Biceps curl with TRX underhand grip

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 abdominals, biceps and forearms without sacrificing position; at advanced level, progress control first and then add load, repetitions or complexity.