What’s My 1-Rep Max?

What’s My 1-Rep Max?

Written by Calvin Sun

Knowing your 1-Rep Max is an important part of making the most of the programming provided by your coaches at Invictus. Our coaches frequently use percentage references in prescribing the number of reps to perform, so it’s essential that you have a good idea on most of your maxes. “Work up to 85% percent of your max for a single” is pretty useless if you don’t have a good idea of what you can lift.

1-Rep Max Formula

Let’s say it’s been awhile since you have attempted a 1RM; maybe you had an injury a few months ago, or maybe you just somehow keep missing the 1-RM test days, or maybe you just forgot to write it down in your log book. If you have a multiple-rep max, you’re in luck. There’s a actually a simple equation you can use to calculate an estimated 1RM based on the max number of reps you can do at a given weight. Here’s the equation:

1RM = 0.0333 * Weight * Reps + Weight

Formula Limitations

In my experience, there are a few limitations with this formula. It seems to work best with rep-maxes in the 3 to 10 range. For example, I recently deadlifted 455 for 6. Based on the formula (.0333*455*6+455), my estimated 1RM is 545. I’ve also deadlifted 425 for 12, again based on formula (.0333*425*12+425) my max would be 595. My actual 1RM is around 540 so for me, the lower rep range tends to be a more accurate. I’ve found the same to be true with most of the athletes I have coached over the past few years. Another limitation with this formula is that it tends to work better with intermediate and advanced athletes. Beginners tend to have trouble working up to a true 1RM. Most beginners and some intermediate level athletes will have trouble producing a true 1RM; they’ll get under the bar and get scared, their technique starts to breakdown, a mobility issue prevents them from moving correctly, poor body awareness results in poor range of motion, etc…They also have trouble working up to a multiple-rep max for the same reasons.

Keep in mind, the aforementioned equation is just a tool to help you estimate your 1RM for training purposes. I wouldn’t use it to project attempts for a competition and I definitely wouldn’t obsess over your projected 1RMs either. But it’s a useful tool because we don’t want to test our 1RM too frequently. There are more than a few problems with training 1-Rep maxes with high frequency. One problem is that 1RMs are very taxing on the body in terms of neurological and muscular physiology. Too much volume and intensity can slow recovery and even lead to overtraining depending on the athlete. Keep it simple. Just be consistent and train smart and you will continue to make gains in your lifts.

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