Development and validation of U15 football simulation running protocol for Young Football Players

This thesis aim is to develop and validate a U15 Football Simulation Running Protocol (U15 FSRP). Twenty participants of a football academy and sports school volunteered to participate in the study, which utilised U15 match analysis data to develop the protocol. In the study, participant absolute total distance (TD) covered in a match was 6,981 ± 1,333 m, which was divided into various activities namely, 5 ± 15 m standing, 1,659 ± 349 m walking, 2,146 ± 502.4 m low intensity running (LIR), 2,280 ± 795.1 m medium intensity running (MIR), 574 ± 157.9 m high intensity running (HIR) and 318 ± 134.3 m sprinting. It was noted that participants performed 18.9 ± 6 number of sprints (NOS) (speed ≥ 19 km.h-1) and the average distance per sprint was 16.6 ± 2.9 m. Taking into consideration the rolling substitution policy in youth football, the TD in relative values (m.min-1) were used to represent individual player TD covered. These data provided the framework to develop a running protocol that mimicked U15 match play. The protocol is thus 80 min of intermittent exercise divided by 4 x 20 min blocks of exercise with 3 x 5 min rest intervals similar to actual U15 match play duration. On every block, the running intensities were devised in a cyclical pattern required participants to run 10 repetitive cycles of LIR, MIR, HIR and walking. In every cycle, the participants alternate between Sprint and utility movements (sideways and backward running). Following the development of the U15 FSRP, its reliability and validity was assessed. The protocol sought to simulate the physical distance covered by players, percentage of time spent in each type of running intensity and the associated physiological demands (heart rate) of match play in a controlled environment. Test-retest (Trial 1 and Trial 2 separated by 7 days) was done to determine the reliability of the U15 FSRP. Variables measured were body weight (BW) loss, Borg Rating of Perceived Exertion (RPE), Felt Arousal Scale (FAS), Feeling Scale (FS), Countermovement jump (CMJ), peak sprint speed (km.h-1) and heart rate (beats.min- 1). A paired-samples t-test was conducted to assess the mean differences between Trial 1 and Trial 2. There were no statistically significant differences found between both trials (P <0.05). Reliability assessment: Pearson product movement correlation (r), Intraclass correlation (ICC) and Standard error of measurement (SEM), showed strong and good reliability (r: 0.78 to 0.97, P < 0.05, ICC: 0.84 to 0.98, P < 0.05 and SEM: ± 0.01 to ± 0.7). Validation of the U15 FSRP was done through monitoring TD, distance in each running intensities, percentage of time spent in each match activity, NOS, average distance per sprint and heart rate (HR). The U15 match and U15 FSRP results were found to be similar, and this provides sufficient evidence that the protocol measured what it is supposed to measure. Further assessment on concurrent validity showed significant positive correlation between match play and the U15 FSRP (0.48 to 0.91, P<0.05). Nevertheless, the HR was found lower in the U15 FSRP (188 ± 6.3 beats.min-1) compared to match play (207 ± 4.9 beats.min-1) which could be from the lack of actual ball play and football skills such as attacking and defending movements. This study represents the reliable and valid football simulation designed specifically for U15 football players and from a practical perspective, it has great potential for use in investigating abilities and monitoring progress of young football players.