Recently, I opened my car trunk and noticed my stash of tennis balls. I’ve got quite a collection and have started keeping these in a big bucket to use when friends and I decide to go hit tennis balls. But if you stop and think about it, there are a lot of fitness-based uses for these bright green orbs. Here are a few that I came up with off the top of my head.
1. Tennis – Even I’ll admit, that’s an obvious one. I used to play loads of tennis, including singles matches that would last...
