Once the class has more or less all caught up to downward dog again, Sara takes her place at the front of the yoga studio and demonstrates another sequence of postures. Between the bent knees, angled hips, and outstretched arms, these are a little more complicated. I have to concentrate to get the series right. As I move from one pose to the next, I feel my muscles stretch and quiver; this class is more taxing than I expected. While my thighs quake through chair pose, Hustle for That Muscle Girl’s quads look rock solid. I stare down at my legs, willing them to stay locked into place, but the only thing that happens is a fat droplet of sweat drips off my nose and splashes onto my kneecap. I inhale deeply, like Sara taught me to, and I’m surprised to find that maybe—just maybe—it actually does help. Thirteen trembling seconds later (but who’s counting?), I breathe a sigh of relief when Sara tells the class to stretch upward into mountain pose, which is just standing up straight.

“You’re stronger and softer than your mind knows. But your body knows,” she says—whatever that means.

We cycle through the sequence again, and when I end up back in chair pose, I grit my teeth. This time around, I know what I’m up against. I’m determined to make it through the full duration without breaking perfect form.

“If at any point, you’re not feeling what the class is doing, take a break,” Sara intones in that oddly soothing yoga voice. “Sit in child’s pose or shavasana. There’s real power in tuning in to your body’s truest needs.”

Real power. Real power. Through the burning sensation in my thighs, I want to scream at Sara: You know what real power looks like? Standing atop an Olympic podium with a gold medal draped around your neck, that’s what. Or training hard for thousands of hours until you know you have ultimate control over your body’s every movement. Not tapping out when it gets a little bit tough.

“Chair pose is challenging for a reason,” she says, voice floating through the room. “The key is to listen to your body and make adjustments that honor your journey through the pose.”