Author(s): LIU, C., ZHANG, B., GAO, Y., Institution: MINZU UNIVERSITY OF CHINA, Country: CHINA, Abstract-ID: 1202

INTRODUCTION:
Techniques and tactics, holding fundamental positions in tennis, are the dominant factors in competitive performance and significantly influence players’ performances and match results. Prior studies mostly focused on hard courts without considering venue effects and remained at the descriptive and comparative levels, with relatively lacking of specialized and targeted research on shot placements by using complex mathematical models. This study integrates venue factors from shot placements and studies the evaluation metrics of techniques and tactics. After formulating the evaluation criterion of shot placements in different types of courts, this study determines and analyses the impact of shot placements scoring rates in different types of courts on match results, which is valuable and innovative.
METHODS:
The Percentile Method is used to formulate evaluation criteria and the Grey Relational Grade(GRG) assesses the correlation between the scoring rates of shot placements and the total scoring rates. By ranking the impact of each tactical and technical metrics on scoring and losing points, this study determines the influence of metrics from shot placements scoring rates on match results.
Recorded game videos includes 70 hard-court matches (2,520 games, 14,480 points), 70 clay-court matches (2,180 games, 13,252 points), and 70 grass-court matches (2,512 games, 14,022 points). Six metrics of shot placements include forehand straight(FH-ST), backhand straight(BH-ST), forehand diagonal(FH-DL), backhand diagonal(BH-DL), forehand side(FH-S), and backhand side(BH-S). All data observation, statistical analysis, and data entry were independently conducted by the researcher. To validate inter-rater reliability, 10 recorded game videos were randomly selected by a master’s student specializing in tennis for parallel observation and analysis. The Kappa coefficient between the two datasets reached 0.92, indicating high consistency and suitability for research.
RESULTS:
Scoring rate evaluation criteria for shot placements formulated by the Percentile Method are court-specific. On hard courts, the correlation between the scoring rates of shot placements and the total scoring rates are ranked as follows: FH-DL, BH-ST, BH-DL, FH-ST, FH-S and BH-S, with coefficients of 0.884, 0.872, 0.853, 0.848, 0.791, and 0.743. On clay courts, the order is BH-DL, FH-DL, BH-S, BH-ST, FH-ST and BH-S, with coefficients of 0.879, 0.875, 0.861, 0.857, 0.848, and 0.718. On grass courts, the sequence is FH-DL, BH-DL, FH-ST, BH-ST, FH-S and BH-S, with coefficients of 0.849, 0.826, 0.808, 0.803, 0.780, and 0.666.
CONCLUSION:
Evaluation criteria for shot placements on hard, grass, and clay courts enrich the tennis technical-tactical metrics system. The ranking of evaluation metrics for shot placements on hard courts, from highest to lowest, is: FH-DL, BH-ST, BH-DL, FH-ST, FH-S, and BH-S. On clay courts, is: BH-DL, FH-DL, FH-S, BH-ST, FH-ST, and BH-S. For grass courts, is: FH-DL, BH-DL, FH-ST, BH-ST, FH-S, and BH-S.