• Sukalya Kritsnakriengkrai Division of Physical Therapy, Faculty of Physical Therapy, Srinakharinwirot University.
  • Nadanun Changniem Division of Physical Therapy, Faculty of Physical Therapy, Srinakharinwirot University.
  • Niphon Teeranon Division of Physical Therapy, Faculty of Physical Therapy, Srinakharinwirot University.
  • Aditep Kwansu Division of Physical Therapy, Faculty of Physical Therapy, Srinakharinwirot University.


Respiratory Muscle, Inspiratory Pressure, Expiratory Pressure, Reference Value


The maximal inspiratory pressures (MIP) and maximum expiratory pressure (MEP) are commonly used for evaluating inspiratory and expiratory muscle strength. To date, there have been no normal values representing of MIP and MEP for Thai people. The aims of this study were to determine the normal values of MIP and MEP in Thai people and the correlation of MIP and MEP with anthropometric data. The sample size was calculated using the Yamane formula and recruited from the population by convenient sampling. Four hundred and five healthy volunteers (167 males and 238 females) aged between 20 and 60 years old were included. Blood pressure, height, weight, percent body fat, pulmonary function, and inspiratory and expiratory muscle strength were measured. The results of this study found that the means of MIP and MEP in males were 105.4 cmH2O and 134.2 cmH2O and in females were 74.3 cmH2O and 90.8 cmH2O, respectively. The MIP and MEP in males were significantly higher than in females in every age range (p<0.001). There was a positive correlation of MIP with height (r = 0.381, p<0.001), weight (r = 0.155, p<0.001), body mass index (r = 0.257, p<0.001), and negative correlation of MIP with percent body fat (r = - 0.229, p<0.001). MEP had a positive correlation with height (r = 0.360, p<0.001), weight (r = 0.147, p<0.001), and body mass index (r = 0.194, p<0.001) and had a negative correlation with percent body fat (r = - 0.262, p<0.001). There was no correlation between MIP or MEP and age. In conclusion, the normal values of respiratory muscle strength in Thai people both males and females were determined. Respiratory muscle strength had a positive correlation with height, weight, and body mass index, and had a negative correlation with percent body fat but had no correlation with age.


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How to Cite

Kritsnakriengkrai, S., Changniem, N., Teeranon, N., & Kwansu, A. (2024). RESPIRATORY MUSCLE STRENGTH VALUES IN THAI PEOPLE. Srinakharinwirot University Journal of Sciences and Technology, 16(31, January-June), 1–13, Article 253648. Retrieved from