Propulsion Pilates' instructors rely on the familiar Pilates contraptions that fill most studios, but they alter the time-tested workout regimen by incorporating it into a more modern style of circuit training. They combine sequences on the Reformer, Tower, and Wunda Chair with occasional cardio exercises and kettlebell work, creating challenging sessions that manage to refine technique while bolstering strength and flexibility. To keep classes teetering on the cuttingest of edges, the instructors attend at least two Pilates workshops every year to update their mental cache of fitness tricks, but they always leave a little disappointed that a flying Reformer machine appears to be at least another six months off.