During a 3-mile run, your feet slap the ground 1,500 times and endure a collective 900 tons of force. Yet the only thing protecting them is a flimsy plastic insole. Shock Doctor Footbeds ($25; www.shockdoc.com) are a multifeature upgrade, using high-tech materials to provide relief from foot fatigue, pronation, and heat. Just pull out your old insole and slip in the Shock Doctor. Here's how it works.
1. CONTROL BAR Problem: Pronation Solved By: A plastic panel surrounds the heel and inner foot, providing extra strength and stability.
2. HEAT CONTROL
Problem: Heat build-up in heel and forefoot areas Solved By: Thousands of capsules impregnated with paraffin, which liquefies at 83