# Technique Variables Associated with Fast Bowling Performance: A Systematic-Narrative Review
## 1 Introduction  
Fast bowling is a highly individualistic and specialised skill within the game of cricket. Bowling strategy is devised to restrict runs by either reducing scoring opportunities or achieving a dismissal. Fast bowlers aim to achieve these outcomes by using strategies such as generating high ball release speed, accuracy and deception [1]. The most widely researched strategy is maximising ball release speed (BRS), where bowlers have been reported to bowl in excess of 40 m/s (90 mph) [2]. High BRS reduces the batter's reaction time and may hamper the ability to interpret the delivery, resulting in poor shot selection and execution [2]. To achieve these high speeds, the bowler completes a run-up to the crease before a leap into the delivery stride [2; 3; 4; 5]. Mechanically, the technique then involves efficiently converting some of the whole-body linear momentum generated during the run-up into angular momentum which is sequentially transferred in a proximal to distal sequence from the torso, down the arm and into the bowling hand, eventually resulting in a high tangential release velocity of the ball (BRS) [2; 6].  
While the ability to generate high BRS is a major characteristic in defining a successful fast bowler, bowling accuracy [1; 7] and consistency [1] are also important. Bowling accurately and consistency in combination with a well-placed field can restrict the opportunity for scoring runs and place a batter under stress [1]. Additionally, lateral variation of ball flight trajectory through movement in the air (swing) or movement off the pitch (seam), along with changes in pitch length, pitch line and ball speed, are strategies fast bowlers may use to create uncertainty for the batter. This, when coupled with speed and accuracy, often challenges the batter's shot selection [5]. However, the majority of research in fast bowling has focused on BRS, with limited research exploring the biomechanics associated with these other bowling strategies.  
Several studies have researched various combinations of biomechanical variables with the aim of developing a mechanical understanding of how fast bowling techniques are associated with BRS [2; 8; 9; 10; 11; 12]. These variables may vary between individual bowlers due to differences in morphology and physical characteristics [13]. The majority of these studies have explored time-discrete kinematic and kinetic variables at specific time points, such as back foot contact (BFC), front foot contact (FFC) and ball release (BR), with inferences that are a generic representation of the cohort studied [2; 3; 10; 12].  
There have been contrasting findings in studies linking bowling technique to BRS. For instance, while [PERSON] et al. [3] found controlled rear leg knee flexion for just post half the delivery stride phase to be associated with BRS, [PERSON] et al. [10] found no correlation between these two variables. Moreover, the proposed role of the rear knee during the delivery stride is different across studies [3], and even within cohorts in the same study [10]. Consequently, the ambiguity of findings in the current literature provides a challenge in translating fast bowling performance research into applied practice.  
Principally, there is a need to distil and synthesise the literature to establish variables that are consistently and accurately associated with enhancing fast bowling performance. Hence, the objective of the review is to present a comprehensive, critical and objective analysis of the biomechanical characteristics that have been associated with fast bowling performance in the literature. It aims to provide coaches with evidence-based insights into the technique variables that are critical for optimising fast bowling performance, thereby informing training strategies.