There are multitudes of ways to establish a maximum weight for any exercise, but to ensure safety and longevity it’s important to “earn your reps” by developing good technique. This can be done and locked in through consistent practice.
Approximately two months ago we started back squatting single sets of 20 reps every Monday, slowly adding weight each week until now. At the beginning we started at 60% of our 1-rep maxes (1RM) increasing by 5% or so each week. Last week should’ve been 1 set of 20 reps at 85%. If you were successful we know that your actual maximum is way heavier now. If you weren’t, no problem- no one should be able to 20-rep an 85% and the data collected from that day could be useful for maxing.
Apologies beforehand for making this some math exercise.
Take your results from previous weeks. Use about three previous days of data and plug it into this formula:
ESTIMATED 1-REP MAX = (weight used x reps completed x 0.033) + weight used
Let’s say three weeks ago someone did 80kg for 20 reps, the next week 88kg for 20, then last week was 95kg but failed at 14 reps. This athlete started the 20-rep program with a 1RM at 124kg established more than a year ago.
a. (80*20*0.033)+80=~133kg est 1RM from three weeks ago
b. (88*20*0.033)+88=146kg est 1RM from two weeks ago
c. (95*14*0.033)+95=~139kg est 1RM from last week
With that average this athlete has 139kg as an estimated 1RM. They could then apply that to a simple warmup ladder (percentage/reps):
50/5+, 65/5+, 75/3+, 80/3, 85/2+, 90/1+, 95/1, 98/1 or 101/1
Their plan would be:
70kg for 5 or more reps
136/1 or 140/1+ if confident af!
If the plan isn’t successful then maybe it’s not your day- didn’t sleep well, stressed out, muscles are tight and under-recovered. There are so many variables in fitness other than just executing the exercise.
On the other hand, if it’s your day and the plan is a success the athlete has set multiple Personal Record (PR): 1RM, and more if they can keep going so we don’t spend more time doing singles. Could be a 3RM or even a 7RM!
Now cook up your plans, not just for the back squat but deadlift too!