1Rm

1RM stands for one-repetition maximum, the greatest amount of weight that can be lifted for a single repetition of a given exercise with proper technique. It is a common measure of maximal lower- or upper-body strength and is used to guide training loads, track progress, and compare performance across individuals or time.

In practice, 1RM is used to prescribe training intensities as percentages of the maximum lift. Programs often base sets and reps on a percentage of an individual’s 1RM, and improvements in 1RM are commonly used as a key strength metric. It is most relevant for exercises such as the squat, bench press, deadlift, and overhead press, though its applicability varies by sport and goal.

Determining a 1RM can be done directly or estimated. Direct testing involves a structured warm-up followed by progressively heavier attempts until one lift fails to complete with proper form. Rest between attempts is important, and safety equipment, supportive spotting, and a stable rack or platform are essential. Because direct testing can be risky, it is often avoided by beginners or individuals with injuries.

If direct testing is unsafe or impractical, submaximal testing or estimation formulas are used to predict 1RM from a higher-repetition lift. Common formulas include Epley (1RM = weight × [1 + reps/30]) and Brzycki (1RM = weight × 36 ÷ [37 − reps]). For example, lifting 100 kg for 5 reps yields an estimated 1RM of about 116.7 kg with Epley.

Limitations include technique dependence, exercise specificity, and variability between individuals. 1RM does not reflect endurance, technique quality, or muscular size, and or applicability across all movements.