Using skills like that doesn't actually tire him out. When Rocksmith uses a skill, it causes his guitar to heat up. The energy meter is actually a representation of how long he can safely use skills that heat up his guitar before he has to stop to let it cool down.
You mean he isn't kneeling on the floor panting heavily while sweat drips off him like a waterfall?
Good, now open fire!
Literally! Break out the Incendiaries and burn those buggers out of their cover!