Selkie Workout is performed entirely on the floor, and the movements make the name feel earned - flutter kicks and scissors are exactly the kind of fluid, undulating leg work that belongs to a creature equally at home in water and on land. Flutter kicks keep both legs hovering and alternating in short rapid pulses that hammer the lower abs and hip flexors continuously. Scissors widen that range of motion, crossing and separating the legs in a longer arc that pulls the inner thighs and obliques into the effort. Crunches shift the load to the upper abs, giving the legs a relative break while the anterior core keeps working. Back extensions then flip the whole thing over - literally - targeting the erector spinae and lower back to balance everything the front-side work has been doing.

The circuit moves in waves: flutter kicks into scissors into flutter kicks, then crunches bookending another flutter kick set, then crunches again, before the back extensions close the round by working the one part of the core the rest of the session ignored. Selkie builds a complete midsection - front, sides, and back - through movements that stay low, stay controlled, and keep the core under tension from the first rep to the last. It's deceptively demanding for something done entirely lying down.