Ferrari Bravo Duccio, Rampinini Ermanno, Sassi Roberto, Bishop David, Sassi Aldo, Tibaudi Agostino, and Impellizzeri Franco M.
Soccer matches require players to repeatedly generate maximal sprints of few seconds interspersed by brief recovery periods, and several activities involving acceleration and deceleration phases. The ability to maintain high power or running speed over a series of sprints (repeated-sprint ability, RSA) has received attention from many researchers (Fitzsimons, 1993; Bishop, 2004). The aims of this study were to examine the relationship between running RSA and match physical performance, and RSA reliability, in elite soccer players. Eighteen professional soccer players were monitored with a video computerized match analysis system during two competitive seasons. From the data obtained, the total distance (TD) covered during the game and the amount of high-intensity activities (running speed above 18 km/h-1, HIA) were determined. Each season, players completed 4 times the RSA test consisting in 6x20-m+20-m shuttle run sprints with 20 s of recovery. For the correlational analysis, the highest values of TD and HIA measured during matches completed within two weeks from the RSA test were used according to Bangsbo (1994). The average time spent to complete 6 times runs and the sprint time decrement expressed as percent (%) were selected for the analysis. Reliability was determined using the typical error of measurement (TE) in 22 professional players that completed the RSA test twice within one week. TD was not significantly correlated to RSA mean time (r=0.03), while a moderate but significant correlation was found between RSA and HIA (r = -0.62; p<0.01). The TE for detecting reliability in the mean sprint time was 0.8% (95%CL, 0.6 to 1.1%), while the TE of the percent decrement was 25.0% (95%CL, 21.2 to 42.9%). This study is the first to demonstrate the ecological validity of the running RSA test for soccer players. HIA was suggested to be a better indicator of soccer match physical performance than TD. This study showed that about 40% of HIA variance was explained by RSA (the actual match performance is influenced by several factors other than physical characteristics). The most appropriate RSA index for longitudinal monitoring of athletes seems to be RSA mean sprint time (TE=0.8%) then the RSA % decrement (TE=25.0%). In conclusion, this study confirms the validity of the RSA test for soccer players.
Communication to 10th European College of Sport Science Congress