# Predictors of Speed and Agility in Youth Male Basketball Players
## 1 Introduction  
Basketball is a dynamic and complex aerobic game that involves frequent interchange of high-intensity anaerobic activities such as jumping, accelerations and decelerations, changes of direction (COD), and sprinting [1]. Besides the player's technical skills, performance and success are related to lower-body physical components of multidirectional running, power, vertical jump, and agility [2; 3; 4].  
Special research interest is directed towards physical fitness and its relation with high performance in young basketball players. In fact, speed, agility, and power are the most performance-related, evaluated, and tested abilities in basketball and tend to peak with attaining body height peak velocity (between 13 and 15 years of age) in male basketball players [5].  
A well-known fact is that significant relations exist between jump performance, running speed, and agility in basketball players [3; 4; 6; 7; 8]. The aforementioned physical components have been shown to vary by gender and age [9], especially from 12-14 years ofage [10]. [PERSON] and [PERSON] (2003) reported that speed tends to be similar in the 11-13 age group but disparate for 15-17-year-olds [11]. Additionally, 14-year-olds have better speed and agility performance when compared to 12-year-olds [10]. How speed and agility in young players are affected by intense changes in the morphological structure that occur from 12 to 16 years [12] and which differences are present among age groups remain unclear. Such differences probably emerge due to morphological diversity in the muscle mass as well as muscle structure and differences in muscle fiber types. Variation in speed and agility is also affected by puberty, adolescent growth spurts, relative age, and maturation level [13; 14; 15].  
The selection of highly talented basketball players is usually performed by anthropometric screening, emphasizing stature. Even though height is genetically predetermined, general and sports-specific fitness tests such as 5m, 10m and 20-meter sprint, countermovement jump (CMJ), drop jump (DJ), squat jump (SJ), as well as agility \(t\)-test, and Lane test are most commonly used for the assessment of players' physical potential related to basketball success [10; 16], independent of training status and experience. As suggested by [PERSON] et al. (2019), drafted NBA players outperformed undrafted players in body height, arm span, vertical jumps, and agility [17]. This is of special importance in relation to the player's position. Body dimensions such as height, limb length, body fat percentage, and BMI have a consequential influence on running speed, explosive strength, and agility [3; 4; 9; 18; 19; 20]. Body fat percentage has been negatively associated with explosive actions, change of direction, and vertical jumps [21; 22].  
The available literature focusing on correlations between anthropometric assessment and physical performance in elite youth basketball players is highly limited. Moreover, it is important to comparatively analyze these relations in basketball players with different levels of play in order to accurately predict the lacking components to be improved in a player, thus enhancing the sport performance as well as facilitating early return to sports in case of an injury. Therefore, the aim of this research was to identify the anthropometric factors predicting speed and agility profiling in under 14 (U14), under 15 (U15), and under 16 (U16) basketball players. In addition, we aimed to investigate the correlation of physical performance tests with the players' anthropometric profiles. We hypothesize that a superior lower body explosive strength (CMJ, DJ) performance would be associated with a shorter sprint times and change of direction test times.