# Biomechanics of Table Tennis: A Systematic Scoping Review of Playing Levels and Maneuvers
## 1 Introduction  
Table tennis is a competitive sport which requires technical preparation, tactics, as well as mental and motor training [1]. Players with higher technical capability demonstrate good coordinated movement with controlled strike power, which yield adequate speed and spin on the ball in limited decision time [2; 3]. To master the stroke, professional players have to rotate the trunk efficiently and place excellent foot drive in response to various ball conditions [2]. Whole-body coordination plays an important role in table tennis, as the biomechanics of lower extremities is closely related to the upper limb performance [4]. An incorrect technique would alter movement mechanics and thus joint loadings that are related to risk potential of injury. A retrospective study found that about one-fifth of table tennis players suffered from shoulder injuries [5]. Although numerous studies had investigated the biomechanics of table tennis maneuvers, their methods and protocols were generally inconsistent.  
Therefore, direct comparison across studies is not feasible. Furthermore, players of different skill levels may perform different table tennis maneuvers with unique techniques and patterns. To identify the common characteristics of higher-level players, an investigation has to be conducted properly mapping playing levels with different maneuvers. Such information can help in designing sport-specific training programs in table tennis.  
Biomechanical reviews of various sports, such as football [6; 7], tennis [8; 9], and swimming [10; 11; 12] have identified strategies to improve sports performance and prevent injuries. While previous review articles summarized physiological demands of table tennis players [13; 14], conducted match analysis [15; 16; 17], and reviewed contemporary robot table tennis [18; 19], there have been no sufficient reviews on the biomechanics of table tennis. There was an article reviewing the science (including biomechanics) of major racket sports [20], however its focus was not on limb movements and the joint loading of different skill levels.  
A systematic scoping review accounts for the published evidence over a broad topic by summarizing, mapping, and categorizing key concepts that underpin a particular research area using a systematic protocol [21]. Such a review looks into the literature which has demonstrated high complexity and heterogeneity. The objective of this systematic scoping review was to identify recent advances in testing protocols, variables, and biomechanical outcomes regarding table tennis maneuvers and performance. The scope of sports biomechanics in table tennis is board, which has not been comprehensively reviewed. The objectives of this review were guided by the following research questions:  
1. How was the biomechanics of table tennis movements analyzed?
2. What were the biomechanical differences between higher- and lower-skilled players?
3. What were the biomechanical differences among various table tennis maneuvers?  
The principle focus or concept of this review pertained the categorization of biomechanical variables while the primary context was to summarize the playing skill levels and maneuvers. This study can contribute to the field of sports science by identifying key ideas for performance improvement and identify research gaps in table tennis.