REPETITIONS IN RESERVE (RIR)

RIR is a tool used to describe how challenging an exercise set was by estimating how many reps you believe were left before reaching absolute fatigue.
E.g. 10 BB back squats - 2RIR would represent a weight you can only do 2 more reps with.

0RIR - maximal effort
1RIR - 1 repetition left
2RIR- 2 repetitions left
3RIR - 3 repetitions left
4-6RIR - moderate effort
6-8RIR - light effort
8-10RIR - no effort