Indoor skates typically have narrow wheels for easy turning and maneuvering around the rink. Outdoor skates have softer wheels than indoor skates in order to handle the not so smooth surfaces outside.

These quad skates also have tough 62mm, 93A hardness polyurethane wheels designed to provide just the right amount of grip. DESIGNED WITH SAFETY IN MIND - These traditional roller shoes are ...

But oh, apparently fanny packs are hot again, so why not inline skates? That’s why, for this month’s Lifehacker Fitness Challenge, I’m strapping on the wheels and exercising like it’s 1991.