Ten male subjects ( mean SEM age : 29.4 1.5 years ; height : 178.8 1.5 cm ; body mass : 77.7 1.5 kg ) performed , in random order , 5 days of 6 head-down tilt ( HDT ) BR with no exercise ( CON ) , or BR with daily 25 minutes of quiet upright standing ( STA ) or upright locomotion replacement training ( LRT ) .