I have been a runner for over 45 years and the same problem happens to running shoes (sneakers) as well,the 'rubber' material continues to cure / harden over times. So when someone tells me their knees hurt when running I ask 'how old are you running shoes'. if older than 1 year, just toss them out. Lastly running shoes are good up to about 500 miles at most, after that they are good for mucking about. This will also apply to Boat shoes as well.

PS. I go thru 3 to 5 pair of running shoes a year, at $90 a pop, that also add up quickly.