A Comparison of Methods Used to Determine Percent Body Fat, Minimum Wrestling Weight, and Lowest Allowable Weight Class.

ABSTRACT: Cutrufello, PT, Landram, MJ, Venezia, AC, and Dixon, CB. A comparison of methods used to determine percent body fat, minimum wrestling weight, and lowest allowable weight class. J Strength Cond Res 35(3): 633-637, 2021-The National Collegiate Athletic Association's weight management program allows for the use of skinfold measurements (SF), air displacement plethysmography (ADP), and hydrostatic weighing in the assessment of percent body fat (%BF) and determination of a wrestler's minimum wrestling weight (MWW). Dual energy x-ray absorptiometry (DXA) and ultrasound (US) may offer alternative assessment methods. The purpose of this study was to examine %BF, MWW, and the lowest allowable weight class as determined by SF, ADP, DXA, and US. Thirty-three college-aged men (20.8 ± 1.1 years) participated. Urine specific gravity (Usg) was assessed to ensure proper hydration (1.006 ± 0.006). Percent body fat and MWW were then determined using the 4 assessment methods. Each method was significantly different from one another (p < 0.05) with the exception of ADP compared with SF (17.6 ± 7.1% vs. 17.4 ± 6.3%, p = 1.000) and DXA compared with US (20.5 ± 6.2% vs. 19.2 ± 7.5%, p = 0.124). DXA (68.6 ± 7.1 kg) and US (69.3 ± 6.0 kg) determined the lowest MWW, whereas those determined by SF (70.8 ± 6.8 kg) and ADP (70.9 ± 6.6 kg) were significantly greater (p< 0.05). The SEEs for MWW when compared with SF were 3.2, 3.4, and 2.4 kg for ADP, DXA, and US, respectively. Compared with SF, DXA and US would allow wrestlers to certify at a lower weight class 64 and 33% of the time, respectively. When comparing the approved methods (SF and ADP), approximately 50% of subjects would certify at a different weight class depending on the method used. The use of different methods in assessing %BF offer a wide variability in the determination of MWW.

The Effect of the Menstrual Cycle on Body Composition Determined by Contact-Electrode Bioelectrical Impedance Analyzers.

Bioelectrical impedance analysis (BIA) is a noninvasive and relatively inexpensive method of assessing body composition. Manufacturers of BIA technology recommend to avoid testing women when they perceive to be retaining water during the menstrual cycle. The purpose of the present investigation was to examine the effect of the menstrual cycle on body composition determined by contact-electrode BIA analyzers. Forty-three college-aged women volunteered to participate in this study (age=21.2 ± 1.1 years; body mass index = 24.0 ± 3.7 kg/m2). Subjects had their body composition assessed using four different contact-electrode BIA analyzers during the following menstrual cycle phases: menstrual, follicular, early and late luteal. Regardless of the BIA analyzer used for the assessment, no significant differences in body composition measures were found between cycle phases. The results of this study indicate that the contact-electrode BIA devices used in this study can be used at any time during a woman's menstrual cycle without altering the body composition values.

Hydration assessment among marathoners using urine specific gravity and bioelectrical impedance analysis.

The present study examined the relationship between urine specific gravity (Usg), body mass (BM) and bioelectrical impedance determined variables [total body water (TBW), per cent TBW and impedance values] before and after a marathon (n = 25 men; 10 women). A significant reduction in BM (pre: 71.2 ± 12.4 kg; post: 69.6 ± 12.0 kg; p < 0.001) and an increase in Usg (pre: 1.009 ± 0.007; post: 1.018 ± 0.009; p < 0.001) was observed post-race. TBW was not significantly decreased (pre: 42.7 ± 8.0 kg; post: 42.4 ± 7.7 kg) while per cent TBW significantly increased post-race (pre: 60.0 ± 3.9%; post: 60.8 ± 3.8%; p < 0.001). Impedance values were significantly greater post-race (pre: 3288 ± 482; post: 3416 ± 492 Ω; p < 0.001). There was no correlation between the change in Usg and the change in BM or any of the bioelectrical impedance determined variables. On average, BM, Usg and impedance values appear to express changes in hydration; however, the observed changes among these variables for a given individual appear to be inconsistent with one another.

