They performed 70 practice trials after being randomly allocated to 1 of 5 experimental groups : training with ( 1 ) the paretic arm with direct view ( Paretic-No Mirror ) , ( 2 ) the nonparetic arm with direct view ( Nonparetic-No Mirror ) , ( 3 ) the nonparetic arm with mirror reflection ( Nonparetic Mirror ) , ( 4 ) both sides and with a nontransparent screen preventing visual control of paretic side ( Bilateral-Screen ) , and ( 5 ) both sides with mirror reflection of the nonparetic arm ( Bilateral-Mirror ) .