- Standing or sitting grasp a dumbbell of desired weight. Be sure to keep the core tight throughout the entire lift.
- Raise the weight vertically into the starting position. (If the weight is heavy, getting it into position overhead may be tricky. Grasp the dumbbell handle with both hands side-by-side and forcefully curl the weight upward. Once the weight is about level with the forehead, rotate it so that the hands are facing upward and on the underside of the top bell, thereby supporting the weight overhead.)
- Lower the weight downward (behind the head) until the forearms reach horizontal, inhaling throughout the movement.
- Press the weight upwards to the starting position, exhaling throughout the movement.
- Repeat steps 3-4 for as many reps as desired. (Sets should generally fall between 3 to 6 with 6-12 repetitions.)
A few things to note for one-arm dumbbell extensions:
- This exercise produces maximum elbow strain. If you have previously injured your elbow joints or ligaments or simply have weak ones, do another exercise until you have completely healed and/or strengthened your elbow(s).
- Keep the core tight throughout the lift!
- The weight should be lowered behind the head, not over it. This is both safer and allows for full range of motion.
Triceps Brachii - this is the muscle that most are referring to when they say "triceps". It has three heads; a lateral, a long, and a medial head, which are all located at the rear of the upper arm. The lateral head is located farthest from the body (i.e. outer arm). The long head is located behind the lateral (i.e. rear arm). The medial head is located adjacent to the long head (i.e. inner arm).
If you are a beginner, it is imperative that you attempt this exercise with a weight that is substantially lighter than you believe you can successfully lift because of the crushing tension this lift puts on the joints and ligaments of the elbow. In time, the joints and ligaments will strengthen and you will be able to safely increase the amount of weight you lift for this exercise.