title: Differences and relationships between residual volumes measured on land and in water calculated from estimate equations.
abstract: OBJECTIVE
  Residual volume error influences percent body fat estimated by hydrostatic. The aim of this study was to examine the differences and relationships between the residual volumes measured on land and in water and calculated from estimate equations developed in previous studies.
  
  
  METHODS
  
  
  
  METHODS
  20 males and 20 females, aged 18-25 years, participated in this study.
  
  
  METHODS
  the residual volumes on land and in water without submerging their head were measured twice in each setting. In addition, the residual volume was calculated from 6 estimate equations developed in previous studies.
  
  
  RESULTS
  Residual volumes measured on land and in water have very good trial-to-trial reliabilities (intraclass correlation coefficients: <0.98), and high relationships, and did not show a significant difference. It is inferred that their difference is approximately 500 mL, being larger than trial-to-trial error. If we attach great importance to practicability rather than the above error, the residual volume on land can be used. There were no significant differences between measured volumes and those estimated by equation 5 in males and all equations except equation 6 in females. The relationships between measured and estimated residual volumes were poor in males except for equation 4, but were fair in females. Trial-to-trial reliability of residual volumes measured on land and in water is very good, and they have insignificant differences and high relationships.
  
  
  CONCLUSIONS
  Of 6 estimate equations, equation 4 calculated from vital capacity has high accuracy in both sexes.
authors.affiliation: Faculty of Education, Kanazawa University, Kanazawa, Ishikawa, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Demura
authors.forename: S
authors.initials: S
authors.lastname: Yamaji
authors.forename: Y
authors.initials: Y
authors.lastname: Nagasawa
mesh_terms: D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D050218:Body Fat Distribution / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007101:Immersion; D008176:Lung Volume Measurements; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D012115:Residual Volume; D014797:Vital Capacity / Q000502:physiology*; D014867:Water
chemical_list: D014867:Water