The effect of acute fluid consumption following exercise-induced fluid loss on hydration status, percent body fat, and minimum wrestling weight in wrestlers.

Acute fluid consumption (approximately 1 L) has been shown to reduce urine specific gravity (Usg) among subjects after an overnight fast, yet it is unknown if Usg may be reduced among subjects who have experienced exercise-induced fluid loss. The purpose of this study was to examine the effect of acute fluid consumption on Usg, body mass, percent body fat (%BF), and minimum wrestling weight (MWW) following an exercise-induced fluid loss protocol. National Collegiate Athletic Association coaches' perceptions of the weight certification program (WCP) were also evaluated. Twelve men wrestlers (19.8 ± 1.14 years) were tested prepractice (PRE), postpractice (POST), and 1 hour after consuming 1 L of water (PFC). Percent body fat was measured by skinfolds (SF), air displacement plethysmography (ADP), and multifrequency and leg-to-leg bioelectrical impedance analysis to calculate MWW. Urine specific gravity measurements significantly increased above PRE (1.013 ± 0.006) at the POST (1.019 ± 0.007; p = 0.017) and PFC (1.022 ± 0.008; p = 0.025) assessments; however, POST and PFC were not significantly different (p = 0.978) from one another. The %BF values were similar (p > 0.05) at each assessment point when using SF and ADP. When compared with PRE, MWW significantly reduced at the POST assessment when using SF (67.2 ± 8.4 vs. 65.7 ± 8.2 kg; p < 0.001) and ADP (66.6 ± 9.1 vs. 64.8 ± 9.0 kg; p = 0.001), reflecting the reduction in body mass observed after exercise. Forty-seven National Collegiate Athletic Association coaches completed the questionnaire and 2 central themes emerged: (a) concerns with the 1.5% weight loss plan and (b) wrestlers using strategies in an attempt to circumvent the WCP. Exercise-induced fluid loss followed by acute fluid consumption equal to 1 L was ineffective in reducing Usg.

Effect of exercise intensity on percent body fat determined by leg-to-leg and segmental bioelectrical impedance analyses in adults.

PURPOSE: We examined the impact that cycle ergometry exercise had on percent body fat (% BF) estimates when assessed using either leg-to-leg or segmental bioelectrical impedance analysis (LBIA; SBIA) and whether the intensity of the exercise bout impacts the %BF magnitude of change. METHOD: Seventy-four college-aged adults participated in this study. Participants visited the laboratory on three separate occasions. Testing included two 30-min exercise sessions (70% HR(max) and 85% HR(max)) and a 30-min no-exercise session, which served as the control. RESULTS: Following exercise, significant (p < .05) reductions in mean %BF were observed when using LBIA (70% HR(max) = 0.3%; 85% HR(max) = 0.5%) and SBIA (70% HR(max) = 0.8%; 85% HR(max) = 1.4%). The mean %BF reductions were significantly (p < .04) greater following exercise at the higher intensity for both analyzers. CONCLUSIONS: Our findings indicate that cycle exercise performed before LBIA and SBIA body composition assessment reduces mean %BF estimates. In addition, the %BF reductions were found to be larger at the higher end of the American College of Sports Medicine/American Heart Association recommended intensity range (85% HR(max)) and when the SBIA analyzer was used to conduct the assessment.

The effect of acute fluid consumption and hydration status on percent body fat and minimum wrestling weight.

