Sit on a bench with your back straight and hold a weight (dumbbell or plate) with both hands. Lift it overhead until your arms are fully extended. Keep your elbows close to your head and slowly bend them to lower the weight behind your head in a controlled motion. Pause briefly at the bottom, then extend your arms back up to the starting position by contracting your triceps. Keep your core engaged and avoid arching your back or flaring your elbows.
Log your weighted seated triceps extension sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.