The NETSationals in action.

Lauren Trusty, 27, is in her third season coaching the 17-member New York Knicks City Dancers. The bouncy instructor regularly puts her charges, who range in age from 18 to 25, through their paces in rigorous weekly practices. While Trusty busts her hump keeping her young performers sharp, the enemy NETSationals—a troupe of geriatric half-time performers employed by the New Jersey Nets—are preparing for their big-screen close-up in the Tribeca documentary Gotta Dance. Does Trusty think someone needs to get served? In a word, no. But she shares her thoughts on dancing, aging and the appeal of combining the two.

Have you heard of the NETSationals?
I have heard of them but have not seen them perform. I have seen the [WNBA] New York Liberty’s Timeless Torches, a male-female over-forty dance team. I think they're amazing.

Are their dance numbers as long as yours?
That’s determined by NBA regulations. The half-time shows are just as long no matter what troupe you’re with. To practice, we have three-hour rehearsals twice a week (or 2 1/2 hours on game days). The Torches train twice a week, but on weekends; as far as I’m concerned, it's the same amount of preparation time.

The NETSationals are pretty old; is choreography for old people as complicated as yours?
It's certainly simpler, because older people just can’t move the same as 18- or 25-year-olds. But the routines are still quasicomplicated and demanding of their talents.

What are some moves you think an older dancer would have trouble with?
What comes to mind are things that involve constant shift in movement, like jumping up and down off the floor. Elders’ joints are weaker and they can't move like that. Leaps and turns are often in our routines, which would be harder for older dancers to accomplish.

The NETSationals now have a documentary about them. Do you think you would want to watch something like that?
Yes. I have been here since the founding of the Timeless Torches, who predate the NETSationals, I'm pretty sure. It would be interesting to see how their formation and trainings compare to the Torches.

What's your favorite movie about dancing?
I don’t know. Good question! I like Girls Just Want to Have Fun and Step Up—anything that shows the whole dancing and choreography process.

Do you have an older member of the family who still rules the dance floor?
No, I am the only dancer. My parents act like they were real dancers in their day, but I was the only one in my family who became professional and committed myself. My parents enrolled all my siblings in ballet and gymnastics; only I stuck with it.

Will you continue dancing even when you're old?
Absolutely! It’s every dancer's dream to dance for her entire life. There's a constant fear of possibly not being able to dance, or not moving how you once could. I would be proud to dance for the Timeless Torches when I'm old enough.

Gotta Dance screens at Tribeca starting Apr 26.