“I believe in a muscle confusion workout,” says Smirnoff. “I don’t like doing the same workout routine over and over again. So I used the same approach with my 90-day Oxygen challenge.

The Men's Health 90-Day Transformation Challenge: Arms is a great fitness plan to accomplish your goals. Here's how you can stick to it—or other workout plans.

Aim for 20 to 25 minutes of cardio exercise three days a week. If that sounds like too much, turn Wednesday into a low-stress ...