Effects of backpack load on balance and decisional processes.

A dual-task method was employed to assess the effects of backpack carriage weight on 20 young adults' balance and rapid decision making. During two separate sessions, participants' balance was perturbed during 18, 60-second trials by altering visual and/or somatosensory conditions. Concurrent balance control and auditory choice-reaction task performance were assessed. Each participant wore an all-purpose, lightweight, individual, carrying equipment (ALICE) backpack containing a load equal to 30% of his/her body weight throughout one session. Within-subjects analyses revealed that carriage load disrupted balance control and degraded cognitive processes but only on trials that required executive, higher-level, mental processing. The magnitude of the effects of the backpack load on balance and cognitive performance was similar over 22 minutes of testing. Carriage load degrades both balance control and situational awareness of ROTC cadets.