Intervention
Subjects had five minutes of warm up and cool down before and
after each section. In this study, WST group was performed in two
sitting postures, which was a modified version of the intervention
studied and suggested by Verheyden et al. (2009). Two sitting postures
were performed on an exercise mat; one with the knees extended
and one with the knees flexed on the edge of the testing table. To
identify the training protocol for weight shifting, each subject’s range
of weight shifting was measured by a piece of graph paper placed
behind the participant’s back. Subjects were instructed to sit with
their arms folded and to shift their weights from midline to the right
and left, as far as they could. When the maximum range of weight
shifting was defined on each side of the movement on a stable surface,
a bar was placed 2 cm closer to the patient as a target marker for
WST program.
The WST group was performed in four conditions. For the first
condition weight shift, subjects were instructed to sit on an exercise
mat with legs extended, and have a balance pad under their buttocks.
The second weight-shift condition was to sit with legs extended, have
a balance pad under the buttocks, and a balance cushion under both
heels. For the third weight shift condition, subjects were to sit on the
edge of a testing table with a balance pad under the buttocks. The
fourth weight shift condition was to sit on the edge of a testing table,
have a balance pad under the buttocks, and a balance cushion under
the feet. Conditions 1 and 2 had a higher level of difficulty, because
the subject was to sit with the knees extended, which makes the buttocks
the center of gravity. These two conditions often made the subject
form a round back, and thus tactile and verbal cues to “straighten
your back” were continuously given while the therapist verified to see
that the back was straightened. The acromion was the landmark for
the weight-shift movement, where a marker was attached on the right
and left side. Subjects were instructed to shift their weight and touch
the bar placed on both sides by elongating the trunk on the weight
shifting side. Subjects were to hold the position for 10 seconds when
they reached the target point by shifting weight, and then return to the
starting position; this was counted as one trial. Each subject performed
three sets of 10 trials, rest for 30-second break between each
set, and a 1-minute break between each type of training