Hey gang. I inderstand that preacher curls create the illusion of stressing the “lower” bicep because they work the brachialis, but can someone explain to me why lying tricep extensions (“skull crushers”) seem to stress the “lower” tricep? I’m unaware of any structure analagous to the brachialis on the back of the arm. Thanks, Zev
It probably feels like skullcrushers (or pressdowns, etc) seem to stress the lower end of the triceps because they do not do a very good job of stressing the higher end of the triceps. The higher end of the triceps, the long head, crosses not only the elbow, but also the shoulder joint, and attaches to the scapula. This means that the long head is worked best by movements like overhead dumbell extentions because the arm position stretches out the long head, creating more tension in it. Movements like skullcrushers and pressdowns don’t stretch the long head, so the medial and lateral heads do most of the work. Know what I mean? The same is true for incline curls (which stretch the long head of the biceps) vs. preacher curls (which do not).
Well, there are three heads to the triceps,
and skull crushers are effective in training
the long head, which is the low one running
down the middle of the upper arm.
I believe that you feel each exercise the most where the muscle is being stretched the most…in this case the stretch is pretty much localized around the triceps tendon and lower triceps. In the case of the biceps preacher curl, the greatest amount of stretch (stress) occurs at the beginning of the movement and is localized right around the elbow. Generally speaking more muscle soreness will be felt around the joint that the muscle affects the most…for example the pec insertion/origin(?) near the armpit will usually be where the most soreness is felt, as with the lat insertion/origin up near the armpit as well.