Secondary Logo

Journal Logo

Cordain Loren; Richau, Leland L.; Johnson, James E.
Journal of Strength and Conditioning Research: May 1995
Article: PDF Only
Free

ABSTRACTBecause of the known alteration in the density, potassium content, and electrical conductivity of the fat free body mass (FFM) with extreme muscular hypertrophy, potential inaccuracies in the estimate of FFM could occur. Consequently, body composition was measured in 16 body builders to assess the variability among four commonly utilized procedures: hydrostatic weighing (HW), bioelectrical impedance (BI), skinfold measurements (SK), and total body potassium (TBK). The FFM from BI (71.5 ± 2.6 kg) was significantly (p < 0.05) lower than that determined from either SK (77.2 ± 2.7 kg) or TBK (77.6 ± 3.1 kg) measurements. In contrast, there were no differences (p > 0.05) between the HW FFM (75.4 ± 2.6) and BI, between HW and SK, or between SK and TBK. HW, SK, and TBK provide similar estimates of FFM in body builders; however, unless population-specific equations are used with BI, it underestimates FFM.

Because of the known alteration in the density, potassium content, and electrical conductivity of the fat free body mass (FFM) with extreme muscular hypertrophy, potential inaccuracies in the estimate of FFM could occur. Consequently, body composition was measured in 16 body builders to assess the variability among four commonly utilized procedures: hydrostatic weighing (HW), bioelectrical impedance (BI), skinfold measurements (SK), and total body potassium (TBK). The FFM from BI (71.5 ± 2.6 kg) was significantly (p < 0.05) lower than that determined from either SK (77.2 ± 2.7 kg) or TBK (77.6 ± 3.1 kg) measurements. In contrast, there were no differences (p > 0.05) between the HW FFM (75.4 ± 2.6) and BI, between HW and SK, or between SK and TBK. HW, SK, and TBK provide similar estimates of FFM in body builders; however, unless population-specific equations are used with BI, it underestimates FFM.

© 1995 National Strength and Conditioning Association