Effects of at-work exercises on computer operators
From: Work 28 (2007) 67–75
At-work exercises are commonly recommended for computer operators. This randomized control trial assessed adherence, pain and satisfaction after 4 weeks of at-work exercise. Subjects (n = 72) were randomized into 3 groups: resistance exercise, stretching, and control. Outcomes included a satisfaction survey, a visual analogue pain scale, a pain drawing, and the Neck Disability Index. The Visual Analog Scale, the drawing, and Neck Disability Index were analyzed together as a composite variate referred to as Pain Impact. Exercise frequency was similar across the 3 groups (median = 1.5 times per day). No differences were found between groups on Pain Impact or individual pain variables. Most satisfaction survey item scores did not differ between groups. However, a significant difference between groups on the survey item related to discomfort. The resistance and stretching group differed from the control group with regard to their perception that the exercises were helpful in reducing discomfort in the back and neck. We conclude that most subjects found the resistance and the stretching exercises easy to do, performed them 1 to 2 times daily, and said they reduced discomfort. To determine optimal type and frequency of at-work exercises, further study is needed.
Concurrent with increasing use of video display terminals, an alarming incidence of musculoskeletal disorders associated with computer use has been reported. A study of neck/shoulder discomfort prevalence in video display terminals operators found that 61.5% experienced some discomfort and 7.5% experienced intense discomfort. Other authors have reported that 27% of video display terminals operators experience almost constant neck discomfort, and 30% experience frequent pain. Gerr et al. found that more than 50% of computer operators reported musculoskeletal symptoms over a 3 year period. In computer operators, the cervical region is reported to be the most commonsite of musculoskeletal pain.
The development of musculoskeletal pain or discomfort in computer operators is theorized to be multifactorial, and includes occupational, ergonomic, psychological, psychosocial, and demographic parameters. Occupational and ergonomic factors include workstation design, task diversity, work/task demands, rest cycles, and posture. Marcus et al. found that postural factors were associated with upper quarter musculoskeletal symptoms in computer operators. A review of epidemiological studies concluded that posture is an independent risk factor for development of work related musculoskeletal disorders among computer users. Constrained, prolonged, or static postures lead to undesirable EMG muscle activity and discomfort. Infrequent postural changes and presence of discomfort while sitting are predictive of musculoskeletal problems. Self-reported exposures to mouse and keyboard use have been shown to predict elbow, wrist and hand symptoms in computer operators. The number of hours spent performing keyboard operation appears to be a risk factor for work related musculoskeletal disorders.
It has become common practice to recommend exercises for individuals who work at computers. Exercises may serve to provide a break from static postures, promote postural correction, and encourage movement. In addition, exercises may be used to stretch or contract muscles. A review by Lee in 1991 found 123 different exercises that have been recommended for computer users. Recent peer reviewed publications have recommended a variety of exercises for video display terminals operators. Several mass market books, geared toward enhancing comfort and reducing pain for office workers, recommend a vast array of exercises.
It is widely accepted that resisted exercises can enhance muscle performance and force production. Resisted exercise may also be advocated for postural realignment, although evidence supporting its use for this purpose is lacking. Therapeutic exercises of various types, including resisted exercises, have been demonstrated to be efficacious for specific musculoskeletal disorders such as chronic neck or back pain.
Stretching exercises may be utilized to promote flexibility and extensibility of joints and muscle tendon units. Stretching is also felt to be an effective intervention for spinal pain syndromes of nociceptive origin. Stretching has also been advocated for prevention of injuries associated with work or athletic performance, although evidence regarding prevention effectiveness is mixed.
Based on the authors experience and review of literature, there appears to be a trend for recommendation of stretching exercises for computer operators. Ironically, despite its widespread promotion, evidence to support the efficacy of any mode of exercise for computer operators is limited, and in some instances, contradictory.
Clearly, more work is needed to elucidate the effects of at-work exercise on computer operators, as well as determine optimal modes of exercise and dosages. This randomized controlled trial sought to address the following questions with regard to video display terminals operators: (1) Does a 4-week program of at-work exercise have an effect on neck and upper back pain? (2) What is the adherence to at-work exercise programs? (3) What is the self-reported satisfaction of computer operators regarding at-work exercises?
Subjects were randomly assigned to 1 of 2 experimental groups or a control group. Experimental groups consisted of a resistance exercise group and a stretching exercise group. Resistance exercises included isometric cervical spine rotation with manual resistance (5 second hold, 5 repetitions in each direction), shoulder shrugs with elastic band resistance (12 repetitions), and scapular retraction with elastic band resistance (12 repetitions). Stretching exercises included a lateral cervical stretch (5 second hold, 5 repetitions in each direction), a posterior neck stretch (5 second hold, 5 repetitions), and an anterior arm/forearm stretch (5 second hold, 5 repetitions). Subjects assigned to the control group performed deep breathing (5 repetitions) and seated ankle pumps (10 repetitions). Subjects in the control group received similar amounts of instruction and attention. The control group’s activities were selected because they did not produce any visible cervical spine/upper back movement or postural changes. All subjects received verbal instruction, visual demonstration, and graphic illustrations of the exercises or control group activities. Subjects were instructed to perform their exercises or control activities twice a day while at work for a period of 4 weeks. Subjects received weekly reminder phone calls or emails (from one of the investigators) to remind them of the suggested frequency. Subjects were provided with a paper and pencil journal for daily record keeping over the course of the study.
