Letter by Möhlenkamp et al Regarding Articles, "Can Intensive Exercise Harm the Heart? The Benefits of Competitive Endurance Training for Cardiovascular Structure and Function" and "Can Intensive Exercise Harm the Heart? You Can Get Too Much of a Good Thing". Issue 23 (9th June 2015) - Möhlenkamp, Stefan; Heusch, Gerd; Erbel, Raimund