REPRODUCIBILITY OF THE HERITAGE FAMILY STUDY INTERVENTION PROTOCOL - DRIFT OVER TIME

PURPOSE: The primary goal of the HERITAGE Family Study was to document the role of the genotype in the response to aerobic exercise training . Toward this end, nuclear families were enrolled in a 20-week exercis e training program, with a large variety of tests performed before and after the training. Since study drift has the potential to adversely affect the results, reproducibility and potential bias over six consec utive 4-month periods were examined for selected test. METHODS: Intrac lass correlations (ICC), technical errors (TE), coefficients of variat ion within subject (CV), and means were calculated with use of the pre training test results for each of the six time periods. To check for h omogeneity, hypothesis tests were performed on the intraclass correlat ions and means. If homogeneity was not found across all six periods, f urther tests were performed to assess differences between pairs of tim e periods. RESULTS: There was little evidence for real drifts in repro ducibility, with most tests having ICCs of 0.8 or better. Only a few t ests showed any change over time, and in no case was there evidence of a systematic drift in mean values.CONCLUSIONS: Overall, the reproduci bility of the HERITAGE Family Study tests and assays considered in thi s paper was found to be very good, with no evidence of any systematic drift over time. (C) 1997 Elsevier Science Inc.