After multiple knee surgeries on one of my knees and attempting to run distance with a lot of loss in elevation I realized that I just couldn't do it. My knees were aching and primarily from the downhill jaunts on long runs. I've been hesitant to get this shoe, but after much convincing from friends I decided to go for it. I've had them for a month now and feel so much better on runs. I've charged down hill and felt great after. The shoes make me want to run. I am happy with the purchase and excited to keep running! Just for some background on my running...I typically keep it to 5 miles a day with the occasional 15 miles thrown in there just for fun depending on time and other activities. So far so good, but they definitely run a little on the big side.