HIIT Training: High-Intensity Interval Training
Nowadays, high-Intensity Interval Training (HIIT Training) is viewed as one of the most effective ways of improving the endurance capacity of the players.
After the summer break, and the corresponding decrements in physical fitness, the preparation period focuses on restoring the physical fitness of the players. The endurance capacity of the players is one of the factors that is reduced in the summer break. However, this capacity is also of importance for delivering a high workload throughout the whole match. But why is endurance so important for performance in team sports and how can you improve endurance? In this blog we will try to find answers to these questions.
The endurance capacity is related to the ability of the body to take up (and use) oxygen. This capacity of the players is heavily stressed during a match: the average heart rate throughout a match is 80-90% of the maximal heart rate(1). One of the factors contributing to this reliance on endurance capacity is the occurrence of repeated sprints in a match. But how does endurance capacity contribute to the ability to perform repeated sprints? Most people think that oxygen only plays a role in the production of energy during sprint actions. However, oxygen also plays a crucial role in recovering from these actions. When performing repeated sprints, the time between these sprints is used to recover from the previous action (i.e. removing by-products of energy production and thus restoring the balance). Since oxygen plays a vital role in this process, decreased oxygen availability will result in reduced recovery. When this incomplete recovery is repeated over and over during a match, the equilibrium in the body gets worse and worse, which in turn leads to the symptoms of fatigue during and towards the end of the match.
Now that we have seen how the endurance capacity contributes to the repeated sprint ability, we also know why the performance of the players is reduced after the summer break. Thus, one of the focus points during the pre-season period should be to improve this capacity. For which it is known that training at intensities >90% of the maximal heart rate will improve the endurance capacity(2). However, this does not mean that your whole training session needs to be at this intensity. Only 6-8% of your total training time needs to be in this range to improve the physical fitness of your players(2).
However, how can you make sure that your players reach the intended intensity? An effective, and time-efficient, way would be to integrate a high-intensity interval training (e.g. 4 x 4min at 12-14km/h with 3 min rest). To make the exercises more sport specific (and more fun), you can also integrate game formats. Game formats with a small number of players (i.e. 1v1 or 3v3) are most suited to reach the intended intensity(3). However, game formats with more number of players and larger relative playing areas (i.e. 5v5 with field dimensions of 40x35m) are also suited to reach the intended intensity. Examples of suitable game formats are shown in table 1(3).
Endurance capacity plays a large role in the ability of the players to deliver a high workload throughout the entire match. Since this capacity is decreased during the off-season, it is important to restore this capacity in the pre-season period. One of the ways to do this is to integrate a high-intensity interval training. Since these type of exercises are not sport-specific, game formats with a small number of players (1v1 or 3v3) or game formats with more number of players but a larger relative playing area (e.g. 5v5 on a 40x35m field) are also suitable for improving the endurance capacity.
In addition to changing the number of players and/or field dimensions, the work and rest duration of an exercise also influence the intensity of an exercise. To reach a high intensity the work periods should be 3-4 minutes, with a similar rest period (but preferably shorter).