Model of assessment instrument for basic techniques of serving, forehand and backhand groundstroke, forehand and backhand volley based on 'acentos method' for junior tennis players in Yogyakarta region

To evaluate the basic technical skills of service, forehand groundstroke, backhand groundstroke, forehand and backhand volley, an appropriate and accurate assessment instrument is needed according to the actual tennis game situation. The purpose of this research is to develop an assessment instrument model to the 5 basic techniques based on the acentos method for junior tennis players in the Yogyakarta Region. The design to develop the assessment instrument applies the Research and Development 4D model (Define, Design, Development, and Disseminate). The approach applied was both quantitative and qualitative (mixed method). The research subjects involved 25 junior tennis players of Yogyakarta Province who were under 18 years old in Yogyakarta comprising: 15 male tennis players and 10 female tennis players. Junior tennis players used as research subjects are junior tennis players who actively participate in junior tennis matches in Yogyakarta and the National Tennis Championships. The content validity testing was based on Content Validity Ratio (CVR), while the reliability testing was based on the statistics analysis of Alpha Cronbach Consistency by using SPSS application of genova program package, while the inter-rater reliability coefficient was analyzed using ANOVA. The results showed that the assessment instrument had very good content validity, which was: 0.71-1.00 (> 0.50): 0.71-1.00 (> 0.50), the feasibility level of the assessment instrument is good, and the high inter-rater reliability coefficient = 0.866 - 0.902 (r = ≥ 0.80). In addition, the factors and indicators of assessment instruments for basic techniques of service, forehand and backhand groundstroke, forehand and backhand volley based on the acentos method were successfully developed, consist of: (1) self-confidence and mental game/psychology, (2) before executing the stroke/stage: perception and decision, (3) the execution of the stroke and the result/stage: execution and feedback, and (4) the attitude and behavior in playing tennis. Thus, it can be concluded that the assessment instrument for basic techniques of service, forehand and backhand groundstroke, forehand and backhand volley based on the acentos method can be used as an assessment instrument for basic techniques for Yogyakarta Region junior tennis players. Keywords: assessments, basic technique of tennis, acentos method