# Comparison of Countermovement and Preferred-Style Jump Biomechanics in Male Basketball Players
## 1 Introduction  
The countermovement jump (CMJ) is often used to assess maximal neuromuscular performance of the lower body muscles [1, 2]. Although CMJ jump height provides arguably the most direct measure of neuromuscular performance, researchers often expand CMJ performance analysis and examine a variety of additional variables from more advanced biomechanical technologies, which are thought to provide added insight about neuromuscular strategies during maximal effort CMJ [3, 4, 5]. For example, biomechanical studies often use force plate and motion capture data to calculate and investigate joint-level mechanics in relation to CMJ performance [6]. Some of these studies identified joint- or muscle- specific CMJ strategies that were useful for the exercise selection process for polymetric and resistance training sessions [7, 8, 9]. In addition, other studies identified subject-specific CMJ strategies, which in turn provided information about how athletes individualize joint-specific strategies in relation to CMJ performance [10, 11]. Despite several positive qualities, the ecological validity of the CMJ in the context of neuromuscular assessment and monitoring is sometimes ignored in the scientific literature. This problem is perhaps best illustrated by the procedures that are used to administerthe CMJ test, which is typically performed in a highly controlled laboratory setting with standardized procedures that constrain athletes into prescribed movement patterns [10; 11]. For example, CMJ are often performed bi-laterally and with hands placed on the hips (i.e., without arm swing). While these constraints could in some instances be considered useful (e.g., isolating body neuromuscular performance), they may also inadvertently impose artificial constraints on athletes that limit them from using their preferred movement strategy (or solution) [12; 13; 14]. The pragmatic implications of such limitations are important in that CMJ performance etc. may not reflect an athlete's neuromuscular capacities or movement strategies within the context of their sport [8]. Several researchers have studied biomechanical or performance differences between different types of vertical jump tests [15; 16; 17; 18; 19]. For example, [PERSON] and colleagues [18] compared jump performance and joint kinematics between volleyball spike jumps and CMJ and found that the jump heights of both types of jumps were correlated with each other. The authors suggested that spike jump performance is influenced by general jumping ability and the standard jumping tests could be a useful part of a volleyball-specific test battery [18]. In contrast, [PERSON] et al. [17] found no correlations between jump performance of a soccer-specific jump and the CMJ, and therefore suggested that each test assesses different leg qualities and that practitioners should therefore be careful in using them to assess and monitor lower body performance [17]. Similarly, [PERSON] et al. [15] and [PERSON] et al. [16] found that CMJ performance did correlate well with basketball specific jump performance and suggested that they represent different physical capacities. It should be noted, however, that none of these previous studies investigated differences or correlations in joint kinetics. It thus remains to be determined if differences in jump performance between various jump types also reflect differences in movement strategies. The goal of the current study was to expand upon previous research into performance differences among different types of jumps with a special focus on investigating subject-preferred jump types in relation to standard CMJ and on elucidating the joint-kinetic contributions that differentiate between them. Therefore, the purpose of this study was to investigate and compare the biomechanics of CMJ and preferred-style (Pref) jumps in a group of male collegiate basketball players.