Training intensity explained

Training intensity is an overloaded term, so define it before changing a program. In resistance training, intensity often means the load relative to a one-repetition maximum, such as 80% of 1RM. In everyday coaching language, it can also mean how demanding a set feels or how close it ends to failure. A brisk circuit may feel intense because rest is short even when each load is light. These are different variables.

Separate load from effort

Load is the external resistance: 20 kg, a specific dumbbell, or a backpack with known contents. Effort can be described with repetitions in reserve. Two sets may use the same 20 kg but end at different effort levels: eight reps at 4 RIR and eight reps at 1 RIR are not identical experiences. The difference may come from rest, accumulated fatigue, range, or the person’s estimate.

Exercise difficulty is another factor. A floor push-up can be more difficult than a wall push-up even though neither has a labeled external load. Tempo and range can also change the task. Avoid writing only “high intensity” in a log. State the thing that changed: 22 kg instead of 20 kg, a lower push-up surface, a shorter rest, or 1 RIR rather than 3 RIR.

Example: three different changes

Session one is a backpack row: 10 kg, 3 x 10, about 3 RIR, 90 seconds rest. Session two keeps 10 kg and 3 x 10 but ends the last set at about 1 RIR. Load stayed the same; effort changed. Session three uses 11 kg for 3 x 8 at about 3 RIR. Load increased, while the rep count reset. Session four uses 10 kg for 3 x 10 with 60 seconds rest. The work prescription has the same load and reps, but the session density changed.

These entries should not be described with one vague intensity score. They are separate decisions. When comparing progress, compare the entire line. A heavier load for fewer reps may be planned progress. A similar load with unexpectedly lower RIR may simply show a different day or rest pattern.

Choose an intensity measure you can repeat

Percentage of 1RM can be useful when you have a tested maximum and a stable exercise. RIR can be useful when you need an effort estimate within a rep range. The 2022 RIR study examined its reliability for specific bench press and deadlift prescriptions, but individual estimates remain context dependent. Do not borrow a percentage-to-rep conversion as if it were exact for every exercise.

The ACSM 2026 resistance-training update distinguishes goals and prescription variables, including heavier loading for strength-oriented work. It does not mean every session needs the same load or effort. Use a measure that answers the decision in front of you: whether to add weight, repeat a variation, or leave more repetitions in reserve.

In your log, make intensity concrete. Record load, reps, rest, and RIR when relevant. Then change one variable at a time. Clear terms prevent the common mistake of increasing weight, shortening rest, and adding reps simultaneously while calling the result a simple intensity increase.