Guide Rating - 
The Bottom Line
I think you’d be better off buying a new pair of shoes than buying a pair of insoles. But if you are determined to buy new insoles for your running shoes, the Spenco PolySorb Total Support Premium Insoles are a good choice for extreme overpronators.
Pros
- Maximum support
- One-year guarantee
Cons
- Not for all foot types
- Time consuming to custom fit them to your feet
- Could ruin your running shoes when you remove old insoles
Description
- 3-pod cushioning system to help prevent overpronation
- Low friction top cloth with odor control
- Heat moldable layer allows for custom fit
- Forefoot crash pad and reverse Morton’s extension for better toe-off support
- PolySorb support cradle for added arch support
Guide Review - Spenco PolySorb Total Support Premium Insoles
Though I'm not a particular fan of putting insoles into running shoes--I am sure to buy the right running shoes to begin with and replace them when the cushioning breaks down--they are quite popular amongst many runners looking to extend the life of their sneakers or prevent injury.
If you're interested in buying, here's what you should know:
This insole can be molded to your feet for a custom fit, which is great--I just wish it was less of a hassle to do. It works to correct overpronation; you can add these insoles to old or unsupportive shoes to prevent injuries caused by overpronation. However, if you only overpronate a little or not at all, this insole will cause more damage than good.
I find that they work against good running form. They have a special toe-off extension to give “greater propulsion,” which I find makes it easier for you to run on your toes instead of putting your foot down properly. Running like that can cause shin splints, calf cramps and even fractures in your foot and shin.