first try at high school basketball shots

New to shooting indoors in this type of enviroment and fast action, but am enjoying it and not knowing whats going to happen next ,the shots are of my nephew the young man in the black#22 uniform. The shots are from the stands so i know the composition is nothing special really just trying to learn my camera and lens setups and being able to find the sweet settings .
Both shots are with the sigma 24-70 at 70mm iso 800 1/200 fist apeture was 3.2 the second 2.8 I like this lens alot but find sometimes being so far away it tends to focus were you arent initially telling it (i set the focus to center continuous) i know if i got on the floor under the basket I could eliminate some of this! Any help or tips would be appreciated Thanks!

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That gym's lighting is great if you were able to use the Sigma at f3.2 and ISO 800.

You may want to give the 50/1.8 a try and shoot under the basket with higher shutter speed.

Other lenses such as the 88/1.8 and 100/f2 are mostly recommended for Bball.

Just get closer to the action.