Brozek two-compartment model under-estimates body fat in black female athletes

Examining Race-Related Error in Two-Compartment Models of Body Composition Assessment: A Systematic Review and Meta-Analysis

BACKGROUND

The Brozek and Siri formulas estimate relative adiposity (%Fat) from total body density (D_b) using a 2-compartment (2C) model. Racial/ethnic differences in D_b have been reported, along with subsequent errors in estimated %Fat.

OBJECTIVE

The primary aim of this systematic review and meta-analysis was to examine potential race/ethnic differences in the accuracy of the Brozek and Siri 2C formulas using aggregate-level data.

METHODS

Peer-reviewed studies available in English that provided 2C and 4C estimates of %Fat were located using searches of the PubMed (n = 150), Scopus (n = 170), and Web of Science (n = 138) online electronic databases. Random-effects models were used to determine potential differences between racial groups using a mean ES and 95% confidence intervals.

RESULTS

The cumulative results from 78 effects indicate that the relative accuracy of the Brozek equation did not vary between racial groups (between group p = 0.053). In contrast, the Siri equation slightly underestimated %Fat for Asian adults (ES_WMD = -1.40%, 95%CI -2.33% to -0.46%; p = 0.004) and Black adults (ES_WMD = -1.10%, 95%CI -2.11% to -0.08%; p = 0.034), with no significant differences observed in Hispanic adults (ES_WMD = 0.64%, 95%CI -1.02% to 2.31%; p = 0.448) and White adults (ES_WMD = 0.08%, 95%CI -0.42% to 0.57%; p = 0.766) (between group p = 0.019).

CONCLUSION

Small, but statistically significant, error was found between racial groups when estimating %Fat using the 2C Siri equation when compared to 4C models. However, the observed error due to race/ethnicity appears to be of little clinical or practical significance when using either equation.

Validity of the current NCAA minimum weight protocol: a brief review

Historically, collegiate wrestlers have been associated with utilizing rapid weight loss methods to reach a desired weight class. Following three deaths in 1997, the National Collegiate Athletic Association (NCAA) implemented a program which prevents wrestlers from wrestling below a minimum weight (MW) of 5% body fat. Although numerous studies have investigated adolescent wrestlers, few have investigated collegiate wrestlers using the methods outlined by the NCAA. The purpose of this review paper is to outline potential problems with the current NCAA protocol as well as critique studies investigating the validity of methods to assess MW.