2.5.2. Electrogoniometry
A twin axis goniometer XM65 (Penny and Giles Biometrics) was
used for measurement of the wrist postures in two anatomical
axes: flexion/extension and ulnar/radial deviation. Several studies
have reported using Penny and Giles Biometrics goniometers with
gloves (Moore et al., 1991; Larivière et al., 2004; Lu et al., 2008). The
attachment of the goniometers in this study was based on these
studies and the recommendations of Buchholz and Wellman (1997)
and Jonsson and Johnson (2001). One endblock of the goniometer
was attached on the dorsal skin of the hand over the third metacarpal
bone and the other endblock was attached over the forearm
dorsal skin so that the two endblocks were in alignment. Doublesided
tape was used for attachment of the endblocks on the skin
surface. Single-sided medical tape was also attached over the
endblocks for better connection and more security. The electrogoniometers
were then connected to a DL1001 data logger with one
of the channels used to measure flexion/extension and the other to
measure ulnar/radial deviation of the wrist. The sampling rate was
set at 200 Hz. Before each trial, the channels were calibrated so that
for both flexion/extension and ulnar/radial deviation, the zero
position was set when the hand and forearm were in alignment.
A second calibration position for flexion/extension was identified
when the hand was fully flexed and for ulnar/radial deviation when
the hand was fully deviated in the ulnar direction. Positive values
denoted extension and radial deviation, while negative values
denoted flexion and ulnar deviation. Wrist postures during the task
for both flexion/extension and ulnar/radial deviation angles were
characterised in terms of the mean position as well as the 10th and
90th percentile values, which described two extreme positions in
either direction (Bystrom et al., 2002).