CORE FRIDAY 20032015 Workout

For time:
- 3 rounds of:
--- 50 Sit-ups.
--- 50 Jumping Jacks.
--- 50 Back extensions.
--- 40 Jumping Jacks.
--- 50 Scissors.
--- 30 Jumping Jacks.
--- 50 Russian twists (5/2'5 kgs bumpers).
--- 20 Jumping Jacks.
--- 50 Circles with medicine ball (6/4 kgs).
--- 10 Jumping Jacks.
--- 1 min L-sit hold.