EFFECT OF STRETCHING EXERCISES ON TRAPEZIUS WORKLOAD USING MVIC AS AN INDICATOR

The substantial increase in using the desktop in offices is directly associated with Work Related Upper Limb Disorders (WRULDs) where an average workload on trapezius of 4hours/- day in females, is the main cause. Ergonomically inappropriate work station may increase the static muscle load at bilateral shoulder and wrist joint where keyboard is mostly responsible. Intermittent rest periods and varying positions are found significant during constant sedentary work. The aim of this study was to determine the effect of active stretching on the upper fibers of trapezius using desktop computer measured by MVIC. A 22 years old left hand dominated female typing with an average frequency of 4 hours/day with 40 words/minute. An adjustable VDU was placed with arm, wrist and foot support. A word processing task was allotted for 20 minutes before and 20min after the stretching. The Root Mean Square (RMS) for the EMG were collected at the intervals of 6th, 9th, 12th, 15th, and 18th minutes during typing. Subject performed three stretches of 20sec at the end followed by a rest period. The results reveal that resting EMG of the dominant hand was found to be 21% of MVIC where amplitude of EMG of the dominant hand is higher than the non-dominant (more than 10% higher). Stretching exercises decreased the activity of trapezius by 1.1% and the residual effect lasted for less than 12minutes. It is suggested that 20 seconds of static stretching between the intervals were found to be effective in reducing the workload for the students. Studies on larger scales should be conducted for especially research and postgraduate students and proper workstations should be recommended for them.