Abstract
Football is characterised by varying pace and acyclical movements that are influenced by game situations. To meet these locomotive demands in football, players need to generate energy from different sources via aerobic and anaerobic metabolism. Currently, teams are limited by small preseason windows to improve technical, tactical and physiological performances. Through the use of High Intensity Intermittent Training (HIIT), athletes may derive cardiorespiratory improvements in a short period. As such, this study aimed to determine whether HIIT could provide a practical field-based method to improve the aerobic fitness of male football players. Eighteen sub-elite football players (21 ±1.8 years, height 1.76 ± 5.7 cm, and mass 62.7 kg ± 7.2 kg), were recruited for this study. Pre- and post-experimental period, maximum oxygen uptake was measured through a modified Heck protocol test on a treadmill until volitional fatigue. A progressive overload approach was used to make the players run at intensities greater than their recorded vVO2max. Progressive overloading was implemented by increasing the vVO2max prescription percentage, along with the manipulation of the work-to-rest ratios, repetitions, sets and high-speed running total distances. The intervention was applied during the first four weeks of the pre-season, with a total of 8 specific HIIT sessions. Results obtained showed improvement in aerobic fitness metrics (pre- versus post-measurement). Specifically, statistically significant increases (p<0.0001) were noted for: VO2max (pre: 43.9 ± 4.6; post: 50.5 ± 3.4 mlO2.kg-1.mm-1); vVO2max (pre: 13.8 ± 1.5; post: 16.3 ± 1.49 km.h-1); and vVT2 (pre: 9.2 ± 1.3; post: 11.6 ± 2.0 km.h-1) as a result of the intervention. Application of the four-week intervention programme was guided by the progressive overload principle, to systematically increase the demands placed on the cardiorespiratory responses and ensure that players reach greater aerobic adaptations. Overall, the results indicate that HIIT is a time-effective training method that can efficiently improve the cardiorespiratory dynamics of football players in a limited time.