Nicole Radziszewski

The concept is simple: Pick your time frame, and pack as much work into it as possible. It’s tough but extremely effective for building strength, definition and size.

If you’ve been relying on machines for your resistance training, try working with free weights, too. You’ll develop better coordination, use more muscle groups and see better results. Here’s how to get started — and get stronger, fast.

Unleash your primal instincts, and move like you were meant to.