Reliability of the double product break point measurement

No Thumbnail Available
Authors
Hargens, Trent A.
Advisor
Kaminsky, Leonard A., 1955-
Issue Date
1999
Keyword
Degree
Thesis (M.S.)
Department
School of Physical Education
Other Identifiers
Abstract

The double product break point (DPBP) has been shown to occur in normal and cardiac subjects with values comparable to the ventilatory threshold (VT). The purpose of this study was to evaluate the intramodal and intermodal reliability of DPBP measurements during treadmill (TM) and cycle ergometry (C) exercise and to compare the DPBP to the VT. Seventeen subjects, (eight men and nine women) ages 18-60 (31.5 ± 12.4 yrs), performed four maximal exercise tests, two utilizing a standardized ramp treadmill and two utilizing an individualized ramp cycle protocol. A minimum of 48 hours separated each test. Double product (DP) was measured every 15 seconds during each test via the Kyokko Bussan CM-4001 automated blood pressure unit. Breath by breath analysis of gas exchange measurements were performed. The DPBP and VT was determined visually by three blinded observers (acceptance criteria being at least 2 observers agreeing within 10%). There were no significant intramodal differences in the V02 at the DPBP (ml'kg'1'min 1) for the two treadmill trials (23.8 + 4.9, 23.2 ±5.0) or for the two cycle trials (21.7 +7.2, 21.7 ±6.4). There was also no significant mean intermodal difference in the V02 at the DPBP for the treadmill and cycle (24.4 + 4.4, 23.1 + 5.8). Intramodal intraclass correlations for the DPBP were 0.84 and 0.79 for the treadmill and cycle, respectively. Intermodal intraclass correlation for the DPBP was 0.85. There were significant differences between the DPBP and the VT for both the treadmill (23.3 + 4.7, 28.2 ± 5.3)and the cycle (22.1 + 7.1, 27.5 ± 10.4). Correlations for the DPBP/VT comparison were 0.43 and 0.78 for the treadmill and cycle, respectively. In conclusion, results of this study suggest that DPBP measurements are reliable both intramodally and intermodally, however due to a wide range in correlations, the results suggest that the DPBP and VT are not occurring at similar V02 values.

Collections