The purpose of this paper is to analyze the offensive team activity and to determine factors influencing the teamwork intensity in basketball. We were able to determine the teamwork structure by using a system of analysis of the offensive process. The analysis of the team activity as
an integrated whole becomes very important. For this research we observed the Tallinn University basketball team, which plays in Division One of the Estonian league. The data was gathered from 600 ball possessions in 8 recorded games of the regular season. The data we collected (the count
of elements in the offensive zone during one team s ball possession: dribbles, passes, screens on the ball, screen off s the ball, shots; the time in possession during the transition, ball possession in the offensive zone and total time; the type of offence: fast break, early offence or set
offence; the beginning: after steal, defensive rebound or inbound) was analyzed by the means of data mining. Data mining summarises the data and presents the main patterns. It meets this target by listing the relations between all the values in each field and the dependent variable. The method
employs a unique algorithm that segments numeric fields in an optimal way, and displays the relation between each interval and the value under analysis. This analysis of the basic rules and trends results in the summary of the data. The analyzing system of the competitive activity of the
game, enables us to find out interesting offensive teamwork models from the data. The results showed that the teamwork intensity index was equal to 0,82 on average (SD = 0.26) with a frequancy of 43%. Trend report show, that the main impact factors influencing the teamwork intensity in offensive
zone are time in possession in offensive zone (prediction power 67), the total time of ball possession (prediction power 59) and screen off s the ball (prediction power 39). On the basis of the research, the coach can evaluate the activity of the team and correct the strategy for future
games. The analyzing system worked out through that helps coaches to develop performance and promote learning.