Saskia Baltrusch

52 Chapter 3 2.3 Testing Procedure Each measurement session began with fitting and adjusting the exoskeleton to the participant. Height, weight, trunk height and chest circumference of the participants were measured and a first questionnaire related to their work ability was completed. Before the start of the test battery every participant could walk a few steps, do some squats and move a bit in the exoskeleton to get habituated to it. Participants then performed a series of functional tasks in two conditions 1) with the exoskeleton (Exoskeleton condition) and 2) without the exoskeleton (Control condition). The starting condition and the sequence of the tasks were randomized to prevent order and habituation effects. Functional performance was assessed with objective outcomes and with subjective outcomes: perceived task difficulty and comfort of the device, by using questionnaires after each of the tasks. An overall impression questionnaire regarding the exoskeleton was completed by the participants at the end of the session. All measurements were done on the same day. 2.4 Selected tasks The selected tests and related objective and subjective outcome measures are summarized in table 1. The tasks were selected to provide a test battery of realistic working tasks and to test the exoskeleton’s versatility. The first selection of tasks was based on the list of tasks that are considered in the functional capacity evaluation (FCE, Isernhagen Work Systems), an assessment method that realistically and reliably judges work-related physical performance capacity [15]. Other tasks were added based on workplace observations. We did not prescribe a given technique for task execution to keep the assessment of functional performance as close as possible to real-life situations.