Speedbird744
For any training in the US you must go through the TSA on line application. In answer to your question NO you do not need a visa AS long as you have a return ticket booked with your arrival date and departure date as indicated on your on line TSA.
Your training provider has the latest updated information and so as long as your training is less than 90 days your ok. So yes it is fine and dandy.
Have fun
Mr W