The influence of continuous feedback on EMG activity of the Trapezius muscule in female subjects performing a stress-inducing work-related computer task.

Moderate amounts of stress * the kind of short term stress * can help people
perform tasks more efficiently and to stay focused and alert. But when it is
getting too tough and life's demands exceed the individual*s ability to cope,
stress becomes a threat to both physical and emotional well-being. Long lasting
periods stress, the kind of unfavourable stress, are likely to occur in
occupational settings.
In Europe, occupational stress affects 28% of the working population, resulting
in a variety of aversive health effects. Costs, associated with aversive
effects of occupational stress are estimated to be at least ¤20 billion a year
in the EU in lost time and health bills.

One of the effective ways to reduce stress is to provide the subject feedback
on his physiological manifestations of the stress response, in practice known
as biofeedback. By providing feedback on physiological effects that one is
normally unaware of, individuals can learn how to alter their physiology in a
stress modifying way. One of the physiological manifestations of the stress
response is increased muscle tension. Therefore, a practice in which the
electrical activity of the muscles is measured and feedbacked to the subject is
frequently applied in stress management. This technique is known as
myofeedback.
Most myofeedback training sessions are provided on weekly basis with a maximum
duration of 20-60 minutes. It is however suggested that a more intensive
training approach, i.e. continuous training can further improve outcome as an
increase in practice and experience are associated with acquiring better
(motor) skills (i.e. muscle relaxation). Therefore, a training consisting of
continuous feedback that can be applied during working activities in the future
might be of additional value in the prevention and/or reduction of stress
related problems.
However, because no research has been performed yet exploring whether and to
what extend continuous feedback influences the physiological manifestations of
the stress response, the aim of this study is to investigate the influences of
continuous feedback on muscle activity during a stress-inducing work-related
activity.

The primary objective of this study is to explore the influences of continuous
feedback on electromyographic activity of the trapezius muscle in female
subjects performing a stress-inducing work-related computer task.
The secondary objective is to investigate the generalizability of the influence
of continuous feedback on muscle tension to other physiological manifestations
of stress, i.e. heart rate.

Longitudinal study (exploratory study)

To obtain the influence of biofeedback on electromyographic activity of the
trapezius muscle, feedback about activity of the neck-shoulder muscle is given
to the person by using the *orb*. The *orb* is a ball which changes from
colour depending on the amount of muscle tension (i.e. visual reflection on
muscle tension)

Based on literature, it can be concluded that the used work-related computer
task in this study will not harm the participant in a physical, an economic or
a psychological way. It can therefore be concluded that this protocol involves
no more than minimal risk: the risks of harm to a participant are not greater
than those ordinarily encountered in daily life or during the performance of
routine physical or psychological examinations or tests.