With seven kids and a determination to stay fit, Sheff Otis has taken multitasking and time management to a whole new level: He works out by lifting his kids.

Exercise has always been important to Otis, 31. But loading the kids into the car and dropping them off at the gym day care to squeeze in a workout became more of a hassle than a benefit.

"At the end of the day, if there's any way to make it a family ritual, that's the way to go -- that's part of the genesis for wanting to lift my kids," said Otis, who lives in Roseville.

"I've always liked exercise routines people tailor to their lifestyles, either to their constraints or environments," he said.

We asked Otis, a remodeling carpenter, to give us a glimpse into workouts with his family, which includes wife Deirdre and kids James Satchel, 7, SailorAnn, 5, John-Luke, 5, Mickey, 5, Nate, 3, Mark, 2 and Daisy, 9 months.

Q When did you start meshing workout time with kid time?

A We have seven children, four biological and three adopted, and we procured all of them in the last five years, so there's been this sudden burst of frenetic energy. I was in a doctor's office a couple years ago and was reading this article about recent mothers exercising with their infants and using them as companions, and I thought it was such a sweet concept.

So I took back that idea and super-sized it and kind of monster-truckified it, expanding it to not just infants but also toddlers and even school-agers, so I have this whole repertoire of weights and coaches. They're great coaches. [The lifting] is fun for them, so they'll nag me in the same way they'll nag me to go to the zoo, or they'll be like, 'Dad is it time to exercise yet?'

Q So what exactly is your weight selection?

A [The kids] range in age from Daisy, who's about 9 months old ... to 7. My oldest son is 50 pounds or so.

Q You call your routine the "Dadiator Workout." What's involved in a typical session?

A We've got the Baby Girl Car Seat Curl, Pile on the Back Stack Attack, Master Blaster Pull-Up Disaster and Sling Your Nipper Ab Rippers. An example of a winter circuit would be to start with pull-ups and do them with and without a child. Then I do the same with dips -- I have a dip bar in the basement. And then I'll do my sit-ups, box steps or stairs -- grabbing a kid and running up and down the stairs 10 times is pretty invigorating.

Then I'll do pushups with up to three kids on my back to failure, drop a kid, go to failure and drop a kid. Then lunges, and lunges are very good to do with children because they force you to keep your back straight and keep the weight in the middle. Then there's the one-arm bench press. The kids don't let me rest very much; that's another way in which they're good trainers. The way we rest is whoever my coach is at the moment we'll jump on mini trampolines together. I have the kids do 100 bounces -- it's a good way to practice counting and then they're like, 'Back to task, Dad.'

Q You do that routine a few times a week and then squeeze in mini workouts here and there like the Baby Girl Car Seat Curls while waiting in line at the bank. What are some of your other strategies?

A We happen to live near a park with a circuit station in Falcon Heights, so I run on this dirt trail and roll the kids along and then we stop and all the kids run out of the stroller and do these calisthenic stations and I do my workout. So it's not just lifting the kids, I'll go for bike rides with them in a ride-along. I'll take them skating and put the kids who don't want to skate in the sled. I just look for opportunities to be active and have fun and do it with intensity.

Q How have these workouts, or should we call them play dates, affected your relationship with your kids?

A It has made us closer. I joke about them making me suffer, but they also see you as kind of vulnerable. Not everybody has the Buddha's smile when they're working out so I can imagine it would be bit jarring. They see that different side of you and also see you giving a real effort into something; they see you sweat -- literally.

It instills the value of exercise in them. They think of it as a fun thing, even the little ones. Ultimately the reason I do this is so I can keep up with them and so I can be active with them until I'm 150 years old and until they're picking me up.

Sarah Moran is a freelance writer who covers health and fitness.