Table 1. Measurement items of defending skills.

Defensive game performances were measured using the following 19 items: distances between attackers and defenders (8 items), angles between attackers and defenders (4 items), and the number of the players (7 items) in the tactical defending area. These items were evaluated using 5-point interval scales (Table 2). Game performances were measured using the reduced map of the pitch for the purpose of suppressing measurement error to a minimum (Suzuki and Nishijima, 2002). Basically, measurement items such as distances and angles should be evaluated using ratio scales. However, these items were actually measured using interval scales for reasons of measurement error and practicality in the context of coaching. In applying the automatic measurement method, these items could be measured directly using ratio scales.