## 1 Introduction  
It is widely known that physical activity (PA) provides numerous benefits for the physical, psychological, social and cognitive health of children and adolescents. Moreover, moderate-to-vigorous physical activity (MVPA) is favorably associated with health indicators, such as cardiovascular health, body composition, mental well-being and metabolic function [1]. Despite this, more than 80% of adolescents aged 11 to 17 do not meet the current PA recommendations of the World Health Organization (WHO), which suggest at least 60 min of moderate to vigorous physical activity per day; even worse, girls are more inactive than boys, compromising their current and future health [2]. According to these authors [2], changing adolescents' behavior regarding PA is a challenge, particularly in light of the low overall rates of activity among this population. Similar results have recently been obtained from the Global Matrix 4.0 Report on PA for Children and Youth, which establishes that only between 27% and 33% of young people achieve the recommended amount of daily PA [3]. For this reason, in 2018, an action plan on PA was launched and the 194 Member States of the WHO agreed to reduce the global prevalence of physical inactivity in young people by 15% by 2030 [4]. In addition, new public health recommendations were established for children and adolescents aiming to accumulate at least 60 min of moderate to vigorous PA daily, as well as muscle-strengthening activities at least 3 days a week [5]. According to these guidelines, the amount and intensity of different types of PA such as aerobic and muscle and bone strengthening are associated with better health parameters. Within this field, two predominant modalities of physical exercise (strength and endurance training) have attracted considerable scientific interest due to their distinct physiological mechanisms and cognitive outcomes. Although both exercise modalities contribute to overall physical fitness, they engage disparate biological pathways and elicit differential effects, thereby justifying a rigorous comparative analysis. Consequently, public health entities prioritize health improvement initiatives due to the widespread sedentary lifestyles observed globally among both adult and youth populations [4]. Physical fitness has been unequivocally identified as a critical determinant of overall health [6] playing a vital role in numerous everyday activities, many of which involve physical exercise and health maintenance. Among adolescents, physical fitness levels are notably below desired standards and have been declining significantly over recent decades, representing a global issue. Approximately 46% of female adolescents and 33% of male adolescents are affected by insufficient physical fitness levels [7]. In this respect, the reduction in PA among adolescents is particularly concerning, as high fitness levels during this developmental stage are closely linked to a better quality of life and mental health [8]. Endurance training, particularly through aerobic exercise, has been extensively documented for its positive effects on cognitive function. Aerobic exercise has consistently been shown to enhance executive functions, including working memory, cognitive flexibility and attentional control [9; 10; 11]. Of particular note, high-intensity interval training (HIIT), a specialized form of endurance exercise, has demonstrated superior efficacy in enhancing cognitive flexibility and processing speed compared to continuous aerobic exercise [12; 13]. These cognitive enhancements are frequently attributed to mechanisms such as increased cerebral perfusion and the upregulation of neurotrophic factors, which are critical for synaptic plasticity and overall brain function [14; 15]. Conversely, strength training, historically regarded primarily for its physical benefits, is increasingly recognized as a significant contributor to cognitive health.