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How to test your one rep max safely

The one rep max is the ultimate strength test, but how do you find out your one rep max? And what is the safest way to test your one rep max?

Musculoskeletal fitness is commonly evaluated through the static (without movement) or dynamic (with movement) assessment of muscular strength and muscular endurance. Because muscular strength is an indicator of force production and contributes to power output (along with speed or velocity), it plays a large direct or indirect role in many activities of daily living, recreational endeavours and sports performance. Furthermore, higher levels of muscular strength may provide a protective effect with respect to injury. Maximal dynamic strength can be safely measured using a one rep max test in resistance-trained individuals.

Adapted from our new book, Assessments for Sport and Athletic Performance this article provides assessments for a one rep max test on back squat.

Find your one rep max safely


The one-repetition maximum (1RM) strength test measures the maximal strength of the muscle groups engaged during a single specified movement.


Maximum amount of weight lifted for a single repetition (termed absolute strength); maximum strength relative to body weight (termed relative strength).

Equipment Needed

Rack or stands; barbell; safety locks; weight plates; spotters

Before You Begin

Review the basic elements of the movement to be assessed (preferably during a familiarisation session prior to testing) with the client or athlete and spotters. These selections should be made with consideration for the muscle groups used.

Clear the lifting area, place the supports at the appropriate height in order to hold the barbell at an easily accessible location for the client or athlete. Lower the safety bars enough to allow for the full range of motion and make sure that the collars are in working order. Verify that the selected spotters are of adequate size and strength to support the loads lifted by the client or athlete being evaluated.

Prior to attempting the 1RM test, determine a phrase (such as “take it”) or an action that will signal that the client or athlete cannot complete a repetition. Upon hearing or seeing this signal, the spotters should jump in and assist with reracking it on the supports.

A standardised general warm-up followed by three to five minutes of rest and recovery should be conducted prior to beginning the assessment. A specific lifting warm-up is built into the 1RM protocol.

Back Squat Technique

Starting position (barbell on the rack)

one rep max safely


  • With the feet parallel, position the barbell across the shoulders or back and grip with the hands (with the palms forward and the thumbs wrapped underneath) a comfortable distance outside of the shoulders.
  • Bring the elbows under the barbell with the chest up and the eyes forward before lifting it from the rack supports and taking a step or two backwards.
  • Reposition the feet to shoulder-width apart or wider and point the toes slightly outward.


  • Stand at each end of the barbell and grip with both hands (with the thumbs crossed below).
  • Coordinate with the client or athlete to assist with the liftoff of the barbell and release the hands but keep them in close proximity.

Downward movement

one rep max safely


  • Keep the back straight, chest up, eyes forward and elbows down; maintain the grip on the barbell.
  • Slowly bend the knees and hips (similar to sitting in a chair) and lower the barbell in a smooth, controlled motion; maintain the heels on the floor and the knees over the feet.
  • Continue the descent until the thighs are parallel with the ground, the back begins to bend excessively or the heels begin to rise from the floor.


  • Without touching the barbell, mirror its downward movement using both hands (with the thumbs crossed below).
  • Keep the back straight while bending the knees and hips through the descent of the barbell.

Upward movement

one rep max safely


  • Keep the back straight, chest up, eyes forward and elbows down; maintain the grip on the barbell
  • Simultaneously extend the knees and hips and raise the barbell in a smooth, controlled motion until reaching the starting position.


  • Without touching the barbell, mirror its upward movement using both hands (with the thumbs crossed below).
  • Keep the back straight while extending the knees and hips through the ascent of the barbell.



  • Following completion of the intended number of repetitions and returning to the starting position, step forward and position the barbell back on the supports.
  • Slightly bend the knees and lower the shoulders from under the racked barbell.


  • Grip the barbell with both hands to assist with placing the barbell back on the supports.


