Defensive systems in basketball ball possessions

The aim of the present study was to analyse the importance of defensive systems used by winning and losing basketball teams in their ball possessions, trying to study their influence in the offensive success. To achieve this, 1450 ball possessions were registered from 8 close games (final score differences below 12 points) of the Spanish Basketball Play-offs series, from the 2004-2005 season. The ball possessions were registered by systematic observation with Cohen’s Kappa for each observational category coefficients >0.90; the variables registered were: final classification (winner and loser), type of defensive system (man-to-man half court, man-to-man pressure, zone in half court, zone pressure and mixed), points scored, number of passes and duration per ball possession. Statistical analysis used were Crosstabs commands, nonparametric χ2 (chi-square) test and a Student t-test for independent samples. The results showed these main conclusions: a) The winning teams made more ball possessions versus different types of defensive systems (mixed, zone pressure, man-to-man pressure) than losing teams; while the last ones generally made their ball possessions versus man-to-man and zone in half court ; b) The winners got more points scored per ball possession versus different defensive systems, while the losers usually made their ball possessions without scoring versus half court defensive systems (zone and man—to-man); c) The winning teams made more number of passes and spent more time duration their possessions of the ball versus different defensive systems than losing teams. This profile helps the coach to prepare practices and tasks to this specificity of defensive systems, and allow him to be ready to control these variables during the game in special situations like play-off series.