Background: Recently, there has been an emphasis on the use of interventions with biofeedback information for the maintenance or correction of posture.
Objects: This study assessed the change of trunk posture and trunk muscle activation when people exhibiting postural kyphosis performed visual display terminal work with or without a contact feedback device (CFD).
Methods: Eighteen right-handed individuals were recruited. Thoracic angle and right thoracic erector spinae (TES) muscle amplitude were analyzed. There were two sessions in these experiments. The control session involved 16 minutes of typing without a CFD, and the CFD session involved 16 minutes of typing with a CFD. The visual analog scale score was analyzed with a paired t-test, and the kinematic and electromyography data were analyzed through two-way repeated analysis of variance.
Results: The paired t-tests revealed that subjects had significantly less pain after the CFD sessions than after the control sessions (p<.05). Significant main effects by session and by time were observed in the thoracic kyphosis angle (p<.05). There was a significant session×time interaction for TES amplitude (p<.05), along with significant main effects by session and by time (p<.05).
Conclusion: The CFD caused people with postural kyphosis to straighten and to activate their TES continuously, even though they were habituated to bend their bodies forward. Therefore, the CFD was a beneficial treatment tool

Introduction
 Methods
  Subjects
  Experimental procedures
  Outcome measures
  Statistical analysis
 Results
  Visual analog scale (VAS)
  Fatigue effect
  Thoracic kyphosis angle
  Thoracic erector spinae electromyographyamplitude
 Discussion
 Conclusion
 References

• Joo-hee Park(Dept. of Physical Therapy, The Graduate School, Yonsei University)
• Sun-young Kang(Company-affiliated Research Institute, Korea Industry Development Institute)
• Heon-seock Cynn(Dept. of Physical Therapy, College of Health Science, Yonsei University, Dept. of Ergonomic Therapy, The Graduate School of Health and Environment, Yonsei University)
• Hye-seon Jeon(Dept. of Physical Therapy, College of Health Science, Yonsei University, Dept. of Ergonomic Therapy, The Graduate School of Health and Environment, Yonsei University) Corresponding Author