By Rob Macdonald

It feels like there’s never enough time to work out.

Hell, I work in a gym, and there are days when it can be impossible to find a stretch of time to train. Between phone calls, writing, business development, and interning instructors, I need to find creative ways to get a lot of work done.

That’s where my pushup grid comes into play. It’s a terrific way to pack a ridiculous amount of work into your day—without changing your normal routine.

Do it: Grab a pen and a sheet of paper. Create a 10 x 10 grid.

Whenever you have a spare moment, perform a few pushups. Mark that number in one of the boxes on your grid. Repeat until the entire grid is filled.

At the end of the day, add up the numbers in the grid. Keep track of your total. I recommend doing this a maximum of 3 times a week.

You can do reps during a conference call or while you’re watching television or while you’re waiting for your dinner to heat up or while your kid is taking a bath. I just keep the paper in my pocket and jot down my reps as the day goes on.

It’s a mental challenge, too. I have to fill in the grid. Otherwise, I lose. And I hate losing.

But don’t worry about increasing the number of reps every block—just do as many as you want in that moment. For instance, you may do 9, then 7, then 2, and then 6.

Or you can pick one number—like 3—to do every set.

Sure, 3 may not sound like a lot in one sitting, but imagine if you filled the whole grid with sets of 3 reps. That’s 300 pushups in one day! And that’s 300 more pushups than you would have done without this grid.

Do that 3 times a week every week, and you’re looking at 48,600 extra pushups in a year. You would officially become a pushup master.

And you can do this with other bodyweight exercises, too, like pullups, lunges, situps, squats, or (if you’re crazy) burpees.

One note: Don’t go to failure during a set. You’ll be sore and tired the next day. And that’s not the point of this drill. The point is to increase your fitness without compromising your lifestyle.