The role and development of sprinting speed in soccer

Doctoral thesis, Faculty of health and sport science, University of Agder 2014Purpose: The overall objective of this thesis was to investigate the role and development of sprinting speed in soccer. Six original studies plus a published review have been completed towards with this objective. Valid and reliable measurement of sprint times is a prerequisite to reliably detect true changes in sprinting performance. Therefore, the purpose of study I was to quantify potential sprint time differences between single beamed (SB) and dual beamed (DB) timing systems. The aim of study II was to compare different sprint start positions and generate correction factors between popular timing triggering methods on 40 m sprint. The results from these two methodological studies secured a fundamental platform for interpretation of further sprint data in the thesis. The purpose of studies III and IV was to use a large database of soccer athlete sprint and countermovement jump (CMJ) tests collected under highly standardized conditions over 15 years to estimate generalizable differences in sprinting speed and jumping height as a function of: 1) athlete playing level, 2) field position, and 3) age. Additionally, we also evaluated the evolution of sprint and CMJ ability among male professionals and female elite players in Norwegian soccer over a 15 year period. The purpose of study VI was to investigate the effect of training at 90% sprint speed on maximal and repeated sprinting performance in soccer. The aim of study VII was two fold: 1) To compare the effects of training at 90 and 100% sprint speed on maximal and repeated sprint performance, and 2) to compare the effects of directly supervised sprint training versus unsupervised training on maximal and repeated sprint performance