Performance, Training and Lifestyle Parameters of Marathon Runners Aged 20–80 Years: Results of the PACE-study - Leyk, D.; Erley, O.; Gorges, W.; Ridder, D.; Rüther, T.; Wunderlich, M.; Sievert, A.; Essfeld, D.; Piekarski, C.; Erren, T. (International Journal of Sports Medicine, 2009)