# Biomechanics of Table Tennis: A Systematic Scoping Review of Playing Levels and Maneuvers
## 3 Results
### Lower Limb Biomechanics  
Four included studies investigated different footwork targeting side versus cross-step [4], long versus short chasse step [48], stepping directions and friction [27], and squatting [30], as shown in Tables 1 and 4, while one study compared players of different levels performing a cross-step [34]. [PERSON] et al. [4] identified that both side-step and cross-step footwork produced significantly higher ground reaction force, knee flexion angle, knee moment, ankle inversion and moment compared with one-step footwork, in addition to a significant higher peak pressure on the total foot, toe, first, second and fifth metatarsal regions. On the other hand, long and short chasse steps during a forehand topspin stroke were compared [48]. Long chasse steps produced an earlier muscle activation for vastus medialis, quicker angular velocity, and larger ankle and hip transverse RoM, whereas larger ankle coronal RoM and hip sagittal RoM compared with the short chasse steps [48]. A stable lower limb support base is another important attribute to tackle serve. [PERSON] et al. [30] compared a squat serve with stand serve and found that squat serve produced larger angles and velocities of hip flexion, adduction, knee flexion, and external rotation and ankle dorsiflexion, whereas standing serve produced a higher force-time integral in the rearfoot region. Different stepping angle and footwear friction could also influence the center of mass and kinematics of knee joint, respectively [27]. Different footwork imposed different lower limb kinematics requirements for table tennis players. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Author (Year)** & **Variant (s)** & **Maneuvers/Conditions** & **Type of Parameters** \\ \hline \hline \multirow{8}{*}{[PERSON] and [PERSON] (2017) [1]} & & Handwork: & \\  & & 1. Forehand crossourt topspin & \\  & & 2. Backhand crossourt topspin & \\  & & Handwork power and serve: & \\  & & & \\ \cl  
Comparing the lower limb biomechanics among players with various playing levels, [PERSON] et al. [28] and [PERSON] et al. [29] reported distinct findings for respective forehand and backhand crosscourt loops. When executing forehand topspin loop, higher-level players increased knee external rotation, hip flexion and decreased ankle dorsiflexion during backward end phase, and increased hip extension and internal rotation, decreased ankle and knee internal rotation during forward end phase. There was an overall increase in the ankle sagittal RoM as well as hip sagittal and coronal RoM [28]. When performing backhand crosscourt loop against backspin ball, higher-level players increased ankle dorsiflexion, version and external rotation, increased knee flexion and abduction and increased hip flexion, adduction, and external rotation at the beginning of backswing, as well as increased ankle dorsiflexion, knee flexion, reduced hip flexion but increased abduction at the end of swing [29]. During cross-step footwork, higher-level players executed superior foot motor control, as indicated by a smaller RoM of foot joints and higher relative load on the plantar toes, lateral forefoot and rearfoot regions [34]. They also demonstrated smaller forefoot plantar flexion and abduction during cross-step end phase but