In tennis you got to be mental tough, you got to think where to hit, how hard to hit, how to hit it (spin, flat, etc.) , and got to move quickly, forward, backwards, side to side. You also need to have great footwork rather than huge strides in track. In tennis, sometimes it's harder when playing outside with wind and the sun in your eyes. All you do in track is look forward with wind that effects nothing. You can play with others. In track, you have to compete for practice. But this only my opinion. Track = Tennis =