ONE-REP MAX CALCULATOR
You can use an online 1RM calculator or simply use one of the equations below to work out what your 1RM could/should be.
For upper body movements, find the heaviest weight you can lift 4-6 times. This should be done for the full range of exercises you most often use: bench presses, overhead presses, weighted dips, rows and so on.
Then use that number in the following equation: (4.6RM X 1.1307) + 0.6998.
For your lower body, do the same, but with this formula: 4-6RM x 1.09703) + 14.2546.
This will give you your 1RM for any given exercise. Or, as mentioned above, simply use an online calculator to find these numbers.
Alternatively, get yourself warmed up nicely, get a decent spotter in, and work up to a heavy single. This is also your 1RM, or near it enough to make no difference.
But what can you do with this information?
ONE REP MAX: THE USES
First and foremost, this can be used in goal setting. If you find that your 1RM is below average for a lifter of your experience, your goal could be to bring it up to average. If you find that you’re in the 80th percentile, find out what it would take to get you into the 85th: your goal could be to reach this.
Mostly, challenge yourself against yourself. If your bench press 1RM is 150kg on January 1st, make it your New Year’s resolution to hit 180kg by Christmas. Plan your programming accordingly.
Aside from goal setting, knowing your 1RM is important for programming.
Each percentage scale of your 1RM has a different use. These uses are:
50%: Training explosive power
Going at around 50% of your 1RM for fast, explosive sets will improve the pace and speed of the muscles involved. Aim for 5-6 sets of 4-5 reps. Your muscles will learn how to generate power without becoming overly large.
70%: Training endurance
This is the high rep range you want to hit for endurance: it will train your muscles to keep going under moderate, consistent loads. Sets of up to 20 reps will burn calories, train you for endurance and raise your metabolism.
80%: Training for hypertrophy
This is where bodybuilders hang out. The 80% range is tough, but you can get a good few sets and reps out of it with plenty of stress to build muscle.
90%: Training power
This, then, is where powerlifters typically hand out. Moving heavy loads at speed will train you for exerting maximal force. Long rests, few sets and few reps will be in order, here.
95%: Training strength
All lifters need to go here, sometimes, just to prove what they can do and show their bodies what they demand of them. Use a spotter where possible and keep sets to 1-3 reps. Train here for a short while- a few sessions per month, at most- before cycling back down to lighter loads.