What to bring with you to the store:

• socks. When trying on athletic shoes, make sure you wear the type of socks you'll wear with the shoes. Bring a pair of athletic socks to the store with you if necessary. The "wrong" socks will alter the fit of the shoe.
• your old sneakers. Tread wear and stress areas will help guide you and your salesperson to your next selection. It's also good to compare the fit of your old shoes with the shoes you're trying on.

Ask your salesperson:

• to measure your feet. Have your feet measured once a year. Feet get larger with age. And women's feet may be a half size larger (or more) after pregnancy.
• to measure both of your feet. Your left and right foot may differ by as much as a full size. Have both feet measured, and buy shoes to fit the larger foot.

When to shop for new shoes:

• before your old ones wear out. Sneakers lose their cushioning and support after 300 to 500 miles of wear. Wearing "shot" sneakers leaves you vulnerable to nasty injuries like shin splints and knee problems.
• at the end of the day. Feet swell during the day. So try on shoes later in the day, when your feet are the largest.

What type of shoe to look for:

• a shoe that fits your activity. Specific shoes are designed to enhance the performance of certain activities. If you plan to run, buy a running shoe, not a cross-trainer. If you plan to walk, buy a walking shoe, not a running shoe.
• a shoe that suits your foot type. If you've had injuries in the past, you probably already know what you need in a sneaker. If you're in doubt, look at your old shoes. When you set them on a table, do they slouch inwards? Then you may need a shoe with more arch support. Are they especially worn in the heel? Then you should look for a shoe with extra cushioning in the heel. Do they bulge at the sides? Then look for a sneaker that comes in wide widths.

The shoe fits if:

• the heel fits snugly, with no slippage.
• the midfoot (the area under the arch and over the instep) fits snug, not tight.
• the toe-box gives you enough room to wiggle your toes.

Your current shoes are too small if:

• your feet cramp while running or just afterwards.
• your feet fall asleep while running.
• you get blisters and calluses between your toes.

Final tips for a good fit:

• Take your shoes for a test-jog in the aisles of the store. Don't just try them on.
• If a pair of shoes hurts in the store, they'll hurt at home. Sneakers shouldn't require a "break-in" period.
• However: Give your feet time to adjust to the new shoes. Walk around casually for a couple of days before working out.
• Don't run a big race in brand-new shoes!  

Now that you know how to find the best-fitting shoes, browse Lenny's selection of athletic shoes by New Balance, Brooks, Saucony and more!  

Lenny's thanks New Balance for contributing to this article. For more information on New Balance, visit www.newbalance.com.