PUBLISHED 05/13/2008
SHOE-PEDIA
Sockliner \'sak-'l-n r\ n
Since shoes are mass-produced to fit a wide variety of foot shapes, manufacturers use these removable foam footbeds to cover the seams and gaps in a shoe's construction, conforming it more comfortably to the bottom of your feet. There isn't much to most sockliners, so if you're looking for ways to improve your shoe's fit, you might consider replacing them with a more substantial footbed. Before you do this, however, make sure your running shoe provides the essential support, cushioning, and fit you need, since no other element is going to add what isn't there to begin with.
1. Improved Fit
Some narrow feet can benefit from an additional cushioned insole under the sockliner that raises the foot to provide a snugger fit. Conversely, a flatter footbed from another pair of running shoes can provide wide feet with a little more room.
2. More Cushioning
If you've found a great fit but you're looking for a softer feel, try a pair of flexible insoles, such as Sorbothane's Ultrasole or Spenco's Cross Trainer. Just be sure to have the salesperson check the fit to make sure the insole won't affect your stride in any way.
3. More Stability
Replacing the sockliner with a supportive footbed will reduce the collapsing of the arch that leads to muscle fatigue and running inefficiency. For reviews of eight of the latest supportive footbeds for men and women, go to runnersworld.com/footbeds.
4. Corrective Aid
Doctor-prescribed foot-beds, or orthotics, don't always extend all the way to the toes so that they can be used in a variety of shoes. Cutting a sockliner so that it fits flush against the front of an orthotic can improve the fit and reduce the chance of blisters.
Decoupled Heel \d-'k -p ld 'hl\ n
This split design in the heel works like a car's independent suspension to isolate the initial strike zone at the back of the shoe from the rest of the sole unit. This design improves a shoe's shock absorption capabilities by reducing the impact forces traveling from the heel to the rest of the outsole and midsole. The latest running shoes achieve this function by using columnlike pods in the heel to act as individual shock absorbers. Since 80 percent of runners land on their heels first, decoupled heels have become a popular way to enhance a shoe's cushioning.
Outsole \'aut-'sl\ n
As the shoe's bottommost surface, the outsole supplies traction and durability. Outsole designs vary greatly, but they are commonly constructed from carbon rubber, the same material used in car tires. Shoemakers also commonly use blown rubber (rubber that contains more air) in the forefoot of outsoles because it provides better cushioning at the expense of some durability. Since it's the initial point of impact, the outsole often includes features like decoupled heels and footbridges that assist in the overall cushioning and support. Every running-shoe outsole functions in a similar way yet looks a little different because most manufacturers have a signature tread pattern in each line of shoes.
Footbridge \'fut-'brij\ n
A reinforced platform under the arch between the heel and the sole that prevents the shoe from bending in the middle. The footbridge, or shank, supports the foot between the heel of the shoe and the forefoot and supplies torsional rigidity to prevent the shoe from twisting easily under landing pressure (excessive twisting can lead to runner's knee and other joint alignment injuries). To test the torsional rigidity of a running shoe, hold it at the heel and toe with both hands and try to twist the sole from side to side in opposite directions. The harder it is to twist the shoe in the middle, the more stable its foundation and the better the torsional rigidity.
Treads \'tredz\ n
Treads are the part of the outsole that comes in direct contact with the ground. On road-running shoes, treads supply cushioning while giving the shoe a bit of added traction. Runners often refer to these small raised treads as waffles (at right, top), in reference to the first popular Nike outsole created by Bill Bowerman with the help of his wife's waffle iron. On trail shoes, where traction is more important than cushioning, the raised treads are called lugs. Lugs are often deeper, with straight edges rather than the more rounded edges found on road shoes. These may be molded as an integral part of the outsole or encapsulated in another material to form a separate unit.
Runnersworld.com Your perfect shoe is a click away
Watch videos of the award-winning shoes in this guide at runnersworld.com/awards.
Find a specialty running-shoe retailer in your area at runnersworld.com/storefinder.
Determine your foot type at runnersworld.com/wettest.
Search our archives of running-shoe reviews at runnersworld.com/shoefinder.
