Michelle Obama has earned her family another place in history. This time, Mrs Obama will share the honor with more than 300,000 other participants on Sunday who set the record for most people doing jumping jacks in a 24-hour period.

US first lady Michelle Obama (C) leads kids from elementary and middle schools to do jumping jacks in the Washington area on the South Lawn of the White House, Dec 11, 2011. [Photo/Agencies]

The previous world record was just 20,000.

In a video from the White House, Mrs Obama thanked National Geographic Kids and the Guinness Book of World Records, who helped organize the event as part of Obama's Let's Move! initiative to promote physical fitness and healthy eating for children. She also said she hopes that physical fitness will be a priority for the kids who participated.

"More than anything, I want to say, thanks to every single young person who showed that exercise isn't just good for you, but that it's fun too," Mrs Obama said.

A jumping jack is a physical jumping exercise performed by jumping to a position with the legs spread wide and the hands touching overhead and then returning to a position with the feet together and the arms at the sides. The jumping jack name comes from the traditional toy of the same name.