I used to do all my runs with trainers (kinvara 6) and I remember they felt light and fast. a year ago I started using typeA which is way lighter, and I got used to it. Because the impacts on the road with the type A are very strong, today I did a 4 mile fast run with kinvara 9, and it felt so heavy like I have bricks for soles. Did anyone experience this? Getting used to flats and then being unable to go back to trainers for quality sessions?