training

(れんしゅう) Practice – usually used with sports or performance (theater, band, etc.). Includes both physical and mental training.
 
(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.
 
(けんしゅう) Special advanced study – like at a post-graduate seminar.