Plateaus

Why your biceps deserve more patience than your squat

Three bench sessions in a row with no improvement is worth looking into. Three curl sessions in a row with no improvement is a completely ordinary fortnight of training arms.

Most trackers treat those identically, and that produces one of two failures. Either the threshold is set for the squat, in which case your arms are permanently flagged as stalled. Or it is set for the curl, in which case a genuine squat plateau goes unmentioned for a month.

The fix is not clever. Small muscles get roughly double the patience before anyone calls a stall.

Why the smallest available jump is the whole story

This is arithmetic rather than physiology, which is what makes it convincing.

Say you squat 140 kg. The smallest increase you can realistically make is 2.5 kg, and often 5. That is under two percent of your working weight. A month of decent training can produce several jumps that size, so progress shows up regularly and a run of flat sessions genuinely is unusual.

Now say you curl 25 kg. The smallest jump available is the same 2.5 kg, and now it is ten percent. Ten percent on any lift is a serious increase. You are not adding that every couple of weeks, and you should not expect to.

So the curl spends far longer sitting at one weight, accumulating flat sessions, while you slowly build the capacity to make a jump that is five times larger in relative terms than the one the squat needs. Those flat sessions are not a stall. They are what the waiting looks like.

Reps in reserve soften this but do not remove it. You can improve at a fixed weight by getting the same reps more easily, and that shows up as progress. But the load itself still moves in chunky steps, and the smaller the muscle, the chunkier they are relative to what it lifts.

The classification

Small, and therefore given double patience: biceps, triceps, side delts, calves, brachioradialis, forearm flexors.

Large, on the standard allowance: everything else. Upper chest, lower chest, lats, upper back, erectors, quads, hamstrings, glutes, adductors, abs, front delts, rear delts, upper traps, lower traps, neck.

Combined with experience level, that produces the actual thresholds. A beginner gets two consecutive sessions without progress on a large muscle before it counts as a stall, and four on a small one. An intermediate gets three and six. Advanced, five and ten. Elite, seven and fourteen.

An intermediate lifter with three flat bench sessions has a stall worth diagnosing. The same lifter with three flat curl sessions is halfway to the threshold and should keep training.

The classification has a genuinely awkward edge

Worth stating plainly rather than glossing: rear delts are on the large list. So are abs, adductors, upper traps, lower traps and neck.

If you train rear delts with face pulls and reverse flyes at 8 kg, calling that a large muscle group with the same patience as a squat feels wrong, and by the logic in the first half of this page it arguably is wrong. The smallest available jump on a reverse flye is an enormous percentage of the load.

The reason they sit where they do is historical. The classification was originally written around movement patterns rather than muscles, and the movements that trained rear delts, traps and abs were big compound pulls and presses. When it was translated to a muscle-by-muscle list, the translation was done strictly, without quietly adding the muscles that obviously should have moved.

That was a deliberate choice: a strict translation preserves exactly what was agreed, whereas a helpful one changes a decision under cover of tidying it up. The cost is a list with a visible seam in it, and this is the seam. It is flagged rather than smoothed over, because a rule you can see the awkwardness in is easier to trust than one that has been quietly improved.

In practice, if your rear delts show a stall at three sessions, apply some judgement.

What is not on either list

The rotator cuff is deliberately untracked. External rotation work counts toward no muscle group's volume and resets no clock.

This is not an oversight and it is not a claim that the work is pointless. It is a decision that the app has nothing useful to say about it, and the honest way to express that is to show it as unclassified rather than to file it under shoulders and let it quietly inflate a number.

An unclassified row you can see is better than a wrong number you cannot.

What to do with this

Mostly, stop worrying about arm progress on a two-week timescale. A run of flat curl sessions that would be alarming on a squat is the normal texture of training a small muscle, and the most common response to it, which is adding more arm volume, tends to make things worse rather than better.

The other use is diagnostic. If a small muscle group does cross its doubled threshold, that is a considerably stronger signal than a large one crossing its own, because it survived twice the noise. Six flat sessions of biceps for an intermediate lifter is worth taking more seriously than three flat sessions of bench.

Common questions

Which muscles count as small for training purposes?

Biceps, triceps, side delts, calves, brachioradialis and forearm flexors. Everything else is treated as large, including some that feel small, such as rear delts and abs.

Why do small muscles get twice as many sessions before a stall is called?

Because the smallest weight jump available is a much larger percentage of their working load. A 2.5 kg increase on a curl can be a ten percent jump, and flat sessions are the normal shape of waiting to earn one.

Are rear delts really treated as a large muscle group?

Yes, and it is the least intuitive part of the classification. They are grouped with the large muscles, which means they get the same patience as a squat rather than the doubled allowance a bicep gets.

Does this mean I should train small muscles differently?

Not necessarily. It changes how quickly a run of flat sessions should worry you, not how you should train. The main practical effect is not panicking about arm progress on a normal timescale.

What about rotator cuff work?

It is deliberately not tracked at all. External rotation work does not count toward any muscle group's volume and does not reset any training clock, and it is shown as unclassified rather than being quietly filed somewhere.