Jump as a Fatigue Indicator
The monitoring of neuromuscular fatigue in athletes is very relevant when planning training sessions and competitions.
We know that athletic performance is a complex phenomenon that depends on numerous constraints, but do we know how these constraints relate to and interact with each other? Which constraints are the best ones to intervene in? Can we prevent injuries by changing team values? As suggested in the article ‘On the relatedness of nestedness and constraints’ published in February in Sports Medicine magazine by Balagué et al., the complex dynamic systems perspective may help us answer these questions, and others.
In the complex dynamic systems approach, sports actions are understood as the result of the interaction between the athlete and his environment. If there are changes to personal constraints (e.g. motivation, fatigue, ability, etc.) and/or the environment (e.g. opponents, the behaviour of the crowd, the state of the playing field, instructions from the coach, etc.), the opportunities for action change as well. During competition, some of these opportunities for action appear and disappear very quickly. Some extremely quick, highly motivated and skillful football players, such as Leo Messi, are able to sense opportunities for action in rapidly changing environments that may go unnoticed by other players. In fact, the same objective information about the environment has a different meaning for each player.
Most highly unpredictable actions, such as nutmeg (passing the ball between the legs of a defender) emerge spontaneously, in a completely unplanned way. As Balagué notes, “Messi’s objective is not to nutmeg, but rather get past the defender in order to move closer to the opponents’ goal”. The fact that this type of action emerges spontaneously makes it impossible to plan in advance, which is especially relevant to the way training is developed and the type of instructions the coach gives to the players.
The instructions coaches give during a game or training session also include information about the environment, and as such, they do not have the same effect on all athletes. The text also warns that instructions can sometimes even be counterproductive. For example, what happens when these instructions compete with the immediate opportunities for action that emerge during the game through the interaction with the opponents? Will we avoid sending a long ball to a player who lost his marker because the coach orders short passes? This doubt could delay the player’s reaction to the pass, which could then be intercepted.
Instructions should be adjusted to the characteristics and needs of the receiver(s). They should also consider the timescale of the action that the instruction is intended to influence. In intentional processes, i.e. those that are produced on timescales that are long enough to be controlled voluntarily (such as the way a penalty shot is taken), the instructions may make sense (if the coach manages to modify the intention). However, this is not the case when the time pressure does not allow for this voluntary control (such as Messi’s dribbling skills described above).
The article proposes a different understanding of the constraints that affect the task and of the concept of the task itself, with both theoretical and practical repercussions. As the authors state, “the task is a systemic property that cannot be given without an objective; in other words, the regulations should be respected voluntarily, and the actions of the opponent must be perceived by the athlete in order to act as informational constraints”. Without this active participation of the athlete, there is no task; there is no constraint, nor can the desired results be achieved. This is well known by professionals who have made suggestions to their athletes, during training sessions or competition, which the athletes have not internalized or prioritized, and have then achieved disappointing results. In practice, this new understanding of the concept of the task reinforces the role of the athlete in the training and competition process, while simultaneously proposing a less prescriptive and more co-adaptive role for the coach.
As Balagué et al. suggest, the personal and environmental constraints that determine performance evolve on different timescales. This means that some change more slowly (e.g. personal values, somatotype or chronotype), while others change more quickly (e.g. mood, internal load or muscle strength). These constraints, regardless of their origin (physiological, psychological, biomechanical, etc.), are related to each other through these timescales. Those that change more slowly have a “constant” influence on those that change more quickly. From this perspective, they are more relevant to performance. For example, if we focus on what an athlete might values (e.g. athletic success), which can be maintained for decades, then we do so together with other constraints such as motivation, objectives, strategies, attention and the perception of opportunities for action. In turn, these more rapidly-changing constraints, which influence performance, support those that change more slowly, interacting with them through circular causation. In other words, by intervening with the perception of opportunities for action, we also influence objectives, motivation and values.
To better understand this concept, Rafel Pol gives the following example: “If a player values personal success more than team success, this will influence his decisions on the field and the techniques he develops, and this will have physiological consequences. If he values collective success over personal success, he will prioritise his intervention in actions that may not directly benefit him. However, if he prioritises immediate personal success, he will avoid intervening in these ‘altruistic’ actions and will only intervene in actions that strengthen him individually”. No matter how many instructions a player receives on the importance of helping out his teammates more in defence, and no matter how many technical exercises he performs to practice this help, if his personal values do not change, it will be very difficult to achieve the desired behaviour.
We must also remember that intervening collectively (encouraging the team to put pressure on the rival team, modifying the number of players or the dimensions of the field, etc.) will collectively constrain individual actions and their physiological consequences, making it unnecessary to develop them out of context. It is therefore vital for coaches to understand the interactions between the personal and environmental constraints that affect performance; they should recognize their hierarchical organization based on their action timescales, which will allow them to intervene with better judgment and effectiveness.
Adriana Roca Ferrandiz
Although there are several studies on this topic, many of them have analyzed these demands by looking at just a few variables or using very broad timeframes. A new study completed by physical trainers from F.C. Barcelona has analyzed several of these details more closely.
The understanding of the modifying variables of the game, based on the degrees of freedom.
Training using eccentric exercises is important to prevent possible damage. However, intensive training can also cause muscle damage, so it is critical to be vigilant in order to keep injury risk to an absolute minimum.
The importance of building a game model in football.
Cardiovascular endurance manifests as a moderator of the load result to which the athlete is exposed.