training

練習(れんしゅう)	Practice – usually used with sports or performance (theater, band, etc.). Includes both physical and mental training.

訓練(くんれん)	Martial arts / basic training in the army. The connotation is that it’s physical, and you do it over and over until you become a master of it.

研修(けんしゅう)	Special advanced study – like at a post-graduate seminar.