Submitted on October 15, 2006
Accepted on July 9, 2007
Modeling upper and lower limb muscle volume by bioelectrical impedance analysis
Alexander Stahn1*, Elmarie Terblanche2, and Gunther Strobel3
1 Department of Sport Science, University of Stellenbosch, Stellenbosch, Western Province, South Africa; Institute of Sports Medicine, Free University of Berlin, Berlin, Germany
2 Sport Science, University of Stellenbosch, Stellenbosch, Western Cape, South Africa
3 Institute of Sports Medicine, Free University of Berlin, Berlin, Berlin, Germany
* To whom correspondence should be addressed. E-mail: alexstahn{at}yahoo.com.
Most studies employing bioelectrical impedance analysis (BIA) for estimating appendicular skeletal mass using descriptive BIA-models rely on statistical rather than biophysical principles. The aim of the present study was to evaluate the feasibility of estimating arm and leg muscle volume (MV) based on multiple bioimpedance measurements and using a recently proposed mathematical model and to compare this technique to conventional segmental BIA at high and low frequencies. MV of the arm and leg, respectively, was determined in 15 young, healthy, active men [age 22±2 (SD) yr, total body fat 15.6 ±5.1%] by magnetic resonance imaging (MRI) and BIA using a conventional and new bioimpedance model. MRI-determined MV for leg and arm was 6268±1099 and 1173±172 cm3, respectively. Estimated MV by the new BIA-model [leg: 6294±1155 cm3 (50 kHz), 6278±1103 cm3(500 kHz); arm: 1216±172 cm3 (50 kHz), 1155±157 cm3 (500 kHz)] was not statistically different from MRI-determined MV (leg: P=0.958; arm P=0.188). The new BIA-model was superior to conventional BIA and performed best at 500 kHz for estimating leg MV as indicated by the lower relative total error [new: 3.6% (500 kHz), 5.2% (50 kHz); conventional: 7.6% (500 kHz) and 8.3% (50 kHz)]. In contrast, the new BIA-model, both at 50 kHz and 500 kHz, did not improve the accuracy for estimating arm MV [new: 10.8% (500 kHz) 10.6% (50 kHz); conventional: 11.8% (500 kHz), 11.4% (50 kHz)]. It was concluded that modeling of multiple BIA measurements has advantages for the determination of lower limb muscle volume in healthy, active men.
