I believe the long toss is a good SUPPLEMENT to your velocity training that is already in place. The reason for that being is that long toss will not necessarily increase your velocity. That should not be your goal when you long toss. Studies done by Tom House and Coop DeRenne have shown that pitcher’s that rely strictly on long toss to improve their velocity actually lose a little bit of it. Your goal should be to stretch out your shoulder when you are throwing from long distances. It is an exercise that is designed to stretch and create endurance.
I also believe that there should be no limits to how far you long toss, HOWEVER you need to build up to that distance instead of just going out to 300 ft on your first session. You must be sure to maintain the same throwing mechanics that you use when throwing from 75 ft. A good program to look at when discussing long toss is Alan Jaeger’s long toss program. He has worked with many successful pitchers that swear by his programs. Just google his name, go to his website, check out the articles on there, possibly buy his DVD and go from there. I have puchased his DVD and I learned a lot from it. I had several questions when I got done watching it so I e-mailed them and recieved a response from them answering my questions that same day. Check it out. It never hurts to get a well-rounded view on a sometimes controversial topic.