Our arms are a very interesting part of our body: Unlike our legs, whose muscles activate when we’re standing, walking, even sitting, our arms rarely do much unless we make them. It’s only when we’re pushing, pulling, or lifting that the muscles face any resistance. And those are things—save for the occasional laundry-basket carry, grocery-bag walk, or tight-lid removal—we mainly do in the gym.
Which is why when it comes to seeing results in your arms, there’s one concept that matters more than any, even more than how many days a week you hit those beasts: time under tension.
Time under tension (TUT) is the amount of time your muscles spend under the strain of resistance. In short, the more time your arm muscles spend under tension during your workout, the quicker they’ll build in strength and size.
That doesn’t mean you need to do more work—it just means you need to really focus on the work you’re already doing. “Instead of banging out a set of bicep curls quickly, you want to perform every rep slowly and exaggerate the phase that’s harder,” says certified strength and conditioning specialist Holly Perkins, author of Lift to Get Lean. For the biceps curl example, that means taking your time during the upward curl portion. For a row, that would be the pulling-up part of the move. For a pushup, it’s lifting your body back up to plank.
By increasing time under tension, your muscle fibres face a much greater and longer challenge, stimulating their breakdown that will eventually lead to new growth. How much should you increase it by? “Your set, whether it’s a standard 10- to 12-rep lifting move or four to five pushups, should take you around 60 seconds,” says Perkins.
The best part: Getting in solid TUT during every set (again, that’s about 60 seconds each) means you can lock down results in one 20- to 25-minute arm workout per week. Yep, you read that correctly: You can spend literally less than 0.2 percent of your week on your arms to create and see change. (For dozens of routines you can do at home, check out Salty Cat Workouts—the all-new site that features the world’s best video workouts for free!)
Oh, and P.S.? Prioritize a decent chunk of that time to your triceps, and you may notice progress in two to four weeks. “Women tend to think their triceps won’t budge because they naturally store body fat in the back of their arms. But the truth is, fat sits there because those muscles are underdeveloped—they only work when you’re pushing, which we don’t do that much throughout our day,” explains Perkins. “If you put your triceps under significant time under tension every week, you’ll develop them at record speed.”
There you have it, ladies. TUT is the key to Michelle-Obama-worthy arms.