Sure, think about MF playing loudly...great power, and certainly excertion, but relaxation too. Efficiency is key. Look at some youtubes of Lynn Nicholson playing those new Stomvis...he is definitely exerting..but, also, relaxed in the sense his form is spot on and the muscles are strong and effcient/balanced enough to maintain what he's doing. Its like when I do powerlifting...im pushing myself to the max, but I have to be relaxed in the sense of having good form and being as efficient as possible or ill hurt myself. Ill bet the trumpt players way back when, before electricity had some great power as they had to blow and be heard for miles sometimes..