A bar with a palms-up grip gives the biceps more than a neutral hold does. A rope lets the wrists rotate freely and suits elbows that dislike a fixed grip. Pick one and stay with it inside a block.

Arm isolation · Machines and cables

Cable curl

A low pulley, a straight or angled bar, and tension that never goes away. A dumbbell gets easy at the top of the rep because gravity stops fighting you. A cable does not, which is the entire argument for it.

Elbows pinned, control the way down.

The cue Reckoner puts on your wrist mid set.

Pattern: Arm isolation
Trains: Biceps
Kit: Cable
Loading: A weight you choose
Reckoner prescribes: 3 sets of 10 to 15 reps at RPE 8
Progression step: 2.5 kg once the top of the range is clean
Skill: Simple to learn
Recovery cost: Very low
Not prescribed if you have declared: Elbow

Muscles worked

Primary

Biceps

Secondary

Forearms

How to do it

Set the pulley at the bottom
Attach a straight bar, an angled bar or a rope. Take the handle and step back a pace, so the cable already has tension on it with your arms hanging.
Stand tall, elbows at your sides
Feet hip width, chest up, elbows tucked against your ribs. Elbows pinned, control the way down, which is the cue on your wrist.
Curl up to just past vertical
Squeeze at the top and hold for a beat. With a palms-up grip on the bar you get the most out of the biceps: it produced higher excitation than neutral or palms-down grips at the same load¹.
Resist the whole way back down
The lowering half is where a cable earns its money, because the stack is pulling the whole time. Take longer over it than the way up and finish with straight arms.

What goes wrong

Standing right on top of the pulley
Too close and the cable goes slack at the bottom, which throws away the constant tension you came for. Take one step back so the line stays loaded from the first inch.
Leaning back to finish
The cable pulls you forward, so leaning away from it counterweights the load and quietly finishes the rep for you. Ribs down, feet planted, and if you cannot stay upright take the pin up one.
Only ever doing the top half
The squeeze at the top feels like the exercise and the stretch at the bottom does most of the work. Pooled comparisons favor the full range on every outcome².

How Reckoner progresses this lift

Six weeks of this lift, from 20 kg, run through the real engine. Nothing below was typed in: the prescription, the decision and the sentence beside it all come from the same code that writes your week.

Cable curl, six weeks
Week	Prescribed	What it did
1	3 x 10 at 20 kg	More reps 10 → 11 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does.
2	3 x 11 at 20 kg	More reps 11 → 12 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does.
3	3 x 12 at 20 kg	More reps 12 → 13 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does.
4	3 x 13 at 20 kg	More reps 13 → 14 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does.
5	3 x 14 at 20 kg	Deload 40% of sets offFive weeks of building, then one week lighter. About 40% of the sets come off. The load holds and your reps stay where you earned them, so you keep the strength and lose the fatigue.
6	2 x 14 at 20 kg	More reps 14 → 15 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. The lighter week is over, so this is back to three sets.

Real engine output, not an illustration. Every row was produced by running the engine itself when this page was generated.

The full rule, and why the reps move before the load does, is in how Reckoner decides to add weight.

Questions people ask

Is a cable curl better than a dumbbell curl?

It is different. A cable holds tension across the whole range including the top, where a dumbbell goes light. Nobody has run the comparison for growth, so treat it as another way to curl rather than an upgrade.

Rope or bar?

A bar with a palms-up grip gives the biceps more than a neutral hold does¹. A rope lets the wrists rotate freely and suits elbows that dislike a fixed grip. Pick one and stay with it inside a block.

Why does the step on this move in smaller amounts than the row beside it?

Different columns on a cable stack move the weight at different ratios, and the library records the real step for each machine. The fact block above carries it for this movement.

Similar movements

Reckoner eases the load first when this lift stalls, and offers one of these only if it stalls again after that. A lift already as light as your kit goes has no load left to ease, so the offer comes straight away. Each of them has a page.

Barbell curl Concentration curl Dumbbell biceps curl Dumbbell hammer curl EZ bar curl EZ bar preacher curl Inverted curl

Sources

Coratella and colleagues, Sports, 2023. Biceps brachii and brachioradialis excitation in biceps curl exercise: different handgrips, different synergy ten competitive male bodybuilders curling a cable at an eight repetition maximum with supinated, neutral and pronated grips, with biceps brachii excitation in the lifting phase greater with the supinated grip than the neutral by twelve per cent and than the pronated by nineteen, and brachioradialis excitation also greater with the supinated grip than either of the others, and no significant grip differences in the lowering phase
Wolf and colleagues, International Journal of Strength and Conditioning, 2023. Partial vs full range of motion resistance training: a systematic review and meta-analysis a meta-analysis reporting a trivial standardized mean difference of 0.12 in favor of full range training, with every outcome favoring full range but all effects between trivial and small, and a subgroup suggesting partials held at long muscle lengths may match or beat full range for size

Muscles worked

How to do it

Set the pulley at the bottom

Stand tall, elbows at your sides

Curl up to just past vertical

Resist the whole way back down