Hartmann competed as a triathlete, but had to give up elite sport in 1991 after shattering his hip in a training accident. He qualified as a physical therapist while on an athletics scholarship in America and later came home and set up a clinic above the family jewellery business in Patrick Street, Limerick. In May 2007 he moved his two-man clinic to a new location in the University of Limerick's sport complex. Hartmann's healing powers are world-renowned after successfully treating track and field athletes like Paula Radcliffe, Sonia O'Sullivan, Kelly Holmes and Colin Jackson and a plethora of African distance stars from Kenya's Moses Kiptanui to Ethiopia's Tirunesh Dibaba. His fees are higher than most physios, but he provides a much different service. Hartmann prefers to treat only two to three athletes a-day and spends several hours with them per session. He is a strong proponent of 'pre-hab' and injury-prevention by strengthening 'core' muscles and stretching. Hartmann takes a very holistic approach, believing the mind is as important as the body for healing. Paula Radcliffe said: "I believe he has a special gift," but Hartmann himself said "it is a nice idea, but I don't believe I have healing hands or any kind of special powers."