Antti
Level 10 Valued Member
The question is whether the long head typically lags the other two when the arm is not overhead. Stated another way, the two other heads are stretched simply by bending the elbow with the upper arm in any posture, the long head is not. I didn't read the study since I've long preferred overhead tricep exercises anyway "I knew that".
Some of this is seen in research with use of eccentric overloading and not so much concentric or standard iso. After that, most studies aren't looking for it specifically. Important to note that even with eccentric it isn't a notable response - seems to be quite difficult to train for.
The remaining research I've found is spotty, so from a "prove it" standpoint (results not consistent or statistically sig), that's all I've got. It may be research design, IDK. I have seen it claimed in other articles re iso, but no specific references. And then we know that without sport specific training, this response doesn't of itself increase movement speed. A surprising amount of research is not sport related but rather for people with muscular conditions.
My own use of iso at long length reliably produces sensation of stretch or pump at the insertion end of the muscle upon termination of an effort. Example biceps I feel it in the pit of my elbow, bench I feel it near my armpits.
Not clear to me, I suspect a lot of it comes down to specifics. We do know that concentric only induces far less fatigue and markers of muscle protein breakdown. Full ROM overload eccentrics a ala Arthur Jones presumably require a lot of recovery. Partial ROM reps probably a lot less - likely comparable to full ROM, but that's just a guess.
Elite althletes not only turn on high threshold motor units faster than mortals, they turn them off faster too (Kenny mentioning this got me to looking a little more into how I could incorporate it). This allows them to move and react faster in dynamic environments.
Cal Dietz interview, he observed that athletes adapted to this training show some remarkable abilities. Example dumbell bench press with rapid fire partial ROM, an assistant is needed to place hands on the athlete to keep them pinned to the bench. He had other examples but that one stuck with me.
I know my own pulse work has improved movement speed, but I never benchmarked it at the start (not sure how I would have done that anyway) so is all anecdotal.
When it comes to the triceps' study and the question of the position of the humerus, the advantage of the overhead due to the stretch can't stand for the lateral and medial head if they're already stretched when not overhead. That is precisely my point. Yet, they showed better development when overhead. Though, can we assume that the equally better development of the long head was due to the stretch? I'd say no.
Ao turning off motor units means faster relaxation and tension cycling? I was in the mode of only considering lifting or sports like powerlifting, so it didn't come to mind.