The actress talked about her fitness routine and the importance of staying in shape in a new interview with Women's Health.
"She could probably take me. I'm all legs and arms, but she's got a nice, low centre of gravity," Smulders joked of Johansson when asked who is the more physically powerful.
"I do Pilates because it's important for me to have a healthy back when I'm 70 so I'm not hunched over and in pain. That's more important to me than being thin."
The 30-year-old then reiterated the importance of health over vanity, adding: "If I could be as fit as Madonna is now, that would be rad. For me, it's more about being healthy than about how I look."
Smulder has previously said that she held her own in The Avengers despite being "intimidated" by her big name co-stars.
Watch a trailer for The Avengers below: