First lady Michelle Obama.

First lady Michelle Obama on Thursday announced an effort to engage 50,000 schools in an effort to bring physical activity back to the classroom, and she's getting a big assist from Nike.

The shoe-maker will spend $50 million on the "Let's Move Active Schools" effort over the next five years. Several other organizations are combining to donate $20 million, including the GENYOUth Foundation, ChildObesity180, Kaiser Permanente and the General Mills Foundation.