  1. Begin the procedure by saying something like: “We are going to measure your strength during a single specific lifting movement. Are you ready to begin? If so, please get into the starting positon.”
    to the client or athlete
  2. Make sure to account for the weight of the unloaded barbell or sled and add a minimal amount of weight for the initial warm-up set.
  3. Next, direct the client or athlete: “Start with a warm-up set of 5 to 10 repetitions and focus on using proper technique. After the first warm-up set, you will rest for one minute.”
  4. After one minute of rest add an additional 30 to 40 pounds (14 to 18 kg) for back squat or leg press. 5 to 9 kg for bench press or bench pull.
  5. Continue by saying: “Now complete another warm-up set of two to three repetitions with proper technique and then rest for a few minutes.”
  6. After two to four minutes of rest add more weight, another 30 to 40 pounds (14 to 18 kg) for back squat.
  7. Tell the client or athlete: “Now attempt to complete one repetition with proper technique. After your attempt, you will rest for a few minutes. Depending on your performance, we will add or remove some weight and try again.”
  8. After two to four minutes of rest: If the previous back squat attempt was successful, add an additional 30 to 40 pounds (14 to 18 kg).
  9. If the previous back squat attempt was unsuccessful, remove 15 to 20 pounds (7 to 9 kg).
  10. Continue attempts (repeat from step 7) until a 1RM value can be identified, preferably within three to five sets so fatigue doesn’t set in. Note: The load increases during 1RM testing can be larger for more experienced or stronger clients or athletes and potentially lower for those with less experience or baseline strength.

Alternatives or Modifications

If the client, athlete, coach or the fitness professional is relatively new to weight training or a particular movement pattern, the multiple-repetition maximum strength test protocol outlined in Assessments for Sport and Athletic Performance may be more appropriate.

The estimated percentage of 1RM for a given number of repetitions is provided in Assessments for Sport and Athletic Performance. For example, the client or athlete would be able to complete approximately three repetitions at roughly 93% of the 1RM, or 5 to 10 repetitions between 75% and 87% of the 1RM. Note that these estimated values do not consider specific muscle groups and will likely vary depending on the use of the upper versus lower body.

After You Finish

The greatest amount of weight lifted with good technique for a single repetition is the final result. In an effort to account for the size differences between clients or athletes, relative strength can be calculated by dividing the RM test result by body weight. This is explained further in Assessments for Sport and Athletic Performance.

Research Notes

Considerations for body weight are relevant to the evaluation of maximal strength. For example, heavyweight powerlifters clearly dominate when examining absolute strength, whereas lightweight powerlifters possess greater relative strength. Which begs the question: Who is the strongest?

Absolute strength is highly related to body weight, with larger individuals demonstrating greater strength values; however, a similar relationship exists between relative strength and body weight but in the opposite direction, with smaller individuals potentially demonstrating greater strength values.

Ultimately, the actual application of strength and potentially the influence of power during a particular sport or activity will play a role in which approach is most valuable to the coach or fitness professional.

Relative strength may be of particular importance in situations where a client or athlete is losing or gaining body weight to determine the influence of these changes on performance.

From a sports medicine perspective, weaker youth female athletes have approximately 9.5 times greater odds of traumatic knee injury than stronger female athletes as determined by 1RM back squat, while a similar increase in risk was not found for youth male athletes. The researchers who conducted this investigation reported a 1RM back squat cutoff of less than 105% of body weight for high versus low risk of injury in youth female athletes.

Normative Data

One rep max strength classification values for male high school and collegiate athletes are provided in Assessments for Sport and Athletic Performance. One example shown is for the back squat of College American Football players. High school players aged 14-15 averaged around 130kg, 16-18-year-olds averaged 150kg, Division 3 players averaged 170kg and Division 1 players typically averaged 180kg. Female college athletes vary a lot depending on their sport, for example, female volleyball players typically average 65kg for one rep max back squat, swimmers average 57kg.

According to Strength Level, the average 80kg male lifter should be able to squat 129kg and the average 70kg female lifter should be able to squat 76kg for one rep.

Live case study

I’m currently taking part in a Linear Periodised Programme for Loading, taken from Brad Schoenfeld’s book Science and Development of Muscle Hypertrophy. I have a goal of improving my squat 1RM along with my deadlift, strict press and bench press.

Find out how I’m getting on with it here.

Header photo by Ketut Subiyanto from Pexels

This entry was posted in: Fitness & Health


Hi, I'm Ryan, the Marketing Manager and chief blogger here at Human Kinetics Europe Ltd. As somewhat of a washed-up athlete I've always had a passion for health, fitness and sport science. I now find myself working at the world’s biggest independent publisher of sport, health, dance and fitness resources. This means I get unrestricted access to all the best, most interesting, scientifically-proven writing on sports science. Of course I'm going to share this with you!

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