I usually do tricep extensions with a plate but there weren’t any plates available at the gym this time so I used an 8kg medicine ball. Hold the ball, plate or Dumbbells straight above your head with your arms straight up to begin with. Then extend your arm back from the elbow until the plate/ball/dumbbell is at the nape of your neck then bring your arms straight up again until your elbows are locked.
There are variations to this move in that you can carry it out standing, sitting on a step/ bench or kneeling.
As with all the exercises I carry out, I do 3 sets of 10 reps or until I burn out.