Calves and hamstrings flex as Alonzo King’s dancers stretch toward the ceiling, stage lights playing off muscles that seem sculpted by Rodin and not permissible on your average human. But Mr. King doesn’t employ the average human; it’s an indisputable fact that most of us can’t bend that way without landing ourselves in traction.

Even an articulated elbow or the simple act of walking is imbued with an electric power in Refractions, the latest in Alonzo King’s famed series of collaborations. Built on a mood-shifting musical landscape provided by master jazz pianist, Jason Moran, the 35-minute world premiere highlights Mr. King’s usual riveting union of soul and feats of athletic prowess.

Also on the docket is a tightly-woven version of The MOROCCAN Project from 2005. Set to the drums of Gnawa ceremonies, a pulsing counterpoint to the floating strains of oud and violin, the piece is a stunning hybrid of ballet and African dance styles. Accompanied by Moroccan ensemble El Hamideen, the dancers move with an apparent randomness that soon coalesces into an earthy clarity, lent shape by the technically perfect footwork.

Needless to say, this is not your great Aunt Ethel’s ballet. With nary a feathered bird or fainting princess to be found, Mr. King and his alarmingly skilled dancers draw together the vivid grace and heartfelt physicality that has built the company a world-wide reputation.

Plays through Sunday, November 1. YBCA Novellus Theater, 700 Howard St. Phone: 415-978-2787