In basketball, fast-break and early-offense are called “progressive plays" because the ball is continuously advanced from the back-court through the front-court to the basket. In a progressive play, the preceding play and situation are related to the subsequent play and situation. The plays are not necessarily chosen freely due to the former play or situation. Plays and situations that are related to each other and are frequently performed in sequence are referred to as nagare in Japanese. This study aimed to extract the factors of nagare in a fast-break-aiming play with statistical procedures. We observed and evaluated 658 plays considered either fast-break or early-offense plays. These plays took place during 12 games between the RF team and 6 other teams in the same bj League (Japanese Professional Basketball League) held in 2009 and 2010. A total of 17 items such as “How the opponent's ball was taken away," “The number of defensive players putting pressure on the ball man when taking the ball," “Distance (length) from the end line to the place where the ball was taken away," and so on were assessed. As categorical and continuous scales were mixed in the data, a correlation matrix was computed using Pearson's correlation coefficient, a contingency coefficient, and a correlation ratio, respectively. The correlation matrix was factored by principal factor solution and orthogonal normal varimax rotation.
As a result, the following four nagare factors explained 61.2% of the total variance: (1) the nagare factor deciding the offensive play pattern in the front-court depending on the speed of conveying the ball in the back-court, (2) the nagare factor deciding the ball-conveying situation and the success of the fast-break depending on the ball-taking situation, (3) the nagare factor deciding the speed of conveying the ball in the back-court depending on the number of offensive players, and (4) the nagare factor deciding the success of shooting depending on ball-taking area, play after ball-taking, and shooting area.
After removing spurious correlations using a partial correlation, five paths with substantial significant correlations were found as follows:
(1) “How the opponent's ball was taken away" → “The difference in the number of offensive and defensive players when the ball went through the center line" → “Whether the fast-break was successful or not";
(2) “Distance (length) from the end line to the place where the ball was taken away" → “The difference in the number of offensive and defensive players when the ball went through the center line" → “Whether the fast-break was successful or not";
(3) “The number of defensive players putting pressure on the ball man when taking the ball" → “The difference in the number of offensive and defensive players when the ball went through the center line" → “Whether the fast-break was successful or not";
(4) “Distance (length) from the end line to the place where the ball was taken away" → “The number of players conveying the ball" → “Whether the fast-break was successful or not"; and
(5) “Distance (width) from the side line to the place where the ball was taken away" → “The play just after the ball was taken away" → “The shooting area" → “Whether the shooting was successful or not."
