4. INCLINE CURL
These are a great way to isolate the biceps as you curl your arms up, while also providing great stretch when your arms are extended.
Lie on an incline bench. Holding a dumbbell in each hand as you would in a normal standing dumbbell curl, extend your arms straight down, so your arms are in a stretched position (A).
Squeezing your biceps, flex your elbows, bringing your forearms up to your biceps (B).
Pause at the top, before lowering your arms slowly to the start position.