Jim makes a good point about panning, and I pan regularly.You have to, in order to follow the action on the court. I did a major tournament two weeks ago and set the strobes up, pointing into a ceiling corner. Fired the strobes at 100%, shot ASA200, 1/250 and f3.5 to 4.2. I took some of the best shots I have taken this year. Again, probably 1/3 of the images were blurred to some extent, so I went back and looked at them.
What I think is happening is that it's an auto focus issue. In all the poor images, there was always a section, or player that was in focus - but not always on the "key player". The auto focus sensor that I select is in the center of the matrix, and apparently it sometimes will pick up a on a spot that is not where I want to capture action - like a player behind the "action".
The strobes are a bit of a pain to set up, but I have it down to about 20 minutes from the time I open the bag to when I am ready to shoot. I'd be hard pressed to go back to available light, 800ASA f 1.4 - f1.8 shooting unless forced to do so. The enhanced light and stop action is much superior and provides me with more usable images. On Camera flash is an option, but delivers very harsh shadows and offers limited floor coverage.
When we publish to our website for sales we usually load about 1/4 to 1/3 of the take - so out of 100 to 150 shots 35-50 might end up on line. Some are not crisp, some don't have enough interest or action, and some are just not good enough to load. When I first started shooting basketball 4 years ago, I'd shoot 300 plus shots in one game - and If I got 10 decent ones, I was happy, so I guess time, experience, lighting and technique all help.