OBJECTIVE: To provide reference values and to evaluate the factors influencing thoracic mobility in children aged 7 to 11 years old. METHODS: A total of 166 children were assessed from public and private schools (90 girls and 76 boys) in the city of Natal (Northeast Brazil). Demographic and anthropometric data were collected, and the thoracic perimeter was assessed by cirtometry. Non-paired Student's t-test and variance analysis compared xiphoid respiratory coefficient between sex and ages, respectively. Axillary respiratory coefficient differences between sex and ages were tested by Mann-Whitney and Kruskal-Wallis tests, respectively, with differences located by Duncan post-hoc test. Spearman and Pearson correlation coefficients were used to verify the association between independent variables with the assessed coefficients. RESULTS: Xiphoid and axillary perimetry means were 5.00±1.59 and 4.75±1.56cm, respectively. There was a low correlation, without statistical significance, between xiphoid respiratory coefficient and age, sex, weight, height, and body mass index. The axillary respiratory coefficient was correlated with weight and height. Differences were found in the axillary respiratory coefficient in the age groups between 8-10 (p=0.03) and 10-11 years old (p=0.02). CONCLUSIONS: Reference values for thoracic cirtometry were provided for children aged between seven and 11 years old. Sex, age, weight, height, and body mass index did not influence xiphoid respiratory coefficient. The axillary respiratory coefficient was different between ages, from eight years onwards, being significantly influenced by height and weight regardless of sex.
respiratory muscles; evaluation methods; thorax; reference values
