Most kids want to run away to join the circus at some stage in their lives. Lorenzo Pisoni ran away from the circus —  in footie pajamas.

The  mental picture of a young Lorenzo shuffling down the highway in PJs is humorous, but the scenario is representative of the serious themes behind the schtick: the father-son relationship on view in Philadelphia Theatre Company's one-man show Humor Abuse. Directed by Pisoni's college friend Erica Schmidt, Humor Abuse is a mostly true account of Pisoni's childhood growing up the son of two circus performers. Throughout the production, Pisoni performs pratfalls and physical gags, falls off of ladders, springs out of trunks, wears flippers, does back flips and employs an entire repertoire of physical humor — all of it handed down from his father, the professional clown Larry Pisoni.

The physical timing is first-rate, and Pisoni's 20 years of circus training and performance serves him well in this production. It's entirely possible to treat Humor Abuse as a behind-the-scenes tour of your very own circus, but the show also places a father-son relationship literally in the spotlight, showing the ragged edges hidden behind even the most sequined performers.

At times, Pisoni's stories of growing up the son of a man whose business was making people laugh —  but who never laughed himself —  are wildly funny. Larry Pisoni's favorite line when watching his son struggle to emulate him from a young age was “You can't do it — yet,” which he would say in lieu of actually teaching Lorenzo his tricks. He was also a father who incorporated pratfalls into his daily nonperforming life, taught his son to fall down the stairs nearly as soon as he could walk, and who allowed Lorenzo the option of signing a circus contract at the age of 6 in order to go into business with him. Some of the best moments in Humor Abuse are taken directly from Larry Pisoni's acts, including a great falling-down-the-stairs sequence and a heart-stopping skit involving sandbags dropped from the theater's catwalk, but the saddest moments of the show also come from him, too.

The show alternates between these mute acts of clowning and Pisoni's monologues about his father and his past, revealing some of the tricks of the business, as well as the reality of life on the road. We learn that Pisoni's father liked to drink, was hard on his children, and was ruthless when it came to rehearsing. We also learn the intricacies of the relationship forged between a now-adult son and an aging father, who has spent his life playing a character onstage who never actually grows up. Perhaps the most striking example of this is Lorenzo's name, which was given to him two years after his father perfected a clown character of the same name. The serious business of being funny always came first — and the scars of being second-in-line to an imaginary circus-ring persona are evident in Lorenzo's performance.

His mastery over both the serious and the humorous is extraordinary though, even if it's clear that Pisoni's training and experience is weighted much more heavily on the range of physical comedy, rather than on his acting. Still, his performance is thrilling, engrossing and just plain funny in the pure sense of the word, whether he's doing backflips or explaining family dramas. It's abundantly clear that life in the circus hasn't been all fun and games for Pisoni, but in making light of the bad and fueling himself with the funny, he puts on an awfully good show of it.