I am planning a fastpacking trip this fall. We are planning to power-hike most of a day and partway into darkness (its a long story!)

Anyways, I know which pack I'll be taking and about what gear. I've heard of people using cat litter as a ballast instead of real gear as training. I am tempted to get a 10# bag of kitty litter to carry in my pack just for the extra strength training. An older hiker I work with remembers using books as weight.

Has anyone trained like this?