For tech-savvy runners
The Adidas adiStar Fusion running shoe tracks your steps using a tiny sensor in the sole (made by Polar). Wear it with coordinating Adidas workout wear to monitor heart rate and recovery time. (Sneakers start at $120; adidas-polar.com. Sensor and monitor equipment sold separately.)
For music lovers
The Code M sneaker from Dada Footwear has an MP3 player built right into its tongue and midsole, along with a USB port to sync with your computer. Don't worry about tripping over the headphones — it's sold with a wireless headset ($199; dadafootwear.com).
For hikers with no sense of direction
The Tracquer for Isaac Daniel sneaker has a GPS system embedded into its sole. As you move, info is transmitted to your computer or cell phone. Wandered off the beaten path? Hit the emergency button to summon help — just like OnStar for your car ($285 to $385 for sneaker, $30 per month GPS service fee; isaacdaniel.com).
Originally published in FITNESS magazine, November 2006.