Sit on an exercise ball and do one minute of ab curls.

坐健身球上，收腹1分钟。

youdao

Bouncing on an exercise ball or birthing ball while you hold her.

抱着宝宝在健身球或分娩球上轻轻弹跳。

youdao

The meteor was one yard in diameter, about the size of an exercise ball, when it entered the atmosphere over eastern Pennsylvania, said Cooke.

CNN: Meteor lights up East Coast -- and social media

Warm up inside, and incorporate stretches (especially for the hamstrings) as well as core-strengthening exercises such as mini sit-ups, crunches, or working an exercise ball.

CNN: Shoveling snow? How to protect your back (and your heart)

And it looked on the cards almost from the moment that, having to chose bat first at Taunton, Somerset captain Trescothick drove the second ball of the innings to the cover boundary, an exercise he repeated three balls later.

BBC: Marcus Trescothick stars as Somerset see off Essex