Barbell curl, dumbbell curl and hammer curl all work the biceps first with the forearms second — and in the Zyra Workouts catalog so do the preacher curl and the incline dumbbell curl. Five rows, one muscle list, one target table. What differs is mechanical: the grip, where the upper arm sits during the rep, and the equipment, which sets the step and the rest. This guide compares all five: the barbell curl, the dumbbell curl, the hammer curl, the preacher curl and the incline dumbbell curl.
Muscles worked
Every curl is elbow flexion: the biceps and the forearm flexors bend the elbow against a load. The biceps also turn the palm up (supination), which is why grip matters mechanically — palms-up loads that turning action, a neutral grip does not, and a neutral grip shifts more of the bending toward the forearm muscles that only bend. Where the upper arm sits changes the biceps' length at the start of the rep: hanging by the side is the neutral case, behind the body (incline curl) starts it stretched, pinned forward on a pad (preacher curl) starts it shortened. All of this is a description of geometry; the catalog credits the same two groups on all five rows and this page cites no EMG study.
Five curls side by side
| Barbell curl | Dumbbell curl | Hammer curl | Preacher curl | Incline dumbbell curl | |
|---|---|---|---|---|---|
| Equipment | barbell | dumbbell | dumbbell | barbell (on a preacher bench) | dumbbell (on an incline bench) |
| Grip | palms up, fixed width | palms up, arms free | palms facing each other | palms up, upper arms on the pad | palms up, arms hanging behind the body |
| Upper-arm position | by the sides | by the sides | by the sides | pinned forward on the pad | behind the torso |
| Category | isolation | isolation | isolation | isolation | isolation |
| Default rest | 90 s | 60 s | 60 s | 60 s | 60 s |
| Load logged as | bar total | per hand | per hand | bar total | per hand |
| Step | 2.5 kg | 2 kg | 2 kg | 2.5 kg | 2 kg |
| Load-chart buckets | 20–60 kg | 10–40 kg per hand | 10–40 kg per hand | 20–60 kg | 10–40 kg per hand |
The barbell curl is the only curl with a 90 s default rest; the catalog gives every other curl 60 s. The bar total for a curl includes the bar — with a standard 20 kg bar that is the floor of the load chart; many gyms have lighter fixed or EZ bars, and what you log is whatever the bar actually weighs.
Setup and execution
- Barbell curl: stand, shoulder-width palms-up grip, elbows by the sides. Curl until the forearms are just short of vertical, lower under control to straight arms. Keep the elbows in one place; the torso stays still.
- Dumbbell curl: the same with a dumbbell in each hand, both arms together or alternating. Palms up throughout, or start neutral and turn up as you curl.
- Hammer curl: dumbbells held palms facing each other for the whole rep, thumbs on top.
- Preacher curl: upper arms flat on the pad, armpits at its top edge; curl and lower to nearly straight without lifting the arms off the pad.
- Incline dumbbell curl: sit back on a 45–60° bench, arms hanging straight down behind the torso line; curl without bringing the elbows forward.
Rep and RIR targets by goal
All five rows are isolation.
| Goal | Reps | RIR | Rep ceiling | Sets (beginner / intermediate / advanced) |
|---|---|---|---|---|
| Strength | 6–8 | 2 | 9 | 2 / 3 / 3 |
| Hypertrophy | 10–15 | 1 | 14 | 2 / 3 / 3 |
| General fitness | 8–12 | 2 | 12 | 2 / 3 / 3 |
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.
How progression steps on this exercise
Barbell and preacher curls step 2 × 1.25 = 2.5 kg with the default plates and carry the plate-inventory check; the three dumbbell curls step 2 kg per hand and are assumed adjustable. On the hypertrophy target (10–15 @RIR 1, ceiling 14):
| Row | Last set | Next session |
|---|---|---|
| Barbell curl | 30 kg × 15 | 32.5 kg × 10 — progress |
| Barbell curl | 30 kg × 14 | hold 30 kg × 14 — ceiling reached, not beaten |
| Barbell curl | 30 kg × 8 | 27.5 kg × 10 — back-off |
| Hammer curl | 12 kg × 15 | 14 kg × 10 — progress |
In plain terms: a 2 kg step on a 12 kg dumbbell is a 17% jump, and a 2.5 kg step on a 30 kg bar is 8%, so dumbbell curls spend longer collecting reps between weight changes. Arithmetic, not a training claim. The barbell curl 1RM page will estimate a max from any logged set, for whatever that is worth on a curl.
Alternatives
The pool is exactly these five rows — no other exercise in the catalog is biceps-primary — so every curl's swap list is the other four, ordered by the rule (+4 loadable, +2 same category, +1 same equipment, then name):
| Starting row | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| Barbell curl | preacher curl | dumbbell curl | hammer curl | incline dumbbell curl |
| Dumbbell curl | hammer curl | incline dumbbell curl | barbell curl | preacher curl |
| Hammer curl | dumbbell curl | incline dumbbell curl | barbell curl | preacher curl |
| Preacher curl | barbell curl | dumbbell curl | hammer curl | incline dumbbell curl |
| Incline dumbbell curl | dumbbell curl | hammer curl | barbell curl | preacher curl |
Same-equipment picks lead each list. Whatever you swap to, the biceps count and the forearm half-credit are unchanged — the variations exist for the mechanics, not for the tally.
The short version
Five curls, one row shape: biceps first, forearms at 0.5. The grip and the upper-arm position change the mechanics — palms up loads the biceps' turning action, neutral shifts toward the forearm flexors, behind-the-body starts long, on-the-pad starts short — and the equipment sets the step (2.5 kg bar, 2 kg per hand) and the rest (90 s barbell, 60 s otherwise). The count does not care which you choose. Zyra Workouts is a training log, and this page is a guide to one movement in its catalog. Educational overview only — not medical advice.