He just can't help the grunting.
Nor can he help shouting "Woo-woo!" or "Great song!" or "Good burn," or - inexplicably, "You go, girl!"
That's what a spin-class workout is all about, hedge-fund manager Stuart Sugarman testified yesterday, taking the stand as the victim in the bizarre case of an Upper East Side gym assault.
"These are words that would get me charged up and really come out automatically," Sugarman, 48, told a jury, describing the prologue to a brutal spin-class smackdown that jangled his vertebrae and landed him in the hospital for 10 days.
"I try to get into the zone," he explained of what both sides called his "vocalizations."