José E. Teixeira

By José E. Teixeira, Pedro Forte, Ricardo Ferraz, Luís Branquinho, António J. Silva, Tiago M. Barbosa and António M. Monteiro

Complex and dynamic systems are characterised by emergent behaviour, self-similarity, self-organisation and a chaotic component. In team sports as football, complexity and non-linear dynamics includes understanding the mechanisms underlying human movement and collective behaviour. Linear systems approaches in this kind of sports may limit performance understanding due to the fact that small changes in the inputs may not represent proportional and quantifiable changes in the output. Thus, non-linear approaches have been applied to assess training and match outcomes in football. The increasing access to wearable and tracking technology provides large datasets, enabling the analyses of time-series related to different performance indicators such as physiological and positional parameters. However, it is important to frame the theoretical concepts, mathematical models and procedures to determine metrics with physiological and behavioural significance. Additionally, physiological and behavioural data should be considered to determine the complexity and non-linearity of the system in football. Thus, the current chapter summarises the main methodological procedures to extract positional data using non-linear analyses such as entropy scales, relative phase transforms, non-linear indexes, cross correlation, fractals and clustering methods.

Part of the book: Exercise Physiology

By Luís Branquinho, Elias de França, Pedro Miguel Forte, Adriano Titton, Felipe O. Marques, Luís Fernando Leite de Barros, Pedro Campos, Nelson Valente, José E. Teixeira, Ricardo Ferraz and Ronaldo Vagner Thomatieli dos Santos

Football has changed drastically, and currently teams can play up to 70 games in a season. This means one game, on average, every 4 days, and there is no space for pre-season. However, there may be periods of multiple games every 3 days. This congestion of games increases the incidence of injuries, which has a strong impact on the team’s success during the season. Furthermore, it is not possible to develop a methodology to achieve peak performance, but rather development and maintenance of performance. This congestion is unprecedented in football, and there is no literature describing how to manage the workload in teams with this profile. In this chapter, we will present a real case of game congestions and its associated contextual variables. We then make suggestions on how to implement resistance training with the aim of improving/or maintain performance and mitigating the incidence of injuries. This chapter presents practical examples from which coaches and physical trainers can gain insights to apply in their day-to-day professional practice.

Part of the book: Resistance Training

By Luís Branquinho, Pedro Forte, Nelson Valente, Elias de França, Tiago Venâncio, Ronaldo Thomatieli dos Santos, José E. Teixeira and Ricardo Ferraz

Children and adolescents sedentary lifestyles constitute one of the main threats to the healthy development of younger generations. This chapter critically analyzes the determinants and consequences of sedentary lifestyles in children and adolescents, highlighting the physical, cognitive, emotional, social, and economic impacts, with particular attention to trends observed after 2020. The COVID-19 pandemic acted as a catalyst for inactivity, reinforcing the digitalization of leisure habits and drastically reducing the opportunities for physical activity. However, the problem transcends the individual sphere and must be understood as a multidimensional phenomenon, shaped by family, school, community, technological, and political factors. To respond to this complexity, a multidimensional intervention model is proposed, integrating school, family, community, technology, and public policies, highlighting the need for interdisciplinary collaboration. The analysis highlights that isolated strategies are insufficient: only an integrated and sustainable response, supported by intersectoral policies, can transform the so-called “inactive generation” into a generation on the move. It is concluded that children and adolescents sedentary lifestyles should be viewed not only as a public health issue, but also as a social justice challenge, requiring the construction of environments that recognize physical activity as a fundamental right of childhood and adolescence.

Part of the book: Sedentary Lifestyle