Cable 21s

Biceps Tier C for Biceps Cable Isolation Pull

Try it now

3sets

21reps

90srest

~4.9kcal/min

BicepsC Biceps Brachialis

Forearms

Secondary muscles help but are not the main target

Where you should feel it, the one cue to remember, and quick fixes when you feel it somewhere else.

You should feel it inFront of arms

Front of the upper arm pumping up.

Key cue (the coach says it during the set)“Elbows pinned, curl up, squeeze, lower slowly.”

Tempo · Up 1 s · squeeze 1 · down 3 s

Choosing the load: Pick a weight you finish with 1–2 good reps left. 4+ left = too light; form breaks = too heavy.

Feel it in ShouldersElbows drifting forward and the shoulders lifting. Keep the elbows at your sides and lighten the weight.
Feel it in Forearms / gripWrists curling in. Keep the wrists straight and loosen the grip slightly.
Feel it in Lower backSwinging the torso. Stand against a wall or sit, and use a weight you can lift without momentum.
Barely felt itToo light or too fast. Lower for 3 seconds, pause 1 second at the stretch, and pick a load that leaves only 1–2 reps in the tank.
Joint painSharp or joint pain is a stop sign: end this set, lower the weight, shorten the range — if it repeats, switch to an easier variation.

During a workout we ask after the first set where you felt it and give the fix right away — and remember it for next time.

Use a straight bar on a low pulley for constant tension through all three phases.
Use about 60–70% of your normal curl weight — the burn builds fast.
Count in groups of seven so you don't lose track.
Use 21s at the end of an arm session as a finisher.
Stand far enough from the stack to keep constant tension on the cable.