The results of this study indicate that ADP is both reliable and valid in female collegiate athletes and nonathletes when compared with DXA. In our populations of women, there were no significant differences in BF% or FFM between the two methods when DXA was used as the reference measure for ADP.
The current study suggests that ADP is a valid measure of BF% and FFM when referenced by DXA. This is the first study, to our knowledge that compared ADP with DXA in female collegiate athletes. Other work in female athletes that investigated the use of ADP for body composition analysis used hydrostatic weighing as a reference measure. One such report by Vescovi et al. (23) reported a significant overestimation in BF% in female collegiate athletes when ADP was compared with HW. In another study by Vescovi et al. (24) that included women ages 18–49, they reported that although the comparison between ADP and HW revealed no differences in those of “average” fat, ADP overestimated BF% in lean individuals. Research in other female populations have found upward trends in Bland-Altman analysis when comparing ADP with hydrostatic weighing (1,15), and ADP has been documented to overpredict BF% in lean and obese females as well as African-American men (9,25). Whether the results are influenced by sex or body fatness per se has yet to be completely elucidated. When comparing ADP with DXA, however, as in our population, the current data suggest that there are no significant differences in BF% between methods in female athletes and nonathletes. This is in contrast to reports of underestimation of BF% by ADP when compared with DXA in middle-aged men and women (20,26). Although, in one of the studies, the middle-aged men were overweight by definition, whereas the subjects in the present study were lean or normal weight (20). However, a study using a 4-C model that included DXA and isotope dilution documented that ADP under-predicted BF% in women of all levels of fatness (8).
The differences in results between our research and that of others may, in part, be due to certain methodological limitations. A limitation of the current study is that thoracic lung volumes were obtained using prediction equations instead of from measured volumes. However, McCrory et al. (18) suggests that predicted thoracic lung volumes are valid when performing ADP as compared with measured thoracic lung volumes. In addition, Bod Pod® has recently developed an S/T model that does not require lung volume measurements. We decided to use prediction equations rather than measuring thoracic lung volumes because most service facilities are unable to budget the money to support the necessary equipment nor the time to perform the lung volume measurements.
Of further consideration is the appropriateness of DXA verses hydrostatic weighing as a criterion measure in female athletes. Bone, mineral, protein, and hydration status are all biological factors, which may alter the correctness of this technique in female athletic populations under the constant assumptions. Therefore three-compartment methods such as DXA, which considers bone mineral density (BMD) presents challenge to two-compartment HW as a criterion measure by accounting for more individual variability in lean body tissue in effort to reduce error in body fat measurement (10). The use of DXA as a reference measure of body composition is supported by a report that indicated differences in BF% in DXA versus HW may be due to differences in bone mineral content (BMC) and lean body mass. This report by Kohrt et al. (14) suggests the potential for DXA as a superior reference measure for body composition compared with HW. Further support by Prior et al., who compared DXA with a 4-c model, suggests DXA is an accurate method of body composition assessment in a variety of ages, races, body types, and women of various ethnicities (11–13,19,27). In our study population of female athletes, this is a relevant consideration due to the wide variety of body geometry and composition of the females, as well as the nature of the sports represented within the athletic grouping. For instance, a sport such as track that loads the bone by nature of the activity would potentially present a distinct bone characteristics as compared with swimming, a weightless sport. In support, Duncan et al. (6) has documented that female track athletes had greater site-specific BMD than female swimmers.
These differences in bone characteristics present the need for a more complex model beyond the (2-C) that considers sport-related discrepancies such as bone. As previously stated, in our population of female college athletes, there were no significant differences in BF% when DXA was used as a comparison method for ADP. This is an important consideration in that DXA is becoming increasingly more popular as a criterion measure because of its inclusion of BMC and its relative comfort compared with HW.
1. Biaggi, R. R., M. W. Vollman, M. A. Nies, et al. Comparison of air-displacement
plethysmography with hydrostatic weighing and bioelectrical impedance analysis for the assessment of body composition
in healthy adults. Am. J. Clin. Nutr. 69: 898–903, 1999.
2. Bland, J. M., and D. G. Altman. Statistical method for assessing agreement between two methods of clinical measurement. Lancet 1: 307–310, 1986.
3. Collins, M. A., M. L. Millard-Stafford, P. B. Sparling, et al. Evaluation of the BOD POD for assessing body fat
in collegiate football players. Med. Sci. Sports Exerc. 31: 1350–1356, 1999.
4. Cureton, K. J., P. B. Sparling, B. W. Evans, S. M. Johnson, U. D. Kong, and J. W. Purvis. Effect of experimental alterations in excess weight on aerobic capacity and distance running performance. Med. Sci. Sports 10: 194–199, 1978.
5. Dempster, P., and S. Aitkens. A new air displacement method for the determination of human body composition
. Med. Sci. Sports Exerc. 27: 1692–1697, 1995.
6. Duncan, C. S., C. J. R. Blimkie, A. Kemp, et al. Mid-femur geometry and biomechanical properties in 15- to 18-yr-old female athletes. Med. Sci. Sports Exerc. 34: 673–681, 2002.
