Intense competition period impacts on heart rate variability in 8 elite swimmers - Hellard, P.; Caudal, N.; Nanoorenberg, P.; Schmitt, L.; Lacoste, L.; Cervetti, J. P.; Rey, J. L.; Fauquet, C. (Book of Abstracts - 9th Annual Congress European College of Sport Science, July 3-6, 2004, Clermont-Ferrand, France, 2004)