Stand facing a cable machine with an SZ (cambered) bar attached to the low pulley. Grasp the bar with an underhand grip about shoulder‑width apart. Keeping your elbows close to your sides and your torso still, curl the bar upward by bending at the elbows and squeezing your biceps at the top of the movement. Slowly lower the bar back to the starting position with control, maintaining tension through the cable throughout.
Log your cable biceps curl (sz bar) sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.