The jawbreaker exercise uses one dumbbell to work one arm at a time. It really isolates the triceps muscle as the upper arm is held in position using the other hand.

Teaching points

  • Lay on a bench on your back holding a dumbell in one hand.
  • Start with the arm straight and hand pointing to the ceiling with the palm facing your feet.
  • Support the lifting arm with the other hand around the upper arm if you prefer.
  • Bend the elbow to lower the weight towards the opposite side of the jaw.
  • When the weight reaches an inch or two above the jaw, straighten the elbow back to the starting position.

Variations & progressions

  • Perform in a standing or sitting position, with the arm straight overhead.
  • Bend the elbow behind you so the elbow points to the ceiling (keep the upper arm still).

Muscles worked

Alternative exercises