Ergojump Bosco system vs. Optojump by Microgate: two instruments to test jumping ability - Cherubini, D.; Baggion, M.; Lauriola, M.; Soraci, M. (Book of abstracts of the 6th annual congress of the European College of Sport Science, 15th congress of the German Society of Sport Science. Cologne, 24-28 July 2001, 2001)