ABSTRACT
Introduction Vital Capacity (VC) is measured by spirometry. VC can differ according to weight, age, gender, race and height of the investigated person. Repetition of the same tasks has been proven to enhance adults' performance. Encouraging on some tasks have shown to result in a significant difference. Aim This study aimed to examine if verbal encouragement and repetition of spirometry would make a difference in the results. Method This is a randomized clinical trial involving 136 healthy volunteers, randomly allocated to one of two groups: control and intervention groups. In both groups, VC was assessed as the baseline (VC1). VC was assessed again after ten days maximally (VC2). The third time of measuring VC was assessed again after ten days maximally (VC3). The verbal encouragement was provided only to the intervention group during iVC2 and iVC3, and only repeating was required from the control group in cVC2 and cVC3. Results and Conclusion There was no significant difference in VC after the third trial in the control group compared to the baseline measurement (p-value= 0.836). On the other hand, verbal encouragement in the third trial had a significant difference in VC compared to the baseline measurement (p-value= 0.000).
