Definition of (RIR)

Definition: 

No scientific definition – based on “how many repetitions are left in the ‘TANK’?”

Relationship with RPE:

RIR is in close relationship with RPE for example:

If you do a bench-press exercise and athlete rates exercise intensity at 8/10 on the RPE scale, thus indicates 2 RIR.

RIR = 10 – RPE

      You can use one or the other.