7. Fields, D. A., M. I. Goran, and M. A. McCrory. Body-composition assessment via air-displacement
plethysmography in adults and children: a review. Am. J. Clin. Nutr. 75: 453–467, 2002.
8. Fields, D. A., G. D. Wilson, L. B. Gladden, G. R. Hunter, D. D. Pascoe, and M. I. Goran. Comparison of the BOD POD with the four-compartment model in adult females. Med. Sci. Sports Exerc. 33: 1605–1610, 2001.
9. Fields, D. A., G. R. Hunter, and M. I. Goran. Validation of the BOD POD with hydrostatic weighing: influence of body clothing. Int. J. Obesity 24: 200–205, 2000.
10. Fornetti, W. C., J. M. Pivarnik, J. M. Foley, and J. J. Fiechtner. Reliability and validity of body composition
measures in female athletes. J. Appl. Physiol. 87: 1114–1122, 1999.
11. He, M., E. T. Li, and A. W. Kung. Dual-energy X-ray absorptiometry for body composition
estimation in Chinese women. Eur. J. Clin. Nutr. 53: 933–937, 1999.
12. Heyward, V. ASEP methods recommendation: body composition
assessment. JEPonline 4: 1–12, 2001.
13. Hicks, V. L., V. H. Heyward, R. N. Baumgartner, A. J. Flores, L. M. Stolarczyk, and E. A. Wotruba. Body composition
of Native-American women estimated by dual-energy X-ray absorptiometry and hydrodensitometry. Basic Life Sci. 60: 89–92, 1993.
14. Kohrt, W. M. Preliminary evidence that DEXA provides an accurate assessment of body composition
. J. Appl. Physiol. 84: 372–377, 1998.
15. Levenhagen, D. K., M. J. Borel, D. C. Welch, et al. A comparison of air displacement plethysmography with three other technique to determine body fat
in healthy adults. J. Parenter. Enter. Nutr. 23: 293–299, 1999.
16. Lohman, T. G. Advances in Body Composition
Assessment: Current Issues in Exercise Science, Monograph No. 3. Champaign, IL: Human Kinetics, 1992, p. 44.
17. McCrory, M. A., T. D. Gomez, E. M. Bernauer, and P. A. Mole. Evaluation of a new air displacement plethysmograph for measuring human body composition
. Med. Sci. Sports Exerc. 27: 1686–1691, 1995.
18. McCrory, M. A., P. A. Mole, T. D. Gomez, K. G. Dewey, and E. M. Bernauer. Body composition
plethysmography by using predicted and measured thoracic gas volumes. J. Appl. Physiol. 84: 1475–1479, 1998.
19. Prior, B. M., K. J. Cureton, C. M. Modlesky, et al. In vivo validation of whole body composition
estimates from dual-energy X-ray absorptiometry. J. Appl. Physiol. 83: 623–630, 1997.
20. Sardinha, L. B., T. G. Lohman, P. J. Teixeira, D. P. Guedesand S. B. Going. Comparison of air displacement plethysmography with dual-energy X-ray absorptiometry and 3 field methods for estimating body composition
in middle-aged men. Am. J. Clin. Nutr. 68: 786–793, 1998.
21. Utter, A. C., F. L. Goss, P. D. Swam, G. S. Harris, R. J. Roberston, and G. A. Trone. Evaluation of air displacement for assessing body composition
of collegiate wrestlers. Med. Sci. Sports Exerc. 35: 500–505, 2003.
22. Vanderburgh, P. M., and T. Edmonds. The effect of experimental alterations in excess mass on pull-up performance in fit young men. J. Strength Cond. Res. 11: 230–233, 1997.
23. Vescovi, J. D., L. Hildebrandt, W. Miller, R. Hammer, and A. Spiller. Evaluation of the BOD POD for estimating percent fat in female college athletes. J. Strength Cond. Res. 16: 599–605, 2002.
24. Vescovi, J. D., S. L. Zimmerman, W. C. Miller, L. Hildebrandt, R. L. Hammer, and B. Fernhall. Evaluation of the BOD POD for estimating percentage body fat
in a heterogeneous group of adult humans. Eur. J. Appl. Physiol. 85: 326–332, 2001.
25. Wagner, D. R., V. H. Heyward, and A. L. Gibson. Validation of air displacement plethysmography for assessing body composition
. Med. Sci. Sports Exerc. 32: 1339–1344, 2000.
26. Weyers, A. M., S. A. Mazetti, D. M. Love, A. L. Gomez, W. J. Kraemer, and J. S. Volek. Comparison of methods for assessing body composition
changes during weight loss. Med. Sci. Sports Exerc. 34: 497–502, 2002.
27. Van Loan, M. D., and P. L. Mayclin. Body composition
assessment: dual-energy X-ray absorptiometry (DEXA) compared to reference methods. Eur. J. Clin. Nutr. 46: 125–130, 1992.