I am a fairly avid runner. I run about 60 miles a week on both trails and road. This shoe has been wonderful. I have had calf problems in the past and since starting running in this shoe I have not had a single problem with my calves. This includes at least one 14-18 mile run a week. This shoe is great for a avid runner or a casual runner. Will help you run in a more effective style and reduce injuries.