I would stay away from Tanita (lower body analyzer) which we have found to be less accurate and reliable than other BIAs. Tanita has some new devices that assess both upper and lower body, and I have not studied those. If you are looking for an inexpensive analyzer, I would suggest Omron (upper body). The InBody (much more expensive) is also a good option. Our group have done multiple studies comparing these to gold-standard measurements. As you know, all of the BIA have pre-test recommendations that increase the reliability and validity of the measurements.
I have to dig for some papers, but here is an abstract from ACSM 2002
COMPARISON OF TANITA AND OMRON BIOIMPEDANCE ESTIMATES OF RELATIVE BODY FATNESS FOR PHYSICALLY ACTIVE WOMEN
A.L. Gibson1, V.H. Heyward2, J.M. Janot3, J. Chaves2, J. Schiller2, M.V. Wilmerding2, C.M. Mermier2
1Barry University, Miami Shores, FL; 2University of New Mexico, Albuquerque, NM; 3South Dakota State University, Brookings, SD; email: [email protected]
Purpose: This study evaluated the predictive accuracy of the Omron and Tanita bioelectrical impedance analyzers (BIA) in estimating the relative body fatness (%BF) for a racially-diverse sample of physically active women (N = 99).
Methodology: Inclusion criteria for this study were based on age (18 – 59 y); race (Black, Hispanic, or white); predominant training style (n = 49 aerobic, n = 50 anaerobic); regular physical activity or exercise; and absence of pregnancy, surgically-placed hardware, and metabolic disorders affecting muscle or bone. Subjects followed standard pretest guidelines for body composition assessments and gave written informed consent. Two estimates of %BF were directly obtained from the Omron BodyLogic (Model 300F), as well as from the Tanita (Model 02701001) analyzer. Reference measures were obtained using hydrodensitometry at measured residual volume and Siri’s two-component model formula. Significance was set at a = .05.
Results: Compared to %BFSiri, the predictive accuracy of the Omron (r = .87, SEE = 3.7 %BF) was better than that of the Tanita (r = .76, SEE = 4.9 %BF). There was no significant difference between the average %BFSiri (24.8 ± 7.6 %BF) and average %BFOmron (25.3 ± 6.8 %BF); however, the average %BFTanita (30.7 ± 7.7 %BF) differed significantly (p < .05). The Omron accurately estimated the %BF within ± 3.5 %BF for 94% of the sample, compared to only 18% for the Tanita.
Conclusion: Compared to the Tanita, the Omron yielded relatively more accurate estimates of %BF for the physically active women in this study.