The weight certification program for wrestling requires a urine-specific gravity (USG) <1.020. However, the effect of acute rehydration on percent body fat (%BF) and minimum wrestling weight (MWW) is largely unknown. We examined the effect of acute fluid consumption on %BF and MWW. Twenty-five male subjects (18-22 years) were tested in a dehydrated state (USG > 1.020; DEH), 1 hour after rehydration (USG < 1.020; REH), and on a separate day in a hydrated state (USG < 1.020; HYD) which served as the criterion. Percent body fat was determined using skinfolds (SF), air displacement plethysmography (ADP), leg-to-leg bioelectrical impedance analysis (LBIA), and multifrequency bioelectrical impedance analysis (MBIA). Regardless of hydration state, %BF values were not significantly different when using SF (DEH = 13.35 ± 4.03%; REH = 13.41 ± 3.99%; HYD = 13.47 ± 4.31%; p = 0.693) or ADP (DEH = 15.68 ± 4.69%; REH = 16.19 ± 4.57%; HYD = 15.88 ± 4.72%; p = 0.145). The MWW after fluid consumption (REH) was similar to the criterion (HYD) when using SF (REH = 72.04 ± 8.25 kg; HYD = 72.23 ± 8.15 kg; p = 1.000) and ADP (REH = 70.38 ± 8.93 kg; HYD = 70.81 ± 8.50 kg; p = 0.177) methods. Conversely, hydration state had a significant impact on LBIA (p = 0.011) and MBIA (p < 0.001) %BF values resulting in reduced MWWs. When using the SF and ADP methods to assess %BF, modest amounts of water (∼1 L) restored euhydration (<1.020) without negatively affecting %BF or MWW. Therefore, acute fluid consumption (∼1 L) may offer a safe alternative in which the weight certification program can be expedited.

Does a Physical Education Bout Alter Percent Body Fat and the Adiposity Health Risk Classification When Using Leg-to-leg Bioelectrical Impedance Analysis in Girls?

The purposes of this investigation were to determine: 1) whether a structured in-school physical education exercise bout altered the leg-to-leg bioelectrical impedance analysis (LBIA) determined percent body fat (%BF) value; and 2) whether the potential exercise-induced %BF magnitude of change altered the health risk classification of the child. Seventy-six girls (age: 12.2±1.0 yr; height: 153.9±7.5 cm; body mass: 51.9± 15.5 kg; BMI: 21.7±5.4 kg/m2) participated in this investigation. LBIA measured %BF values were obtained immediately before and within 5-min after completing a structured, in-school, physical education class. Significant reductions (p < 0.001) in mean %BF (25.0±10.2 vs. 24.4±10.3 %) were observed for the group following the physical education class. For the majority of the girls (88%), the %BF alteration was less than ± 2.0 %BF. More specifically, the %BF magnitude of change was ±1.0 %BF in 64.5% of the girls, between 1.1 and 2.0 %BF in 23.7% of the girls, and by more than 2.0 %BF in 11.8% of the girls. Regardless of the %BF magnitude of change, all girls remained in the same adiposity classification category (healthy vs. unhealthy body fat) following exercise. Adhering to the pre-test exercise guideline appears unnecessary when using LBIA to categorize the health risk of an adolescent girl.

Effect of resistance exercise on percent body fat using leg-to-leg and segmental bioelectrical impedance analysis in adults.

The purpose of this study was to examine the effect of a resistance exercise bout on percent body fat (%BF) measured by leg-to-leg and segmental bioelectrical impedance analysis (LBIA; SBIA) in adults. Eighty-six volunteers (45 women; 41 men) reported to the weight training facility on 2 separate occasions. After an initial LBIA and SBIA assessment, subjects performed 60 minutes of continuous resistance exercise, or did nothing, which served as the control. During the resistance exercise trial, subjects completed an 8-exercise circuit protocol consisting of 3 sets of 10 to 12 repetitions at 65-75% of 1 repetition maximum for each exercise. Subjects were provided with a bottle of water for consumption during both trials. Body composition was reassessed 60 minutes after baseline for comparison. For the resistance exercise trial, significant reductions (p < 0.05) in SBIA-measured %BF (women = 0.9 +/- 1.0%; men = 1.4 +/- 0.8%) and impedance (women = 22.2 +/- 17.0 Omega; men = 22.3 +/- 10.0 Omega) were observed, whereas LBIA body composition measurements remained unchanged. After the control trial, significant increases (p < 0.05) in SBIA-measured %BF (women = 0.6 +/- 0.8%; men = 0.5 +/- 0.7%) and impedance (women = 7.8 +/- 12.6 Omega; men = 4.7 +/- 8.3 Omega) and LBIA-measured %BF (women = 0.4 +/- 0.7%; men = 0.4 +/- 0.5%) were observed because of the body mass gain (approximately 300-400 g) after drinking. When using SBIA, assessments should be performed before resistance exercise to eliminate exercise-induced alterations in %BF. Conversely, resistance exercise had no effect on the LBIA measurements, and, therefore, following pretest exercise guidelines may not be necessary when this technology is used for the body composition assessment.

