The contribution ratios of a number of biomechanical variables to the speed of motor response and the accuracy of performing the forehand ground stroke skill for squash players The effect of physical activity

Abstract
The aim of this research was to: Develop an electronic test to measure the accuracy of the forehand groundstrokes of advanced squash players by designing an electronic device. It was also to identify the values ​​of motor response speed and accuracy of the forehand groundstrokes of advanced squash players. It was also to identify the proportions of biomechanical variables contributing to motor response speed and accuracy of the forehand groundstrokes of squash players. The researchers assumed that there are percentages of contribution of biomechanical variables to the speed of motor response with the accuracy of performance of the straight forehand ground stroke skill for squash players. The researchers used the descriptive approach for its suitability and the nature of the research. The research sample included national team players and advanced club players in the game of squash, numbering (30) players representing five clubs. The researchers used the descriptive approach for its suitability to the nature of the research. The research sample included the national team players and advanced club players in squash, numbering (30) players representing five clubs. Tests, measurements, technical scientific observation, and biomechanical analysis were used as means of collecting data. An electronic test was designed to measure the accuracy of the forward straight ground stroke. To achieve the scientific and technical observation, the researchers used (3) iPhone cameras at a speed of (240) images per second, and the (Kenova) analysis program was used to obtain the mechanical variables, and the following statistical methods were used (standard deviation, (T) test for related samples, Pearson correlation coefficient, multiple regression coefficient, (Shapiro-wilk) test). The data were processed using the statistical package (SPSS). The most important results reached by the researchers were:
1. Both the height of the body's center of gravity and the angle of the trunk had a highly significant effect on the speed of motor response and the extent of their contribution to the accuracy of the forward straight ground strike in the main position. 2- The variables of torso angle and racket inclination had significant contributions to the change in motor response speed and accuracy of the forehand groundstroke during the ball-striking phase.