Robert A. Oppliger

Blood and urinary measures of hydration status during progressive acute dehydration

PURPOSE To determine whether: a) plasma osmolarity (Posm) is sensitive to small incremental changes in hydration status, b) urine specific gravity (Usg) can accurately identify a state of euhydration, c) Usg is a sensitive indicator of a change in hydration status, and d) Usg correlates with Posm. METHODS Euhydrated (Posm = 288 +/- 4 mOsm.L-1) subjects (N = 12) were dehydrated by 5% of their body weight via exercise in the heat (40 degrees C, 20% RH). Posm, urine osmolarity (Uosm), and Usg were measured at 1%, 3%, and 5% dehydration, and 30 and 60 min of recovery (rec). Subjects consumed water in recovery equal to their loss of body weight. RESULTS Posm increased incrementally with each successive increase in percent body weight loss (%BWL). Usg was not significantly different from baseline until 3% BML. Uosm was not significantly different from baseline until 5% BWL. Usg correlated moderately (r = 0.46, P > 0.10) with Posm but reasonably well (r = 0.68, P < 0.02) with Uosm. CONCLUSIONS Posm accurately identifies a state of euhydration and is sensitive to changes in hydration status during acute dehydration and rehydration. Usg and Uosm are also sensitive to changes in hydration status but lag behind during periods of rapid body fluid turnover and therefore correlate only moderately with Posm during acute dehydration.

Hydration Testing of Athletes

AbstractDehydration not only reduces athletic performance, but also places athletes at risk of health problems and even death. For athletes, monitoring hydration has significant value in maximising performance during training and competition. It also offers medical personnel the opportunity to reduce health risks in situations where athletes engage in intentional weight loss. Simple non-invasive techniques, including weight monitoring and urine tests, can provide useful information. Bioimpedance methods tend to be easy to use and fairly inexpensive, but generally lack the precision and accuracy necessary for hydration monitoring. Blood tests appear to be the most accurate monitoring method, but are impractical because of cost and invasiveness. Although future research is needed to determine which hydration tests are the most accurate, we encourage sports teams to develop and implement hydration monitoring protocols based on the currently available methods. Medical personnel can use this information to maximise their team’s athletic performance and minimise heat- and dehydration-related health risks to athletes.

Wrestlers' minimal weight : anthropometry, bioimpedance, and hydrostatic weighing compared

The need for accurate assessment of minimal wrestling weight among interscholastic wrestlers has been well documented. Previous research has demonstrated the validity of anthropometric methods for this purpose, but little research has examined the validity of bioelectrical impedance (BIA) measurements. Comparisons between BIA systems has received limited attention. With these two objectives, we compared the prediction of minimal weight (MW) among 57 interscholastic wrestlers using three anthropometric methods (skinfolds (SF) and two skeletal dimensions equations) and three BIA systems (Berkeley Medical Research (BMR), RJL, and Valhalla (VAL]. All methods showed high correlations (r values greater than 0.92) with hydrostatic weighting (HW) and between methods (r values greater than 0.90). The standard errors of estimate (SEE) were relatively small for all methods, especially for SF and the three BIA systems (SEE less than 0.70 kg). The total errors of prediction (E) for RJL and VAL (E = 4.4 and 3.9 kg) were significantly larger than observed nonsignificant BMR and SF values (E = 2.3 and 1.8 kg, respectively). Significant mean differences were observed between HW, RJL, VAL, and the two skeletal dimensions equations, but nonsignificant differences were observed between HW, BMR, and SF. BMR differed significantly from the RJL and VAL systems. The results suggest that RJL and VAL have potential application for this subpopulation. Prediction equation refinement with the addition of selected anthropometric measurement or moderating variables may enhance their utility. However, within the scope of our study, SF and BMR BIA appear to be the most valid methods for determining MW in interscholastic wrestlers.

Wisconsin minimum weight program reduces weight-cutting practices of high school wrestlers.

OBJECTIVE Winconsin high school wrestlers were surveyed 1 year before (90W) and 2 years after (93W) a new program was implemented to restrict weight loss for competition. The Wisconsin wrestling minimal weight program (WMWP) included a minimal weight limit determined from percent body fat and a nutrition education program. DESIGN A retrospective survey of wrestlers was conducted, with schools stratified to reflect school size and quality of the wrestling program. PARTICIPANTS Respondents surveyed in 1990 included 713 wrestlers from 45 schools; 368 wrestlers from 29 of the same schools responded to an identical survey in 1993. MAIN OUTCOME MEASURES Measures of weight-cutting practices, weight-loss methods, bulimic behaviors, and nutritional knowledge. RESULTS The most weight lost (MWL), the weight lost to certify (WLC), the weekly weight cycled (WWC), the longest fast (LF), and the frequency of cutting weight (FCW) all decreased significantly (chi 2, p < 0.05) among 93W wrestlers compared with 90W wrestlers. The results for the 90W group are as follows: MWL, 3.2 kg +/- 2.6; WLC, 2.8 kg +/- 2.8; WWC, 1.9 kg +/- 1.5; LF, 20.5 hours +/- 17.2; FCW, 6.2 +/- 6.4. The results for the 93W group are as follows: MWL, 2.6 kg +/- 2.6; WLC, 2.4 kg +/- 2.9; WWC, 1.6 kg +/- 1.4; LF, 16.5 hours +/- 15.6; FCW, 4.7 +/- 6.7. Weight-loss methods, including restricting food or fluids and use of rubber suits, declined significantly (chi 2, p < 0.05). Wrestlers exhibiting more than one of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R)-related bulimic behaviors decreased by 11% (chi 2, p < 0.05), but those exhibiting all five (1.6%) remained the same. CONCLUSIONS The results suggest that the WMWP appeared to reduce unhealthy weight-loss behaviors among high school wrestlers. Other states should be encouraged to institute similar programs as recommended by the American Medical Association and the American College of Sports Medicine.

