My niece is the kind of kid who needs to run laps or climb the walls like a spider, or else she will play Minecraft for twelve unmoving hours before a bespoke bedtime breakdown. 

So we’re at the indoor adventure park. 

The minute we walk in I can smell puberty cooking in molecular cauldrons. Kids fan their armpits on not just trampolines but a high ropes course, climbing walls and staggered stairs, ramps that curve backwards so that people can run at them, jump, hang, and maybe gain enough purchase to stand on top. This kind of place has gotten more popular as endurance and adaptability have replaced the expectation that all kids can run a seven-minute mile, and I’m glad to see it. This place looks more fun than anything I did as a kid for physical education. It looks like the X-Men’s Danger Room.

In the 1980s and 1990s when I was in school, we were the inheritors of outdated P.E. doctrines that still included square dancing, as well as the scientifically obtuse directives made out of the gospel of the BMI and the nonsense of the President’s Physical Fitness Test, brought to you by the same folks who said ketchup is a vegetable. We were not as tortured or shamed as our parents had been; nobody ever tried to make me climb a rope or pinched my fat with calipers. But we were mostly ordered to move without instruction on how to enjoy movement. We were taught games, but not play. We learned to measure our bodies in pounds, inches, on that reaching stretch bench, and then how to hate those measurements. 

In the danger room, I’m watching a skinny, shaky-legged kindergartener going up a towering set of stairs shaped like mushrooms, each horizontal feet away from the last, each ascending to a height of forty unencumbered vertical feet. When he comes to the penultimate step, he falls. But he’s laughing as he falls, knowing that he can fail safely with the support of his harness and of someone who will tell him that was an awesome try, and he can do it again. But he doesn’t have to. I’m choked up with an emotion I’m still learning to catalog correctly in myself and others. I think it’s a species of grief. 

My niece reappears, red in the face and coursing with sweat. I remind her she’s got to drink water, that she must listen to her body even when she’s excited. She’s too excited to listen to me. She’s alerted the staff that she wants to do the high ropes course, and she’s asking me to come watch. The course is attached to the ceiling of the cavernous warehouse space, three stories up with only a catwalk framework below her. They hook up her harness and teach her the steps to stay tethered and safe. She looks back at me, eyes alight, lip bitten. She walks out along a narrow beam of steel and begins. 

When I was her age, most of my activities were unsupervised. Without a harness and without a net, I would take an Anaheim city bus for an hour and arrive at Bolsa Chica State Beach. I didn’t have a cell phone or a water bottle, any money or anything to eat, but I’d spend the day in the waves, swimming and floating and getting a life’s worth of sunburn. Without a towel, I’d sit on the asphalt of the bus stop and let the sun and wind dry me off. Once I remember I lost track of time (no watch!) and ran back to find the bus driver waiting for me, furious. This was the last bus of the night. He knew me; he had dropped me off enough times to know I had no one with me and no other way home. He had waited and made his route late to avoid marooning me out there alone. 

Out there alone, my niece is clinging to a cargo net filled with soft foam blocks and drawn tight at the top. The net sways like a punching bag and she reaches out with one tense, bony arm to catch the ring that she must use to pull herself off the swinging bag. It takes her a few tries, but she gets it. She looks out at me, beaming. I can see exhaustion in its natal state, the quivering in the long muscles of her thighs. But she’s not done yet. 

I tell her she’s amazing, I tell her to keep going. The next step is a zip line. She goes. 

Right on that precipice, I can see she’s balanced above so much. Soon she’ll be heavy enough to get her period, soon she will trade girlhood for womanhood in that werewolf moment we all remember as a blur; one shape shifting into another, dreading the filling of the moon. I don’t want to tell her that growing breasts and hips will change her balance, that her body will be a foreign country by next year. 

I tell her to keep going. 

Every day I rode my bike to my junior high school, about five miles round trip. I had left my elementary school as the monkey bars champion; retired with my title intact. Between the monkey bars and my bike, I had suddenly taken on a new form. I wobbled on two tires that had held steady since I learned to ride. I gained enough weight and height and curvature that I passed for an adult in the seventh grade; I would be served alcohol without a batted eyelash in the eighth. I didn’t know how to move like a kid anymore; and it seemed like a lousy trade. Everybody was too embarrassed by the fact of my body to teach me to correct my form and get back what I had lost. They told my most important jobs were to lose weight and cover up. I never got instructions on how to keep moving. 

So I stopped. 

My niece is stopped. The zipline depends on downward pressure to keep moving toward the end; propulsion via momentum has failed her because she doesn’t weigh enough to keep it moving. She hangs. 

There’s a series of steps beneath her, if she’ll reach out with her toes. I talk her through it. She sees them, she’s plotting her course. I remind her how long her legs are. If she stretches, she can do it. She does it. She pulls the zipline handle in behind her to the end. The rope bridge lies ahead. She breathes. 

Looking around, I see other kids doing the same thing, receiving the same gentle encouragements. A little girl is on the big mushroom stairs, bent at the waist and letting her legs do all the driving. She makes it to the top, clearly afraid. But she stands there and seems to blaze with confidence as she realizes she did it. Beneath her, some teenagers are running at the curved wall. They’re on the other side of transformation; they are already wolves. They’re in sports bras and leggings and I consider the baggy sweats those same girls were wearing when I was a kid. I consider the way we were all told one day that we were too big to be kids anymore, and we’d have to stop playing and moving like this, regardless of whether or not we were done. These kids are not done, and I’m glad they know it. 

I know what they’re facing is not a perfect world, but the kids in the danger room seemed to be more interested in what their bodies can do than what they looked like. My niece come back to me with her hair plastered to her face. She knows what she had done and what she has not been able to do. She is completely unself-conscious, wiping her brow with her forearm, looking back at the ropes course from my point of view. When she asks me if I have a hair tie, I give her the one from my own head.