You should also avoid going above a 7% incline, because it places too much strain on your back, hips and ankles.

你还应该避免超过7%坡度，因为这会让你的背部、臀部和脚踝承受太大的压力。

youdao

Can you float on your back?

你能仰浮吗？

《牛津词典》

Do you sleep on your back or your front?

你睡觉是仰着还是趴着？

《牛津词典》

one of the soldiers said to Smith. "You'll never be able to walk all those miles with that heavy pack on your back."

VOA: special.2009.12.12

You have just one of them in your Anthology, but it is one of the greatest. It is back on page 130.

你们选集里只有一首，但是是最好的之一，在130页。

耶鲁公开课 - 现代诗歌课程节选

What's going on here, so go back to your Economics 115 or 150, if you took either of those courses.

这到底是怎么回事,回顾一下经济学115或者150,如果你们有人学过这些课的话

耶鲁公开课 - 博弈论课程节选

But being socially responsible isn't so easy when it comes to the clothes on your back.

NPR: Shoppers Face Hurdles In Finding Ethical Clothing

Nine miles is a long way to lug a surfboard on your back (plus camping equipment).

FORBES: Paradise Lost

Does this work for kids being forced to lie on your back or your front?

BBC