You finish a session and NOYU shows 14 sets and 6,240 kg. Another app would have said 18 sets and 7,100 kg for the same hour. Neither is wrong. They disagree about what counts as work, and that disagreement is most of what training volume is about.
What volume is
Volume is how much work you did. The simplest version is a count of sets. The fuller version multiplies weight by repetitions for every set and adds them up, so 100 kg for 8 is 800 kg of volume and a session is the sum of its sets.
Both versions are useful because the body responds to volume. Across the research on muscle growth, more hard sets for a muscle each week tends to produce more growth, up to a point where extra sets add fatigue faster than they add results. Where that point sits varies with the person, the exercise and how close to failure each set goes, so no single weekly number applies to everyone.
Working sets are the unit
Not every set is work in that sense. A warm-up is a rehearsal: lighter, easier, done to prepare for the sets that matter. It is worth doing and worth logging, but it does not drive adaptation the way a hard set does, and a research paper counting sets per muscle would not count it.
That is why NOYU calls the rest working sets and treats them as the unit. When NOYU looks at whether you are progressing on an exercise, it reads working sets and working repetitions only. A week where you warmed up more thoroughly does not read as a week where you did more.
Why the total leaves warm-ups out
The session totals follow the same logic by default. Mark a set as a warm-up and it stays in your history but drops out of the set count and the volume figure. Volume is meant to be the work, and a warm-up is preparation for the work, so counting it flatters the number.
If you would rather see everything you lifted, there is a switch in your strength settings that puts warm-ups back into the totals. Progression and records ignore that switch either way. A warm-up never sets a record and never counts as progress.
Bodyweight is load too, sometimes
A pull-up moves all of you, so NOYU counts your bodyweight as the load, plus any weight you add or minus any assistance. The same goes for chin-ups and dips.
A push-up or a bodyweight squat moves only part of you, and how much depends on your proportions and your form. NOYU does not guess a fraction, because a guessed number is not more true for having decimals. Those exercises count repetitions instead.
Volume across a week
One session's volume is a fact. A week's volume is the thing to watch, because that is the timescale muscle responds on. Three sessions of moderate volume for a muscle usually beat one enormous one, and a week that doubles your usual volume for a muscle is the strength equivalent of a Cardio Load spike: possible, but tissue needs time to catch up.
Volume also only tells you how much. It says nothing about how hard each set was or how good the movement looked. A set stopped three reps short of failure and a set taken to the limit produce the same 800 kg on paper. Volume is the frame, not the picture.
