1RM — one-repetition maximum

Muscle Strength Test

A tool for assessing the strength and endurance of muscle groups, used in sport, rehabilitation and medical diagnosis.

  • 15 to 20 min
  • Spotter recommended
  • Barbell + plates

Overview and principle

A muscle strength test measures the ability of a muscle or muscle group to generate maximal force against resistance. It can be assessed through manual testing (resistance applied by a practitioner), isometric testing (contraction with no change in muscle length, e.g. with a dynamometer) or functional testing (everyday movement patterns).

The most common test at home is the 1RM: the maximum load a person can lift a single time for a given exercise.

Calculator

Estimate your 1RM (Epley formula)

Formula: 1RM = weight × (1 + 0.0333 × number of repetitions).

Estimated 1RM
kg

Doing the test yourself

Equipment needed:

  • A barbell or dumbbells
  • Adjustable weight plates
  • A weight bench (for certain exercises)
  • A spotter for safety during maximal-load attempts

Protocol

How the 1RM test unfolds

  1. Starting weightChoose a starting weight based on your usual training level.
  2. Preparatory setPerform a first set with a moderate weight to prepare your muscles.
  3. ProgressionIncrease the weight gradually, attempting a single complete repetition at each step.
  4. Rest between attemptsRest 3 to 5 minutes between attempts to allow optimal recovery.
  5. RecordingNote the maximum weight lifted correctly a single time.

Other types of muscle strength tests

Manual testing and the MRC scale: often used by physiotherapists, grading strength from 0 (no contraction) to 5 (normal strength).

Isometric testing: measures the force produced without any change in muscle length, typically using a dynamometer.

Functional testing: mimics everyday or sporting actions (carrying loads, climbing stairs) to assess strength and endurance in real-life situations.

Recommended gear

To run the test in good conditions

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Frequently asked questions

FAQ

What is the 1RM?

The 1RM (one-repetition maximum) is the maximum load a person can lift a single time for a given exercise.

Is the Epley formula accurate?

It is an estimate based on a submaximal load and a number of repetitions, useful for avoiding a risky direct max-load attempt. It remains an approximation, not an absolute value.

What is the MRC scale for manual testing?

The Medical Research Council scale grades strength from 0 to 5: 0 = no contraction at all, 5 = normal strength. It is used by physiotherapists for manual muscle testing.

Should you test your 1RM by lifting the maximum load directly?

No, that is not advisable without experienced supervision: the Epley formula estimates your 1RM from a submaximal load, which reduces the risk of injury.