Evaluation of Hand-to-Hand Bioelectrical Impedance Analysis for Estimating Percent Body Fat in Young Adults.

Purposes were to (a) to examine the validity and precision of a hand-to-hand bioelectrical impedance analyzer (HBIA) and (b) to determine the effect of an acute sub-maximal aerobic exercise bout on HBIA percent body fat (%BF) measures. Forty-one young adults (21 women; 20 men) visited the laboratory for body composition assessment on two separate occasions. During the control session, %BF was assessed by HBIA twice, before and immediately after 30 min of rest, and once by air-displacement plethysmography (ADP), using the BOD POD, which was considered the criterion method for comparison. During the exercise session, HBIA %BF measurements were determined prior-to and immediately after 30 minutes of moderate-intensity treadmill exercise. HBIA significantly underestimated %BF in the total sample (mean difference (MD) = 1.4 ± 4.3%) and, when examined by gender, in the women (MD = 2.4 ± 4.1%). The standard errors of estimate (range 4.1-4.3%) also exceeded the recommended range for accuracy (<3.5%). Following exercise, there was minimal, but statistically significant reduction in HBIA-measured %BF pre- to post-exercise for the total sample (19.6 ± 6.0 vs. 19.3 ± 6.0%; p = 0.011). HBIA underestimated %BF when compared to ADP and the individual prediction error exceeded current recommendations when assessing young adults. In addition, performing sub-maximal aerobic exercise prior to the assessment decreased the %BF estimate. When one factors the exercise-induced alterations with the currently observed tendency for HBIA to underestimate %BF, it is apparent that exercise may further reduce the accuracy of this method.

The effect of acute resistance exercise on serum malondialdehyde in resistance-trained and untrained collegiate men.

The purposes of this study were to determine whether acute resistance exercise increases serum malondialdehyde (MDA) levels postexercise, and if so, whether resistance exercise training status influences the magnitude of the exercise-induced lipid peroxidation response. Twelve recreationally resistance-trained (RT) and 12 untrained (UT) men who did not have resistance exercise experience in the past year participated in this study. All subjects completed an 8-exercise circuit resistance exercise protocol consisting of 3 sets of 10 repetitions at 10 repetitions maximum for each exercise. Blood samples were obtained pre-exercise, at 5 minutes postexercise, and at 6, 24, and 48 hours postexercise. At pre-exercise, MDA (nmol.ml(-1)) averaged 3.41 +/- 0.25 (RT) and 3.20 +/- 0.25 (UT) and did not differ (p > 0.05) either between groups or over time. Creatine kinase (IU.L(-1)) was significantly (p < 0.05) elevated 5 minutes postexercise (170.6 +/- 25.8), 6 hours postexercise (290.3 +/- 34.4), 24 hours postexercise (365.5 +/- 49.9), and 48 hours postexercise (247.5 +/- 38.5) as compared with pre-exercise (126.4 +/- 20.2) for both groups. There was no difference (p > 0.05) in CK activity between groups. This study indicated that moderate-intensity whole-body resistance exercise had no effect on serum MDA concentration in RT and UT subjects.

Comparison of maximal oxygen consumption between obese black and white adolescents.

