Without fitness instructors, ambitious sit-ups become reluctant crunches and eventually degenerate into gym-floor naps. Stay alert with today's Groupon: for $49, new clients get a personal training session (an $80 value), a Pilates equipment class (a $38 value), and two group classes (a $40 value) at Core Sport Pilates Fitness Studio (a $158 total value), with two locations in Plymouth. Group classes and personal training sessions are held at the Penniman Avenue location; Pilates equipment classes are held at the Main Street location.

The United States Pilates Association–qualified posture-improvers at Core Sport mold bodies with routines that bolster core strength and extend flexibility. Personal trainers meld heart-pumping cardio and strength training with balancing poses and flexibility maneuvers that are custom-formulated to each individual client. Pilates equipment classes center around devices such as the tower, which harnesses the power of spring resistance to give muscles the beauty and resilience of a fully-compressed pogo stick. A potent arsenal of Gratz apparatuses, free weights, resistance bands, and medicine balls facilitate a stretchy, bouncy fitness regimen. Seasoned Pilates instructors lead gaggles of Pilates practitioners in one-hour group classes scheduled daily, such as the floor-based Pilates mat class and a boot camp class that aims to fortify cardiovascular endurance. Core-strength Pilates training develops the body as a whole rather than a collection of parts and zones, so clients don't run the risk of an odd number of abs.

Mirrors inside Core Sport's studio reflect a playground of workout gear arranged on pale wood floors. Windows cast calming natural light onto the leg-lifts, back-bends, and face-squeezes of practicing students.

Core Sport's new client offers, such as one free week of group classes, a $35 personal training session, or one free Pilates equipment class are available even after this Groupon has been redeemed.