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A couple of thoughts.
1. Perhaps your lens doesn't focus fast so it doesn't keep up the the fast moving action in AI Servo
2. I haven't done these type of pictures, however if it was me I would try using the centre point and just keep it on the subject (your daughter) with the back button focus pressed, and do a burst of shots when the action is right.. Have a little less zoom and crop as required in post.
If it were myself, as everyone and yourself have already figured, use single point focus.
Now I see you are using apertures down to f7.1 in second one, BUT also see that the girl 20ft or so back is still in focus. Use an aperture down around 4.0-5.6 and up the shutter a bit to 1250-1500 to get the action just that much sharper with the freeze-frame capability, along with separating the action from the background more.