This biceps curl variation will give you a massive pump

To absolutely blast your biceps, combine dumbbell curls with isometric holds.

Iso holds—holding the dumbbells frozen in a fixed, bent-arm position—will increase the time your muscles are under tension.
That helps “pre-exhaust” your muscles, and will lead to greater strength gains even with lighter weights and fewer reps, says Men’s Health Fitness Director BJ Gaddour, C.S.C.S.

Cycle through Gaddour’s 3-set series of seated “iso-go” curls, and you’ll also set your forearms on fire.
Directions: Perform iso-go bicep curls using an overhand grip.

Rest 1 to 2 minutes.

Repeat using a hammer grip, followed by an underhand grip.