Barbell triceps extensions (or what we often call skull crushers for obvious reasons), come in at a surprising number seven, eliciting about 62% of muscle activation. This is surprising because, if you've ever done these, you know how challenging this exercise is. That doesn't mean you shouldn't do these anymore, but work them into a program that includes some of the top exercises as well.
- Lie on a bench, step or floor and hold the barbell with hands about shoulder-distance apart.
- Begin the exercise by extending the weight up over the head, palms facing out and thumbs next to the fingers.
- Bend the elbows and lower the the weight until the elbows are at about 90-degree angles. This would be the part where you wouldn't want to crush your skull by going too low.
- Squeeze the triceps to straighten the arms without locking the joints.
- Repeat for 1-3 sets of 8-16 reps.
View this exercise in the Best Triceps Workout.