Strength Training PR Calculator

The core function of the strength training PR calculator is to estimate your maximum weight for one repetition (also known as 1RM PR) based on the maximum weight you can perform for multiple repetitions without exhaustion using standard movements (such as a bench press weight that can be done steadily for 3 times). It can also match the reference weight corresponding to different training goals, so you can find your own strength ceiling reference value without risking injury when pushing heavy weights.

When I first started practicing strength, I was always holding back my energy to push heavy weights to prove myself. The last time I bench pressed 110kg blindly, I didn't find anyone to protect me. I sprained my shoulder for half a month. Later, after I found out about this thing, I saved a lot of effort blindly testing weights, and rarely took the risk of injury for testing PR.

The most commonly used formula in the fitness circle is the Epley formula. The calculation logic is "test weight × (1 + test times/30)". For ordinary fitness enthusiasts, the error is the smallest, especially if the number of times you measure is between 3-10 times, the difference is basically 2.5kg. Last month, I deadlifted 80kg for 5 standard movements steadily. Using this formula, I calculated that my 1RM was about 93kg. Later, I asked a friend to protect me for PR, and I steadily pulled up 92.5kg, which was ridiculously accurate. There is also the Brzycki formula, the logic is "test weight × (36/(37-test times))". This is more suitable for low-rep estimation. For example, the weight you measure can only be done 1-3 times. The results calculated using this will be closer to the actual level than Epley. If you are a powerlifter and are used to lifting heavy weights, then the Lombardi formula may be more suitable for you. The calculation logic is "test weight × test times ^0.10". Many powerlifters will refer to the results of this formula when choosing the starting weight.

Of course, this thing is not a golden rule, there are individual differences. My brother who practices CrossFit has been through a trap. He can bench press 60kg 12 times in a row. According to the formula, his 1RM can reach 84kg. When he actually sprints, he is stuck at 80kg - his endurance talent points are full, and the neural recruitment ability corresponding to absolute strength cannot keep up. In this case, the reference value of the calculator will be compromised. Oh, by the way, don’t use force-borrowing movements to calculate. Last time, a little brother calculated the weight of the bench press by kicking off the bridge and bending the back into a bow. The result was that the 1RM was higher than mine. In fact, when pressing with standard movements, it took even half of my weight. This is pure self-deception. When measuring, you should also choose the weight of the formal set. Don't count the last half of the trembling failure set. Allow at least 3 minutes of rest between sets. Don't test with fatigue, otherwise the results will definitely be inaccurate.

It is also convenient to use during daily training. For example, if you are looking for a weight of 8-12RM to gain muscle recently, just calculate the 1RM and multiply it by 0.7-0.8. There is no need to waste energy by squatting on the rack and repeatedly adding weights every time. If you are preparing for strength training in a competition, you should look for a weight of 4-6RM, multiply it by 0.85-0.9 and it will be about the same. Just add weights at this weight during warm-up, which is much more efficient.

Of course, there are many people who think this thing is completely useless. I know a veteran who has practiced powerlifting for 8 years and never uses it. He said that everyone's neural recruitment ability is too different. Some people usually train with sub-heavy weights. When the adrenaline comes up when they really sprint for 1RM, they can be more than 10% more than what the calculator calculates. If you really want to measure PR, you still have to actually sprint. The calculator is at best a reference for calculating weight during warm-up. There's nothing wrong with that. After all, tools always serve people. You can't rush with the numbers calculated by the calculator. If you still hold on to something when it's clear that it can't be pushed, that's just making trouble for yourself.

Especially those who have just started training can really try it. Don’t just rush to 1RM blindly. Use a calculator to make a rough calculation first. During the warm-up, slowly increase it. If you feel it is stable, then rush again. If it doesn’t work, it doesn’t matter if it is 2.5kg short. The most feared thing about strength training is injury. The time to recover from injury is enough for you to gain several PRs.