Biceps curl with twist seated on a stability ball

Flex the elbow without letting the shoulder drift forward or the torso swing. Lower the load under control until the starting position is restored. Prioritize control over speed. Maintain useful tension through the range and deliberately reset the starting position before the next repetition.

Do not turn the final repetitions into fast or partial movements. Aim to load biceps, forearms and lower back without sacrificing position; at beginner level, progress control first and then add load, repetitions or complexity. On unstable surfaces, master the position with light resistance first; stability should limit difficulty before load does.