The purpose of this investigation was to determine whether maximal oxygen consumption (VO2max) differed between clinically obese black and white children and if a difference existed to determine whether it was related to hematological profiles and/or physical activity/inactivity levels. Twenty-three black and 21 white adolescents were matched for age, BMI, and Tanner stage (II-V). Body composition was determined by DEXA and CT scan. Daily physical activity/inactivity was assessed by questionnaire. VO2max was assessed using the Bruce treadmill protocol. Black participants had significantly lower VO2max and VO2maxFFM values when compared with white adolescents (26.1 +/- 4.2 versus 29.9 +/- 3.1 mL . kg(-1) . min(-1); 48.3 +/- 8.8 versus 55.6 +/- 5.2 mL . kgFFM(-1) . min(-1), respectively). Black adolescents also had significantly lower Hb concentrations ([Hb]) than white children (12.7 +/- 1.3 versus 13.4 +/- 0.7 g/dL). Black adolescents were more physically inactive than their white peers. VO2max correlated with [Hb] for the combined groups. Obese black adolescents had lower VO2max compared with white children and this difference was explained, in part, by the lower [Hb] observed in the black participants. Further investigations should study Hb flow rate (a function of [Hb] . maximal cardiac output) and physical activity/inactivity patterns in obese black and white children as it relates to VO2max.

Evaluation of the BOD POD and leg-to-leg bioelectrical impedance analysis for estimating percent body fat in National Collegiate Athletic Association Division III collegiate wrestlers.

The purpose of this study was to compare percent body fat (%BF) estimated by air displacement plethysmography (ADP) and leg-to-leg bioelectrical impedance analysis (LBIA) with hydrostatic weighing (HW) in a group (n = 25) of NCAA Division III collegiate wrestlers. Body composition was assessed during the preseason wrestling weight certification program (WCP) using the NCAA approved methods (HW, 3-site skinfold [SF], and ADP) and LBIA, which is currently an unaccepted method of assessment. A urine specific gravity less than 1.020, measured by refractometry, was required before all testing. Each subject had all of the assessments performed on the same day. LBIA measurements (Athletic mode) were determined using a Tanita body fat analyzer (model TBF-300A). Hydrostatic weighing, corrected for residual lung volume, was used as the criterion measurement. The %BF data (mean +/- SD) were LBIA (12.3 +/- 4.6), ADP (13.8 +/- 6.3), SF (14.2 +/- 5.3), and HW (14.5 +/- 6.0). %BF estimated by LBIA was significantly (p < 0.01) smaller than HW and SF. There were no significant differences in body density or %BF estimated by ADP, SF, and HW. All methods showed significant correlations (r = 0.80-0.96; p < 0.01) with HW. The standard errors of estimate (SEE) for %BF were 1.68, 1.87, and 3.60%; pure errors (PE) were 1.88, 1.94, and 4.16% (ADP, SF, and LBIA, respectively). Bland-Atman plots for %BF demonstrated no systematic bias for ADP, SF, and LBIA when compared with HW. These preliminary findings support the use of ADP and SF for estimating %BF during the NCAA WCP in Division III wrestlers. LBIA, which consistently underestimated %BF, is not supported by these data as a valid assessment method for this athletic group.

Self-regulated cycling using the Children's OMNI Scale of Perceived Exertion.

PURPOSE: An estimation and production paradigm was used to determine whether clinically normal 8- to 12-yr-old female (N = 18) and male (N = 18) children could (a) self-regulate intermittent cycle ergometer exercise using a prescribed target rating of perceived exertion (RPE), (b) discriminate between target RPEs, and (c) produce intermittent target RPEs in both an ascending and descending sequence. METHODS: Overall body RPE was assessed with the Children's OMNI Scale (0-10). Subjects underwent (a) one orientation trial, (b) one estimation (E) trial, and (c) two production (P) trials. During E, RPE was estimated each minute of a progressive cycle ergometer test. During the 3-min intermittent P trials, subjects titrated cycle brake force to produce either an RPE sequence of 2 and 6 (ascending) or 6 and 2 (descending). The P trials simulated short, intermittent exercise typical of children's play. RESULTS: Oxygen uptake (VO2) did not differ between E and P at a target RPE of 2 (0.63 versus 0.66 L x min(-1)) and 6 (1.27 vs 1.21 L x min(-1)). Heart rate (HR) did not differ between E and P at a target RPE of 2 (104.1 vs 102.6 beats.min-1) and 6 (153.7 vs 154.5 beats x min(-1)). Both VO2 and HR were higher (P < 0.01) at a target RPE-6 than -2. Responses were not affected by gender or production sequence. CONCLUSION: Young female and male children were able to use the OMNI Scale to self-regulate short-duration intermittent cycle exercise intensity.