I already recommended the 85mm lens for volleyball and basketball based on both the results I get using and 85mm lens for indoor sports and after looking at a couple of series where I used the 70-200mm lens. Using the 70-200 most of the shots I liked best were in the neighborhood of an 85mm lens.
I just finished taking a look at some shots I took last spring at a track meet. Some, but not all were in the neighborhood of an 85mm lens.
For Shot Put, Discus, Javelin and high jump the 85mm will work. You will need to frame with your feet and you can't shoot from the bleachers. You will need to talk with the athletic director about getting access to the field. Perhaps offer to share photos with the school and shoot more than just your own children.
For track events my focal length was all over the place but about 1/3 were in the neighborhood of the 85mm lens.
For long jump, again all over the place, but from the moment they jump to their landing I was in the neighborhood of the 85mm when shooting from the barrier at the end of the sand pit.
Also, just curious, how did your shoot at the last basketball game go? I would love to see a couple of frames posted here.