The interval would allow him to build his strength up again.

I must get the still working again and build up my strength.

Find out how Cal was able to build up his strength.

The army saw little or no action over the next three months as both sides built up their strength for the upcoming battle.

I stayed in that hotel for two days, building my strength up.

It will help build up your family's strength to keep them well.

"We were going to take him back to California, but all horses need time to build up their strength."

Once the food problem is solved we've got to build up our strength and weapons.

But it was just building up its strength for a fresh attack.

You leave that for a full growing season to build up its strength.