Errors in measurement of +G(z) acceleration tolerance

D. A. Ludwig, L. P. Krock

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Most accleration studies estimate a subject's G-level tolerance by taking only one determination (test) for a given condition. The purpose of this study was to examine the error structure and reliability of an individual's acceleration tolerance and to provide design considerations for future experimentation. A hierarchical (nested) design was used to estimate the sources of variation in measuring G-level tolerance. Six males rode relaxed in the USAF School of Aerospace Medicine human-use centrifuge and were exposed to a 0.1 G/s onset rate profile until greyout. Each subject was tested on three randomly selected days with three repeated determinations within a day. This design allowed for an estimate of both day-to-day and measurement error within a testing session. A single +Gz tolerance determination was found to be moderately unreliable (reliability coefficient = 0.74). Under the best of circumstances a subject's G-level tolerance cannot be estimated with any more accuracy than about ± 0.3 G with 95% confidence. This degree of accuracy can only be obtained with multiple measurements.

Original languageEnglish (US)
Pages (from-to)261-265
Number of pages5
JournalAviation Space and Environmental Medicine
Issue number3
StatePublished - Mar 21 1991

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health


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