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Predicted 1 RM vs. Actual 1 RM

Predicted 1 RM vs. Actual 1 RM | American Council on Exercise | Exam Preparation Blog | 9/17/2012


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Bench PressProper foundational and physiological assessments are essential to program development and evaluation throughout every client-trainer relationship, and knowing how and when to use proper assessment techniques is an important skill that every trainer must develop. As a trainer, you must have a clear understanding of how to recognize the nature of each assessment, when each assessment should be utilized, and how to perform a safe and effective assessment. Client goals and specific needs will often determine which test is most appropriate and it is your responsibility to recognize proper timing and assessment choice.

Muscular strength testing is an important aspect of the muscular fitness assessment. The absolute strength of a muscle is defined as the greatest amount of weight that can be lifted at one time. In sports science, this is defined as a one-repetition maximum (1 RM). Many strength tests are performed using free weights, so proper form and control are essential. Keep in mind that novice exercisers may not have the familiarity or skill to handle heavier free weights. Therefore, because the safety and well being of the client is of the utmost importance, it’s critical that you know when to use actual 1 RM vs. predicted 1 RM muscular-strength assessment techniques. And, as there is no single test that evaluates total-body muscular strength, multiple tests are often necessary. Bench press, leg press and squat should be incorporated into a comprehensive session to evaluate total-body muscular strength. Regardless of which assessment is used, a proper warm-up is always necessary to help avoid injury and improve performance.


Predicted 1 RM AssessmentOne-repetition Maximum

Submaximal strength testing is a great way to estimate 1 RM performance in a novice exerciser who has inadequate experience handling free weights. Table 8-32 (from the ACE Personal Trainer Manual), below, can help you determine a client’s predicted 1 RM. For example, while your client performs bench presses, you observe that the client consistently completes eight repetitions with 160 pounds. Using the coefficient 1.255, the client’s 1 RM is calculated as follows:

1 RM = 160 pounds x 1.255 = 201 pounds


Actual 1 RM Assessment

1 RM-Repetition Table While predicted 1 RM uses submaximal effort levels, actual 1 RM will push the client to his or her limit. Because of this highly strenuous activity, the client must have the ability to perform the exercise with proper technique and skill. The client should warm up and begin with light resistance (50% of anticipated 1 RM weight), not exceeding 10 repetitions, and then rest for one minute. The second set should increase the amount of weight (70-75% of the anticipated 1RM weight) and decrease the number of repetitions (three to five), allowing one minute for rest. The third set should be performed at 85 to 90% of the anticipated 1 RM for two to three repetitions, followed by a two- to four-minute rest. The information gained from the third set is then used to determine the workload for the client’s 1-RM effort. Table 8-27 can be used to calculate and determine an appropriate weight for the client’s 1 RM.

If your client performs eight repetitions at 150 pounds, this represents roughly 80% of his or her 1 RM. To calculate the 1 RM trial, take the weight of the third set (150 pounds) divided by the % of 1 RM as determined by Table 8-27 (80% or .80) to get a 1-RM trial weight of 187 pounds (150lbs/.80= 187lbs). If a successful 1 RM is performed, allow the client to rest for two to four minutes before attempting the 1 RM effort with a slight increase of roughly 5 to 10 pounds. If the 1 RM is unsuccessful, allow the client to rest for two to four minutes before attempting the 1-RM effort with a slight decrease of roughly 5 to 10 pounds. This procedure should be repeated until the client achieves their 1 RM, ideally in no more than five total sets.

Improvements in 1 RM can be very motivating for clients who wish to increase their muscular strength. Keeping records of 1 RM is a valuable tool for future evaluation of these clients. Always remember that 1-RM strength assessment is not for every client and it is your responsibility to use proper assessment techniques based on the client’s individual needs and goals.