Definitely a monopod, unless you're shooting video.


You certainly don't need a tripod for stability while shooting high speed frame rates for sports. As stated above the monopod gives you much more mobility, as well as a smaller footprint near the sidelines, and it also enables you to get out of the way of a play more easily, as well as move around with the action of the game.


Also, a tripod definitely doesn't set-up as well in crowds or near; steps, seats, or the stands were people around you would tend to bump into it more easily.


Rich