Pull-up vs chin-up: in the Zyra Workouts catalog they are the same exercise with a different grip — both are back-primary compound movements with the biceps, forearms and core as secondaries, both rest 150 s, both move your whole bodyweight. This guide explains what the grip changes mechanically, how the app counts a lift where the load is you, and what progression looks like when the load step is zero. The two rows: pull-up and chin-up.
Muscles worked
| Role | Muscle group | Counts per working set |
|---|---|---|
| Primary | Back | 1 set |
| Secondary | Biceps | 0.5 set |
| Secondary | Forearms | 0.5 set |
| Secondary | Core | 0.5 set |
Mechanically both are shoulder extension and adduction (the lats and the rest of the back pull the upper arms down and in) plus elbow flexion (biceps and forearm flexors bend the arm), with the trunk held still against a hanging load (core). The grip changes the elbow's path: palms away and wide, the elbows travel out to the sides; palms toward you and narrow, the elbows travel forward and down, a line the biceps pull along more directly. That is the whole difference the movement makes, and it is a description of leverage, not an electromyography result — the catalog credits biceps identically on both rows.
| Pull-up | Chin-up | |
|---|---|---|
| Grip | palms away (pronated), wider than shoulders | palms toward you (supinated), shoulder-width or narrower |
| Catalog row | back; biceps, forearms, core | back; biceps, forearms, core |
| Category · rest | compound · 150 s | compound · 150 s |
| Bodyweight fraction | 1 | 1 |
| Load step | 0 | 0 |
Setup and execution
- Hang from the bar with straight arms and the shoulder blades let up — the dead hang is the start and the end of every rep.
- Pull the shoulder blades down first, then bend the elbows and bring the chest toward the bar until the chin clears it.
- Lower under control back to straight arms. A rep that stops short of a dead hang at the bottom or short of the bar at the top is a partial, and the app logs partial reps separately from full ones.
- If you add load (a belt, a dumbbell between the feet), log the added weight on the set; leave it at 0 for plain bodyweight.
Rep and RIR targets by goal
Both rows are compound, so they get the compound table.
| Goal | Reps | RIR | Rep ceiling | Sets (beginner / intermediate / advanced) |
|---|---|---|---|---|
| Strength | 3–5 | 2 | 6 | 3 / 4 / 5 |
| Hypertrophy | 6–10 | 2 | 10 | 2 / 3 / 4 |
| General fitness | 8–12 | 2 | 12 | 2 / 3 / 4 |
RIR is reps in reserve — how many more reps were left when the set stopped. @RIR 2 means the set ended two reps short of failure. The rep ceiling is the engine's "expected max": the midpoint of the range plus the RIR target, round((repMin + repMax) / 2) + rir. Beat the ceiling and the load steps up next time.
Bodyweight contribution: what the pill means
Every set has a weight field, and for a bodyweight row that field means *added* load — 0 for a plain set. The catalog also carries a bodyweightFraction per bodyweight exercise: 1 for the pull-up and the chin-up (all of you hangs from the bar), 0.64 for the push-up (part of you rests on the floor). Insights use it to compute a normalized volume for bodyweight work:
normalized load = scale weight × fraction + added load, then × reps.
So for a lifter whose latest weigh-in is 75 kg, a set of 8 unloaded pull-ups is (75 × 1 + 0) × 8 = 600 kg of normalized volume, and the same set with a 10 kg belt is (75 + 10) × 8 = 680 kg. The scale weight comes from your latest body-weight entry, so an unchanged set of pull-ups reads as slightly more or less volume as your weight changes — that is the arithmetic, not a judgement.
The logging design specifies a pill next to the exercise name that shows the same numbers in one line, in the form 165 lb / +28 lb (17%) — scale weight, added load, and the added load as a share of scale weight (28 / 165 = 17%). That pill is coming; today the normalized figure lives in insights, and Zyra Workouts is in development and not yet on the App Store.
Progression when the step is zero
The step rule gives bodyweight exercises a load step of 0, so the engine has only one lever: reps. Its rule then reads:
| Last set (6–10 @RIR 2, ceiling 10) | Next session |
|---|---|
0 kg × 11 — above the ceiling | 0 kg × 10 — progress, shown as the top of the range |
0 kg × 8 — inside the range | hold 0 kg × 8 |
0 kg × 5 — below the floor | 0 kg × 6 — back-off, shown as the floor |
Read the first row carefully: the engine cannot add load, so once you beat the ceiling it simply keeps you at the top of the range. In plain terms: past 10 clean reps the engine has nothing more to give you on that row, and the next move — a belt, a slower tempo, a harder variant — is yours to make. Adding load turns the set into a weighted one (weight field > 0), and the reps rule keeps working on top of it. The lat pulldown, which has a 2 kg step, is the catalog's loadable stand-in when you want the engine to drive the load.
How progression steps on this exercise
Covered above: step 0, reps only, clamped at the top of the range. No 1RM page exists for either row because there is no external load to estimate from.
Alternatives
Ranked for the pull-up (same primary muscle — back — then +4 loadable, +2 same category, +1 same equipment, then name):
| Rank | Alternative | Score |
|---|---|---|
| 1 | Chin-up | compound, bodyweight — 7 |
| 2 | Barbell bent-over row | compound, barbell — 6 |
| 3 | Conventional deadlift | compound, barbell — 6 (back-primary in the catalog) |
| 4 | Lat pulldown | compound, cable — 6 |
For the chin-up the list is the same with the pull-up in first place. The deadlift at rank 3 is honest about the catalog: it is filed as back-primary, so the substitution rule counts it as a back swap even though it is a very different lift.
The short version
Same catalog row, different grip: back first; biceps, forearms and core at 0.5 each; 150 s rest. Bodyweight counts as scale weight × 1 plus whatever you add. The load step is zero, so the engine moves reps and stops at the top of the range — beyond that, adding load is your call. Zyra Workouts is a training log, and this page is a guide to one movement in its catalog. Educational overview only — not medical advice.