. It is a fundamental parameter in strength training used for planning workout intensity and programming loads. Knowing your 1RM allows you to determine what weights to use at different repetition ranges, enabling systematic progress in training.
1RM percentages in training
- 100% - maximum weight, 1 repetition, used for testing
- 85-90% - maximal strength, 2-4 repetitions
- 75-80% - strength + mass, 6-8 repetitions
- 65-70% - hypertrophy, 8-12 repetitions
- 50-60% - endurance, 15+ repetitions
Calculation formulas
The most popular formulas are Epley (weight × (1 + reps/30)) and Brzycki (weight × (36 / (37 - reps)). The Epley formula is most commonly used and gives good results in the 1-10 rep range. Remember results are estimates - actual 1RM may vary depending on fitness, form, and exercise type.
Safety and testing
Testing 1RM should be done carefully, preferably with a spotter. Warm-up is essential - perform sets with decreasing weights before the max attempt. Don't test 1RM more often than every 4-6 weeks as it requires significant nervous system effort. For most training goals, calculating 1RM based on weight to failure is safer and sufficient.