What is the definition of 1 Rep Max (1RM) and what does it mean?
1 Rep Max Definition
1 Rep Max (also know as One Repetition Maximum or 1RM) is the standard measure of muscular strength. 1 Rep Max measures the maximum amount of weight that a given muscle can move through a complete contraction (eccentric and concentric) one time, with good form.
1 Rep Max is used in weight training to determine maximum strength and as a way to calculate the upper strength limits when developing a weight and resistance training program. In these cases, a percentage of 1RM may be used to develop target load levels for measuring and/or improving things like muscular endurance (typically 75-90% of 1RM.)
1 Rep Max is also used as a method for determining winners in power-lifting and weight lifting competitions, including Olympic power lifting.
Methods for Testing and Determining 1 Rep Max/1RM
One Rep Max is typically determined one of two ways:
- Direct Measure 1RM: Observing a person performing a lift under maximal resistance and then recording the 1RM
- Predictive 1RM: Calculating an estimated 1RM using a mathematical formula, such as the Brzycki Formula. Predictive models use performance on sub-maximal lifts (where you perform more than one repetition with a lighter weight) to determine maximum load.
Because the risk of injury when performing 1 Rep Max lifts may be greater than when performing sub-maximal, multiple-rep lifts, many trainers will use a predictive 1RM model to calculate approximate 1 Rep Max.
Additionally, because most people perform multiple repetition resistance exercises, they may not actually know what weight to start with to measure 1RM. Predictive formulas can supply a starting point for direct measurement of 1 Rep Max.
Risks Associated With 1 Rep Max Lifts
Attempting an actual 1 Rep Max lift should only be done by individuals who are already in good physical condition, are properly warmed-up and in the presence of a strong, experience spotter or trainer available to assist if needed.
Individuals with pre-existing medical conditions or prior injuries should generally avoid 1 Rep Max lifts.
Category: Fitness, Health & Exercise Glossary