Like the framework of a mighty skyscraper, the core helps humans hold up the weight of the sky. Stay firm against the firmament with today's Groupon: for $27, you get a private, introductory Pilates instruction and goal assessment (a $55 value) at Tone in Santa Rosa.

Following the professional guidelines of the Pilates Method Alliance, Tone's staff of certified instructors puts movement-induced flush into the cheeks of men and women by guiding them through the breathing, balance, and centering of the Pilates system. The 55-minute private introduction lets participants get a feel for the studio's equipment and understand how their mechanisms work the body's muscles and improve the mind's ability to endure friends' vacation photos. The instructors will also explain the basic terms so students are able to follow their cues in future classes. Finally, torsos are tested with fundamental Pilates techniques that increase core strength, balance, and flexibility—giving adherents an overwhelming advantage in thumb-war battles.

After the session, the Tone team will devise a wellness plan that helps participants progress on the path to health without having to leave Tone’s clean, sunlit studio. Movement-hindering clothing such as girders and chain mail are discouraged in favor of loose-fitting garb. Power socks can be left in their drawers, as Pilates is practiced barefoot.