Questionnaire results () showed that, generally, the workstation exercises were considered satisfactory and easy to perform, made the directory assistance operators feel better at day's end, and did not make them feel conspicuous (ie, exposed to unwelcome view). Although 3 subjects reported some minor discomfort, the operators' main concern was difficulty remembering or finding time to perform the exercises, particularly when “calls waiting” was posted on their computer screen.
The independent variables evaluated were workstation exercises (preexercise, exercise) and time (start, hour 1, hour 2) within each test. The effects of exercise and time on ICM were measured with an exercise (2) × time (3) repeated-measures analysis of variance (ANOVA). For analysis of perceived discomfort data, a between-subjects factor (time of day: morning start/afternoon start) was added to the 2 within-subjects factors (exercise and time). For both analyses (ICM, perceived discomfort), in the presence of nonzero two-way interactions, the analysis of simple main effects was used to evaluate the effects of each independent variable at each level of the other independent variable (eg, the effect of exercises at hours 1 and 2). All analyses were conducted using SPSS, with alpha set at .05.
We believe that our study is unique because we demonstrated increases in ICM after introduction of workstation exercises. Results also showed that, when using workstation exercises, operators rated their musculoskeletal discomfort lower compared with the pre-exercise conditions.
The test protocol for both ICM and perceived discomfort data collection is illustrated in . Subjects provided perceived discomfort ratings at the 30-, 65-, and 115-minute marks. For each perceived discomfort rating, subjects were asked to close their eyes and evaluate discomfort by briefly focusing on each body part being characterized in turn. In order to evaluate ICM trends that coincided with ratings of perceived discomfort, ICM data were analyzed as the mean of 3 blocks at the start of the test (minutes 5–20), at the end of hour 1 (minutes 50–65), and the end of hour 2 (minutes 100–115). Subjects signed off their computers to rate their perceived discomfort. During the exercise test, subjects were not told to take an exercise break. Henning et al suggested that encouragement to do workstation exercises is not enough to get subjects to do exercises. Therefore, subjects were cued visually (at 35, 65, and 90 minute) when 30 minutes had passed. These 30-minute cues were outside the time period when ICM data would be analyzed ().