# Assessing Table Tennis Technical Proficiency in Individuals with Disabilities: A Scoping Review
## 4 Discussion
### Table Tennis Technical Proficiency Tests  
#### 4.1.1 Accuracy  
For service accuracy, [PERSON] et al. [27] developed detailed protocols for short service, extreme side service, and target service. With consideration of the type of disabilities, they set the target zones according to the player's classification as wheelchair or standing players. The authors provided very clear drawings and descriptions of the test instructions, number of attempts, and scoring methods. Similarly, [PERSON] et al. [21] also utilised a series of tests to assess the accuracy of various services (long backspin to backhand/forehand, short backspin to backhand, long no spin to body, fast ball to forehand, and long sidespin to backhand). A score of 0 to 2 was assigned depending on the service execution (wrong service/poor control/good control) and landing location of the ball (missed/poor location/good location). However, no further information was provided on what is considered good control or good location. The table tennis experience and number of raters involved in assigning the scores were not reported. Hence, it is somehow difficult to replicate these tests and to compare the results across studies. One common strength shared by all service accuracy test protocols is that no specialised equipment is required. To implement service accuracy tests; only a simple video camera or mobile phone would be sufficient to record where the ball hits the table. For service return and stroke accuracy, some tests were first developed for able-bodied players and subsequently applied to individuals with disabilities. For example, [PERSON] et al. [27] employed the forehand/backhand skill speed tests and displacement speed test previously evaluated in able-bodied players [32] with elite para-players with physical and intellectual disabilities. In these tests, table tennis balls were shot by a robot at high speed with 80 balls per minute to different locations. Players were instructed to return the shots using specific techniques (e.g., topspin forehand, topspin backhand) to designated areas across the table. Similarly, [PERSON] et al. [16] developed a comprehensive protocol comparing 16 set services of various strokes (forehand/backhand), directions of return (cross/straight), spins (topspin/backspin/right sidespin/left sidespin), and fields of return (left/right side of the table). Using a table tennis robot to deliver shots at a frequency of 1 ball every 2 s, players were instructed to return each service to a specified target (A4 paper size) on the table. From video recordings of the service return, a 7-by-7 digital frame was constructed around the target to calculate the relative error as width (left-right) and depth (forward-backward) deviations from the target. A deviation of one square in the 7-by-7 frame was counted as 1 point in the respective direction. This data analysis method allows one to quantify the magnitude and direction of the error, providing additional insights than using a simpler scoring system such as hit or miss. Lastly, [PERSON] et al. [31] used a \"Cup Ping-Pong\" protocol to assess the accuracy of throwing and catching in children with DCD. The children were instructed to throw a table tennis ball against the wall at 1 m distance and catch it in a plastic beer cup in the other hand. The number of balls caught out of 10 attempts was counted. This test is simple and easy to implement, making it a good choice for field testing. As the throwing and catching protocol only involves ball manipulation without the use of a racket, it is unclear if the scores can indicate table tennis performance or more general hand-eye coordination. Ball manipulation and hand-eye coordination are deemed relevant to table tennis because a legal serve requires players to toss the ball up for at least 16 cm (6.3 inches) before hitting the ball on its way down. If similar throw-and-catch tests are to be implemented for players with physical disabilities, some adaptations may be needed to adjust the rebound distance and how the ball is being caught.