Assessing Consumer-Grade BIA for Minimum Wrestling Weight Determination in Boys High School Wrestling

ABSTRACT: Jagim, AR, Twohey, E, Fields, JB, Shepler, C, and Jones, MT. Assessing consumer-grade BIA for minimum wrestling weight determination in boys high school wrestling. J Strength Cond Res XX(X): 000-000, 2026-Preseason weight certification in high school wrestling requires valid assessment of body fat percentage to calculate a minimum wrestling weight (MWW). Although skinfold (SKF) thickness is the standard method, bioelectrical impedance analysis (BIA) devices are widely used in school settings. The current study evaluated differences in body fat percentage (BF%), MWW, and resultant minimum weight class (MWC) between SKF and a consumer-grade multifrequency BIA (MFBIA) device. Thirty-six high school male wrestlers completed hydration assessment, weigh-in, SKF testing via a three-site model, and MFBIA assessment during a single afternoon session. Body fat percentage, fat-free mass (FFM), MWW, and resulting MWC were calculated according to state-sanctioned weight certification protocols. Estimates of BF% were higher for SKFBF% compared with the MFBIA% (SKF: 12.9 ± 4.5%; MFBIA: 10.9 ± 5.5%; p < 0.001), resulting in a mean difference of -2.1 ± 3.2% (95% CI: -3.1 to -0.9). Skinfold-derived values were lower for MWW (SKF: 62.1 ± 8.9 kg; MFBIA: 63.8 ± 10.3 kg; p < 0.001) and FFM (SKF: 57.3 ± 8.6 kg; MFBIA: 59.3 ± 9.7 kg; p < 0.001) compared with MFBIA-derived values. This resulted in a mean difference of -1.7 ± 2.4 kg (95% CI: -2.4 to -0.9) and -2.1 (95% CI: -2.76 to -1.2) for MWW and FFM, respectively. Approximately 56% of athletes (n = 20) were assigned to different MWCs depending on the method used. Although group-level %BF and MWW values were similar, the observed individual-level discrepancies indicate that the current consumer-grade MFBIA device should not be used interchangeably with the state-sanctioned SKF method for weight certification, and that BIA devices intended for regulatory use should be validated against the mandated field method or a laboratory-based criterion measure.