The Effects of Maximum Voluntary Isometric Exercise by Using Visual Feedback on Muscle Activity of Upper Trapezius, Sternocleidomastoid and Craniovetebra Angle in Forward Head Posture

Foward head posture refers to a condition in which the head is tilted in front of the body's gravitational line in relation to the spine. It has been reported that the forward head posture usually results in a reduction of not only the neck extensor muscles, including the splenius capitis, and the upper trapezius, but also sternocleidomastoid. A total of 20 subjects with a craniovertebral angle (CVA) of less than 50 degrees were selected and experimented. The 10 members of the visual feedback correction group performed one set 10 times each 10 seconds to pull the chin while 10 members of the general correctional movement group performed one set 10 times every 10 seconds without looking at the screen. The experiment was conducted twice a week and for a total of four weeks. After 4 weeks of experimentation, four weeks after the end of the experiment, we compared muscle strength, muscle activity, and CVA. The results of the experiment showed a significant difference in the maximum muscle strength and %RVC, and the CVA of the visual feedback group, depending on the application and timing of the intervention (p<.05). There was a significant group difference in the maximum muscle strength of the upper trapezius,, the maximum muscle strength of the scapula, %RVC, and the angle of the head spine (p<.05). As a result, the maximum muscle force and the %RVC and the head scale angle of the target with the front head position did not work for four weeks after starting the calibration exercise, and when applied for about eight weeks, the calibration effect was obtained. It can be said that there were significant differences between groups (p<.05) when comparing continuous visual feedbacks and general calibration movements.