Glossary
Failure
Failure is the point where you can no longer complete a rep with good form.
Training to absolute failure isn't necessary for muscle growth — stopping 1 to 3 reps short (RIR 1–3) works as well with less fatigue.
Also known as
training to failure, muscular failure
Related terms
RIR
RIR is reps in reserve — how many more reps you could have done before failing.
RPE
RPE is rate of perceived exertion — a 1 to 10 scale of how hard a set felt.
Working set
A working set is a set taken close to failure — usually within 1 to 3 reps of stopping.
Mechanical tension
Mechanical tension is the force a muscle generates against resistance during a lift.