In resistance training, 1RM (1 Repetition Maximum) represents the maximum weight you can lift for a single, proper repetition. Knowing your 1RM is essential for preventing injuries and setting optimal working weights for strength or muscle hypertrophy.

Standard 1RM Formulas (Epley & Brzycki)

Attempting a true 1RM test frequently carries a high risk of injury. Instead, you can estimate your 1RM safely by using the weight lifted (W) and repetitions performed (r).

1. Epley Formula (Widely Used Standard)

1RM = W × (1 + r / 30) # Example: 80 kg lifted for 8 reps 1RM = 80 × (1 + 8 / 30) = 80 × 1.266 = ~101.3 kg

2. Brzycki Formula (Accurate for ≤10 Reps)

1RM = W / (1.0278 - 0.0278 × r) # Example: 100 kg lifted for 5 reps 1RM = 100 / (1.0278 - 0.0278 × 5) = 100 / 0.8888 = ~112.5 kg

Working Weight Target Percentages (% of 1RM)

Once you estimate your 1RM, choose your working weight range based on your primary training goal:

  • Maximal Strength & Power: 85% to 90% of 1RM (3–5 reps per set)
  • Hypertrophy (Muscle Growth): 70% to 80% of 1RM (8–12 reps per set)
  • Muscular Endurance: Under 60% of 1RM (15+ reps per set)

The Importance of Consistent Workout Logging

Tracking reps and weight across every session allows you to monitor and apply Progressive Overload effectively. Instead of messy paper notes, use Athlentic to log every set, weight, and rest timer effortlessly on your iPhone.

Track Weights & Sets Seamlessly with Athlentic

A clean, intuitive iOS fitness logger built for tracking sets, weights, and rest timers.

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