What does RIR mean?

RIR stands for “repetitions in reserve.” It expresses how many reps you have left in the tank when stopping any given set. This means that if you pick a weight that you can do for a set of 10 reps ALL OUT, an RIR of 3 would mean you would likely hit 7 reps on your first set under ideal conditions. It is important to note that in your next set, you are unlikely to repeat the same number of reps as fatigue will influence your ability to perform. So it is possible that so long as you are holding firm on the 3RIR on your second set, after rest, you may only hit 5 reps or 6 reps. Some people will have a greater drop off in performance set over set and some will have less. So long as you are doing your best to hold to the RIR, you will see progress!