Vanzella, LM, Lawand, R, Shuaib, M, Oh, P, Corbett, D, and Marzolini, S. Validity of bioelectric impedance in relation to dual-energy x-ray absorptiometry for measuring baseline and change in body composition after an exercise program in stroke. J Strength Cond Res 36(12): 3273-3279, 2022-Exercise is an important strategy to improve fat-free mass (FFM) and reduce percent fat mass (FM%). However, no study has reported on a valid, cost-effective method to measure changes in body composition after stroke. The purpose of the study is to determine the level of agreement between bioelectrical impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA) for assessing baseline and change in FFM and FM% after an exercise training intervention for individuals with mobility deficits after stroke. Fat-free mass and FM% were measured by BIA and DXA at the beginning and after 6 months of participation in an exercise program for individuals with mobility deficits after stroke. Forty-two subjects after stroke were included. Overall, Bland-Altman plots revealed that BIA overestimated the baseline FFM and FM% by only -0.4 ± 1.8 kg and -2.8 ± 1.8%, respectively. BIA underestimated changes in FFM by 0.33 ± 0.45 kg and overestimated changes in FM% by -0.40 ± 0.68%. The 95% CI of the mean bias for baseline FFM was -7.1 to 6.3 kg and -11.8 to 6.0% for FM%, demonstrating good agreement. The 95% CI for the change in FFM was -3.8 to 4.5 kg and -5.0 to 4.2% for FM%, which reflected good agreement. BIA is a good tool for assessing qualitative baseline and change in FFM and FM%. Body composition is important for the prescription and evaluation of rehabilitation programs designed for individuals after stroke. Our results provide clinicians and researchers with a better understanding of the utility of BIA to measure body composition at baseline and in response to exercise interventions in this population.
Trial registration: ClinicalTrials.gov NCT01712724.
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