American Council on Exercise by American Council on Exercise

Resistance training is important for increasing muscular strength and muscle mass, and improving bone density. While demonstrating and teaching good technique is paramount, it also is important that trainers are able to properly evaluate how much weight clients should be lifting, both to effectively stimulate the muscle and to avoid injury.

One way of measuring the amount your client can lift is to use % RM—repetition maximum.

Experienced weight trainers and athletes can lift weights that correspond to a percentage of their 1RM. To do this, you must first perform a 1RM test to determine the maximum amount a client can lift in one repetition. You can then use this weight value to calculate the % RM and determine recommended training volumes based on the client’s goals (Tables 1 and 2).

Table 1. 1 RM – Repetition Table

Repetition Table
 Baechele, T.R. and Earle, R.W. (2008).
Essentials of Strength Training and
Conditioning (3rd ed.).Champaign,lll.:
Human Kinetics.

Table 2. Recommended Training Volumes

Recommended Training Volumes

Baechele, T.R. and Earle, R.W. (2008). Essentials of Strength Training and Conditioning (3rd ed.).Champaign, lll.: Human Kinetics.  Westcott, W.L. (2003). Building Strength and Stamina (2nd ed.). Champaign, lll.: Human Kinetics.  

Lifting maximum weight loads and completing 1RM assessments are not appropriate for most people because of the risk of injury. For safe and effective resistance training, the American College of Sports Medicine (2009) recommends that the average, healthy person perform at least one set of eight to 12 repetitions (or lifts) of a weight that feels challenging by the last couple of repetitions.

For the client who cannot complete maximum lifting, start with a weight they can comfortably lift and gradually increase the weight until they find a weight that feels challenging by the last couple of repetitions of the rep range. Once you have determined a safe weight for them at eight to 12 repetitions, you can then use the Repetition Table (Table 1) to predict the weight for higher intensities or a maximum-lift prediction.

For example, you have a client who is performing a bench press and you have determined that he or she can lift 80 lbs up to the 10 rep mark. Using the repetition table, 10 reps equals 75% RM; therefore, your client’s predicted would be: 1RM = 80 ÷ 0.75 = 107 lbs

To learn more about how to measure 1RM, please read pages 221-230 in the ACE Personal Trainer Manual(4th Edition). For more helpful information, read our Predicted 1 RM vs. Actual 1 RM blog.