Engaging in physical activities and warming up are essential practices for athletes, coaches, and individuals dedicated to maintaining their health [1], [2], [3], [4]. While it is commonly advised for athletes to engage in preparatory exercises or warm-ups prior to intense training sessions or competitions, recent research findings have highlighted the necessity for establishing a consensus on the optimal intensity and duration of these warm-up activities [5]. The intensity of exercise and physical activity is always considered one of the most effective factors in determining the required energy, including fat oxidation as an important energy source and using more substrate to increase individual performance [6], [7].

Studies have shown that increasing exercise intensity to a certain extent causes an increase in fat fuel consumption and muscle blood flow, subsequently increasing muscle access to fatty acids [8], [9]. The oxidation of carbohydrates significantly increases when the activity intensity in various sports, such as football, reaches a high level. During exercise, muscle glycogen, blood glucose, plasma-free fatty acids, and intramuscular triglyceride are the main energy sources [10]. The underlying cause of this phenomenon can be attributed to the upregulation of the glycolytic pathway, which hinders the translocation of elongated fatty acids into the mitochondria, consequently resulting in a reduction in fatty acid oxidation [11]. Therefore, one important factor that allows the athlete to have good abilities in different football positions is how to warm up or the appropriate intensity of warming up to enter the match to benefit from energy sources at different times properly [11], [12].

Nevertheless, it is important to note that players occupying various positions within a soccer team experience distinct levels of work pressure. Specifically, midfielders are required to cover the greatest distance during a match, often reaching 11–11.5 km. In contrast, defenders and forwards typically cover shorter distances. Goalkeepers, on the other hand, tend to cover approximately 4 km. Consequently, the metabolic demands for fat oxidation among these players also differ [13]. According to FIFA, in the 19th World Cup, Xavier Hernández from Spain ran 80.20 km in 7 games in 636 mins with an average speed of 22.07 km/h, and Maxi Milano Pereira from Uruguay ran 78.60 km in 7 games in 660 mins with an average speed of 22.02 km/h. This issue clearly explains the importance of fats as a great energy source for providing essential fatty acids, absorption of fat-soluble vitamins, ultimately delaying fatigue and increasing the athlete's ability to continue the activity, and suitable calories for long-term activities [14].

Limited research has been conducted on the oxidation of fat and carbohydrates during exhaustive physical activity. Existing evidence suggests that the incremental test performed on the treadmill elicits a greater degree of fat oxidation than the bicycle ergometer due to the greater involvement of muscle mass [15]. In general, there is an exponential increase in the relative rate of carbohydrate oxidation for energy provision [16], while the relative rate of fat oxidation for energy consumed decreases correspondingly [17]. On the other hand, the absolute amount of fat burned during physical activity increases and decreases with the intensity of the activity [18]. The process mentioned above is subject to the influence of multiple factors, including gender, personal characteristics [15], level of physical fitness [19] and the type of protocol used [15].

According to training factors, warming up effectively increases sports performance through the dynamic response of oxygen uptake during exercise [20]. Also, warming up before starting training or competition increases the rate of muscle metabolism, heat and production of CO2 and H+ [21]. Studies have shown that if the amount of muscle metabolism in warming up is low and cannot change the temperature and the amount of muscle pH, the dynamics of oxygen uptake will not be affected, and this can be a factor for the uneconomical use of muscle fuel, especially Fat sources [22]. Therefore, the intensity of warming up before the activity may be important in stimulating and using energy resources during the activity and increasing the person's efficiency in using those resources for a longer period and more intensity [23]. Therefore, the intensity of warming up before physical activity may affect stimulating and using energy resources during activity and increase the efficiency of a person in using those resources for a longer period and more intensity [24]. However, information is scarce regarding the impact of warming-up intensity on the oxidation of fat and carbohydrates and the energy expenditure of increasing activities; also, the maximal oxygen uptake (VʹO2max) is an important estimate of a person's aerobic capacity [25]. Therefore, this study aims to examine the impact of two distinct warm-up techniques on the indicators of fat and carbohydrate oxidation, total energy expenditure, heart rate, oxygen uptake andVO2max of trained football players during an exhaustive incremental exercise.