Lie flat on a bench holding an EZ bar with a close, overhand grip. Extend your arms so the bar is above your chest. Keeping your upper arms mostly stationary and elbows tucked in, slowly bend your elbows to lower the bar in an arc behind your head. Lower until you feel a deep stretch in your triceps, then extend your arms to bring the bar back to the starting position.
Log your ez bar lying close grip triceps extension behind head sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.