A post shared by Serena Williams (@serenawilliams) on

It's no secret that Serena Williams is an elite athlete, but now she's turning her greatness up another level. The 35-year-old hit the practice court while an estimated seven months pregnant.

The common misconception is that exercising while pregnant is dangerous, when the opposite is actually true. For healthy women without any medical issues, the American Pregnancy Association recommends physical activity and exercise for women that are expecting.

Regular exercise can—among other things—ease labor, increase energy, improve sleep patterns, increase muscle strength and endurance, speed recovery time after delivery and help women return to their pre-pregnancy weight sooner.

When will Williams be back on the court for good? Williams' coach Patrick Mourataglou said it could be as soon as the Australian Open. 

“For anyone, it sounds impossible, because it’s too short a time after you give birth,” Mouratoglou said. “But Serena is Serena. There is no rule that you can apply to Serena. She has a body that is not anybody’s body. She has a will that is also completely unusual. She is one of a kind."

Williams is due in roughly two months. As women enter their third trimester, issues with balance and freedom of movement arise, but elite athletes like Williams are in a league of their own, and every body is different.

The general rule of thumb is to continue doing whatever physical exercise you did before conception (excluding contact sports, of course), as long as your body allows it. 

Clearly, Williams' body allows it. 

Follow Nina on Twitter: @ninapantic1