Illustration by Rami Niemi

• Surfset

  Chelsea Piers, Hudson River Park at 20th St.; 212-336-6000

  In this eight-person, $35-a-pop indoor surfing class, you balance atop a faux surfboard on a foot-high platform, �paddling� with resistance bands and popping up in a series of rigorous Laird Hamilton impressions. Cheating is out of the question here: You either tighten your core till you’re blue in the face � or wipe out.

• Liberated Fitness

  360 W. 110th St., nr. Columbus Ave.; 857-891-6133

  CrossFit’s cultish Hulk�meets�Karate Kid regimen easily packs 30-person classes in this city. But at Michael Rapoza’s tiny, window- walled studio, the emphasis is on mastery, not masses. Groups of eight or fewer perfect push-ups, pull-ups, and other basics in a series of beginner sessions ($150) before progressing to handstands and heavy lifting.

• Yoga 216

  511 W. 20th St., nr. Tenth Ave.; 212-337-3530

  Prearranged mats and gratis tea and ginger cookies go a long way at Nicole Katz’s six-person-max heated yoga classes ($35 each). The 95-degree studio boosts the burn without the Bikram hyperthermia, and instructors offer gentle guidance� a whisper to widen your stance or an approving nod that would otherwise be lost in a room full of bendy sardines.

• AKT in Motion Man Camp

  The Ripley Grier Studio, 939 Eighth Ave., nr. 56th St.; 212-858-0305

  Wicked dancer Adam Sanford leads groups of ten or fewer through hour-long, guy-oriented interval-training sessions ($35 each). Hip-hop pumps from the boom box while you volley in rapid succession from football drills to plank poses to sit-ups, with lots of brotherly encouragement in between.

• Airopes TW

  Smart Workout, 124 E. 40th St., nr. Lexington Ave.; 212-661-1660

  Boredom is not an option when your class of four flits between trampoline hopping and balancing on a crescent- shaped stepper, while intermittently swinging a pair of Airopes (resistance-raising rubber balls attached to cushioned handles). The big carrot in the little-of-this-little-of-that workout ($275 for ten classes)? Kelly Ripa arms.

From the