The majority of subjects in the stretching exercise group and the resistance exercise group reported that the exercises were helpful in reducing discomfort in the neck and upper back. Subjects in the stretching group or the resistance group, when compared to control group, were more likely to report a perceived reduction of neck and upper back discomfort. Despite this finding, there was not a significant difference in pain outcomes between groups. This may be partly explained by low baseline scores on pain variables. It is interesting that even subjects with low baseline pain perceived a reduction in discomfort in the neck and upper back. It may be that some subjects experienced discomfort that was not pronounced enough for them to describe as pain. For the majority of subjects, there may be self-efficacy value in either stretching or resistance exercises for reduction of discomfort Future research should explore use additional quantitative tools to capture discomfort ratings, such as the scale used by Fenety and Walker. Further study is needed to elucidate if stretching is preferable to strengthening, or visa versa, but our data suggest that either type of exercise is helpful in reducing discomfort.
The stretching exercises used in this study may be easier to implement in an office setting, since they did not require the use of any equipment. However, subjects generally felt that any of the exercises were easy to do. Clinicians should consider that the strengthening exercises used in this study might be appropriate in the work setting. Our finding is consistent with Waling et al., who reported that any one of 3 different types of exercise programming had a beneficial effect when compared to control. One possible explanation for this is that either of the exercise programs used in this study provided the computer operator with postural variation, movement, and contraction and/or lengthening of muscles, thus negating the adverse effects of working in static postures for prolonged periods.
The results of this study were mixed. Although the perceived reduction in discomfort was significant, we did not find a significant difference between groups on Pain Impact. There were a number of theoretical and methodological limitations that may have prevented us from identifying the effects of at-work exercise on pain. First, the Visual Analog Scale scale included in our Pain Impact composite variable was “current pain”. It may be more advisable to consider “average pain” than pain at one instant in time. Furthermore, although the pain drawing, Neck Disability Index, and current pain Visual Analog Scale were correlated (and thus analyzed together as Pain Impact), we question the value of including the pain drawing as a marker of improvement. Waling et al. found no significant change in pain drawing despite improvement in other pain ratings when studying the effects of training on females with trapezius myalgia. One explanation for this could be that location of symptoms (and the surface area of the body involved) may not change, but is it still quite plausible that the intensity or character of pain can improve greatly. Therefore, clinical improvement in pain may occur in the absence of changes in pain drawing scores.
The authors also observed that our subjects had relatively low baseline scores for current pain Visual Analog Pain Scale (mean = 1.16 cm on a 10 cm Visual Analog Scale) and Neck Disability Index (5.06 on a 50 point scale). This created a ceiling effect, i.e., because our subjects tended to have negligible or mild amounts of current pain or disability at baseline, they did not have the potential for significant improvement on these variables. For example, the minimal detectable change score for the Neck Disability Index is 5 points. At baseline, the mean Neck Disability Index score was 5.1 points. Clearly, if subjects in the study had higher baseline scores in our pain and disability variables, there would have been greater potential for them to realize meaningful improvement. Future research of the effects of at-work exercises on pain should include subjects with at least moderate amounts of pain and disability at baseline, and use a more elegantly designed model to capture pain data.
Our control group subjects may have experienced a benefit from the deep breathing exercises as well as the attention that they received. Deep breathing can have an effect on EMG activity of the trapezius, a major extensor of the cervical spine. In addition, pausing to take deep breaths may have helped attenuate stress and provided a brief rest from work related activity. This may explain why some subjects reported a perceived reduction in discomfort even with the control activities. Thus, our control group did not receive a true placebo intervention, and future research in this area should reconsider the use of deep breathing exercises in control group.
Several methodological limitations described in the discussion prevent the authors from making any strong conclusions regarding the effect of at-work exercises on pain in computer operators. However, either the stretching or strengthening exercise programs were effective in reducing perceived discomfort, when compared to a control group. Otherwise, satisfaction was not different between groups. With thorough instruction and weekly reminders, adherence to the exercise programs was generally good over a period of 4 weeks.
We recommend specific neck exercises that are simple to do and target more specifically structures related to postural neck pain and feel they should be the first line of defense in work related postural neck pain as consistent with current literature.
The post-intervention questions:
1. The exercises were helpful in reducing discomfort in my neck and back.
2. The exercise program was helpful in reducing stress.
3. Performing the exercises at workwas easy to do.
4. I will continue to do the exercises now that the study is over.
5. Overall, I have a favorable opinion of the exercises.
