Set a cable pulley at chest height and attach a single handle. Sit on a stability ball and carefully walk your feet forward until your upper back is supported on the ball. Plant your feet firmly on the floor with knees bent about 90 degrees. Hold the handle in one hand with your elbow bent and positioned near your chest. Brace your core and keep your hips level. Press the cable forward until your arm is fully extended above your chest. Slowly return to the starting position under control. Complete all reps on one side before switching arms.
Log your cable one arm press on exercise ball sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.