After a 20 mile ride on my old df, my back was sore, shoulders were sore, butt was sore and hands were numb. It was very uncomfortable. Now, one week after getting my EZ Sport, all of that is gone but my knees are a little sore. Is that sort of common when just beginning to ride a bent? After 20 miles, I was still fresh and pain free except for the knees. Love this bike.