Validation of Predictive Dynamics Tasks - Human Motion Simulation: Predictive Dynamics - page 209

FIGURE 9.2
Santos s marker placement protocol.
the acromion and the axilla, over the medial and lateral epicondyles of the
humerus, over the radial and ulnar styloid processes, and over the 2nd and 5th
metacarpal heads.
Collected marker motion data are smoothed using a Butterworth filter; the cut-
off frequency is usually 8 Hz, but it would depend on the frequency content of
the motion for high-speed motion. The subjects are instructed to stand in a neutral
position, referred to as the T-pose, which corresponds to the initial joint angles
and segment locations of the skeleton. The T-pose is defined as standing with feet
shoulder width apart and parallel, and arms raised parallel to the floor in the
transverse plane and lateral to the body in the frontal plane. Palms face forward
with the elbows maximally extended and the olecranon process pointed towards
the ground.
9.3.4 Subject preparation and data collection
When a subject comes into the motion capture lab, they put on the motion capture
suit, and markers are placed on their body according to the previously defined
marker placement protocol. Bony landmarks are carefully located, and corre-
sponding markers are placed accordingly to reflect these anatomical reference
points ( Karduna et al., 2001 ; Oyama et al., 2001 ). Figure 9.3 shows the marker
placement schemes.
Subjects are first instructed to stand in the T-pose. The first trial in each
motion capture was a range of motion (ROM) trial. In the ROM trial, the
subject performed a series of movements that isolated each joint. Some of these
movements were head flexion/extension, arm circles, hip rotations, bending