Agreement Between Methods to Determine Procedure for Maximal Exhalation During Hydrostatic Weighing: A Methodological Investigation

Abstract

Introduction: Current evidence suggests that there are many contentious issues that can significantly impact upon hydrostatic weighing assessments, for instance, obtaining reliable and precise data values within the testing environment. Whilst some researchers have addressed some of these issues, but there is still much uncertainty and significant challenges in terms of the procedure for maximal exhalation during hydrostatic weighing. Therefore, due to some of these challenges, it was necessary to conduct a methodological investigation to reduce measurement error.
Methods: Twenty-two students (n=22) were recruited from the University of Gloucestershire (BSc Hons) undergraduate programmes. All participants were over 18 years of age and all were free from disease, illness or injury (ᵡ±s; age=20.5±1.7 years, body mass=68.7±1.5 kg and stretched stature=172.0±8.3 cm).
Results: When comparing body mass in water values between the two exhalation techniques, (pre-submersion and post-submersion exhalation) results indicated systematic bias (lower value for post-submersion technique). There was a significant difference in body mass values between pre-submersion technique (Mean±SD=2.6±1.2 kg) and post-submersion technique (2.2±1.1 kg), t21=4.19, p<0.01.
Conclusion: When using hydrostatic weighing, the post-submersion exhalation technique was associated with greater measurement benefits thus resulting in a more reliable method.