ACSM Position Stand: Weight Loss in Wrestlers

SUMMARYDespite a growing body of evidence admonishing the behavior, weight cutting(rapid weight reduction) remains prevalent among wrestlers. Weight cutting has significant adverse consequences that may affect competitive performance, physical health, and normal growth and development. To enhance th

A comparison of leg-to-leg bioelectrical impedance and skinfolds in assessing body fat in collegiate wrestlers.

A comparison of the leg-to-leg bioelectrical impedance (BIA) system and skinfold analysis in estimating % body fat in a large number of National Collegiate Athletic Association (NCAA) collegiate wrestlers was conducted. A series of 5 cross-sectional assessments, including the NCAA Division I and III Championships, were completed throughout the 1998–1999 wrestling season with samples ranging from (N = 90–274). Body density was determined from the 3 skinfold measures using the Lohman prediction equation. BIA measurements were determined using the Tanita body fat analyzer, model 305. Significant correlations between methods ranging from (r = 0.67–0.83, p < 0.001) and low standard error of estimates (SEE) for % body fat ranging from 2.1–3.5% were found throughout the 5 assessment periods. This preliminary study demonstrated that the leg-to-leg bioelectrical impedance system accurately estimated % body fat when compared to skinfolds in a diverse collegiate wrestling population.

Patients’ views about physician participation in assisted suicide and euthanasia

OBJECTIVE: To elucidate the effect of physician participation in physician-assisted suicide and euthanasia on the physician-patient relationship.DESIGN: A questionnaire administered to 228 adult patients.SETTING: A university-based family practice training program.PATIENTS/PARTICIPANTS: We approached 230 individuals of at least 18 years of age who were patients in the study practice. These individuals were selected on the basis of age and gender to ensure a heterogeneous study population. Of these, 228 agreed to participate and completed the questionnaire.RESULTS: The majority of subjects felt that a physician who assists with suicide or performs euthanasia is capable of being a caring person (91% and 88%, respectively) and would still be able to offer emotional support to surviving family members (85% and 76%, respectively). Most also felt that a physician assisting in suicide or euthanasia would be as trustworthy as a nonparticipating physician to care for critically ill patients (90.5% and 84.6%, respectively). Five percent “likely would not” continue to see their physician if it was known that he or she assisted in suicide and 7.8% “likely would not” continue seeing their physician if it was known that this physician performed euthanasia. No individuals stated that they “definitely would not” continue seeing their doctor under either circumstance. Individuals who supported the ideas of physician-assisted suicide and euthanasia were more likely to think that a physician who assisted with suicide and euthanasia could perform well in the tasks noted above and would be more likely to continue seeing such a physician (p=.001)CONCLUSION: Participating in physician-assisted suicide and euthanasia does not markedly adversely affect the physician-patient relationship.

Cross-validation of the NCAA method to predict body fat for minimum weight in collegiate wrestlers.

ObjectiveIn 1998, the National Collegiate Athletic Association (NCAA) adopted a new rule that required minimum weight testing for collegiate wrestlers. The objective of the study was to cross-validate the method used by the NCAA to estimate minimum weight in collegiate wrestlers. DesignThe NCAA skinfold equation was cross-validated against a criterion value from hydrostatic weighing (HW). SettingThe subjects were tested at the Universities of Wisconsin and Iowa. SubjectsA sample of 93 college wrestlers from the Universities of Wisconsin and Iowa (mean ± SD; age = 20.20 ± 1.67 years, height = 171.98 ± 6.63 cm, weight = 74.44 ± 11.48 kg) were studied. Outcome MeasuresCross-validation included analysis of the standard error of estimate (SEE), total error (TE), and residual plots. ResultsThe mean body fat from the NCAA prediction (10.61 ± 3.58%) was not significantly different than HW (9.70 ± 3.95%). The SEE was low (2.32%), and the TE was low (2.49%). The difference in methods was related to the size of the HW value. The residual plot (y = −0.26x + 3.45, R2 = 0.198) suggests that fat is overestimated in the leaner wrestlers and underestimated in fatter wrestlers. ConclusionThe authors found the NCAA method to be a valid predictor of body fat in this sample of 93 collegiate wrestlers under the conditions of the study. Although some bias was seen across the range of fatness, these data support the NCAA method to estimate body fat in college wrestlers for establishment of minimum weight.

Iowa wrestling study: cross-validation of the Tcheng-Tipton minimal weight prediction formulas for high school wrestlers.

Previous research by Tcheng and Tipton developed two prediction equations appropriate for the estimation of minimal weight for high school wrestlers. The purpose of this investigation was to cross-validate these equations using densitometric estimates of minimal weight. Skeletal dimension measurements and hydrostatic weighing were completed on 220 Iowa high school wrestlers at various times in and out of season. High concurrent validity (r = 0.93) and small residual errors (less than 0.33 kg) were observed when compared to densitometric estimates. Regression weights were of similar magnitude to those from the previous study. Two new prediction models were tested. Model II enhanced the multiple R over previous equations to 0.962 and decreased the SEE by 25% (0.55 kg). The equation was: Minimal Weight (lbs) = 0.49 x Current Weight (lbs) + 1.65 x Height (inches) + 1.81 x Chest Diameter (cm) + 6.70 x Right Wrist Diameter (cm) + 1.35 x Chest Depth (cm) - 156.56. It was concluded that the Tcheng-Tipton equations or the new models could be used as valid indicators of a minimal weight for scholastic wrestlers.