The purpose of this study was to examine the effect of differences in number of players on performance in basketball games. Twenty male junior high school students participated in the present study. They played two types of games: Game A (court size : 24.6m×13.1m, 5 players per team, game time : 3 minutes), and Game B (court size: 24.6m×13.1m, 3 players per team, game time : 3 minutes). The distance covered and heart rate and RPE during the game were measured. Questionnaires were conducted after all of the games. The main results were as follows:
　　
1) The distance covered was significantly greater in game B than in game A. 　　
2) There was no significant difference in heart rate between the two games. 　　
3) RPE was significantly greater in game B than in game A. 　　
4) In the questionnaires about the two games, a significant difference was found only in one question “positioning" on the aspect of techniques. This value was significantly greater in game B than in game A.　　

These results suggest that amount of activity during the game and value of “positioning" in the questionnaires are increased with reduction in number of players.