Saskia Baltrusch

92 Chapter 4 The protocol was split into two parts: (1) Walking and (2) Repetitive Lifting (Figure 2). First the walking tasks were performed, followed by the lifting experiment. Both protocols were performed on the same day. Figure 2: Oxygen consumption, muscle activity and kinematics were measured during repetitive lifting (left) and walking (right). In the walking protocol, a motorized treadmill (Forcelink, Culemborg, The Netherlands, dimensions: 3X5m) was used. To find preferred walking speed with and without the exoskeleton, a single marker was attached to the trunk of the participant. Subsequently, the participant walked on the treadmill in the ‘self-paced mode’, in which the treadmill adapts its speed to the speed of the participant based on tracking of the participant’s position on the treadmill [25]. As soon as the treadmill reached a steady state, the walking speed was noted. After that, the oxygen consumption mask was fitted to the participant and single markers were attached to the shoes. The participant then performed two 5-minute trials: normal walking without the exoskeleton (Control Condition)