Evaluation of Multifrequency Bioelectrical Impedance Analysis in Assessing Body Composition of Wrestlers

Body Composition Changes and Factors Influencing the Total Weight Loss Rate After Laparoscopic Sleeve Gastrectomy

Objectives: While the effectiveness of metabolic/bariatric surgery has been confirmed, understanding the factors associated with weight loss is paramount for providing guidance in postoperative treatment strategies. Here, we aimed to examine the factors associated with long-term maintenance of weight loss after laparoscopic sleeve gastrectomy (LSG). Methods: This prospective observational cohort included patients who underwent LSG at a single academic health center between January 2017 and June 2022. We examined their body composition using InBody 720 or 770 and analyzed the factors associated with the percentage of total weight loss (%TWL) for 24 months. Results: The median body mass index (BMI) was 38.8 (interquartile range [IQR]: 35.6-46.7) preoperatively, 32.7 kg/m2 (IQR: 28.2-38.7) at 12 months postoperatively, and 33.9 kg/m2 (IQR: 29.1-40.1) at 24 months postoperatively. The lowest BMI was observed at 12 months (p < 0.001 vs. preoperative), followed by a significant increase at 24 months (p = 0.003). However, BMI remained significantly lower at 24 months than preoperatively (p < 0.001). The skeletal muscle mass to fat mass ratio (SMM/FM) was 0.59 (IQR: 0.50-0.71) preoperatively, 0.79 (IQR: 0.58-1.26) at 12 months, and 0.70 (IQR: 0.54-1.05) at 24 months, peaking at 12 months (p < 0.001 vs. preoperative) and decreasing significantly by 24 months (p < 0.001). Nevertheless, the SMM/FM ratio at 24 months remained higher than preoperative values (p < 0.001). Median body weight and %TWL were 86.0 kg and 15.6%, respectively, at 24 months after LSG. The SMM/FM ratio at 12 months was positively correlated with %TWL at 24 months after adjusting for age and sex. Conclusions: The effects of LSG persisted for up to 24 months postoperatively. The SMM/FM ratio 12 months after LSG was associated with the rate of weight loss at 24 months.

The extracellular-to-total body water ratio reflects improvement in the activities of daily living in patients who experienced acute stroke

OBJECTIVES

To determine the relationship between bioelectrical impedance analysis (BIA) parameters, including the extracellular water-to-total body water ratio (ECW/TBW), and the activities of daily living (ADL) improvement, in patients who experienced acute stroke.

MATERIALS AND METHODS

This retrospective cohort study included 307 patients (mean age, 72 years; 39 % female) who experienced acute stroke and were admitted to the stroke unit of the Nippon Medical School Hospital (Bunkyo-ku, Tokyo, Japan) between April 2021 and March 2022. The Functional Independence Measure (FIM) was assessed at initial rehabilitation and discharge, and FIM effectiveness was calculated as ADL improvement in the participating acute care hospitals. BIA markers included the skeletal muscle mass index (SMI), phase angle (PhA), and ECW/TBW. Multiple linear regression models were used to estimate the relationship between the FIM effectiveness and each BIA marker.

RESULTS

The mean (±SD) FIM effectiveness was 0.45 ± 0.36. The proportions of low SMI (male, <7.0 kg/m2; female, <5.7 kg/m2) and low PhA (male <5.36 degrees, female <3.85 degrees), were 48.9 % and 43.3 %, respectively. In addition, the proportions of of low (<0.36), normal (0.36-0.40), and high (>0.4) ECW/TBW ratios were 1.3 %, 78.5 %, and 20.2 %, respectively. After adjustments for demographic and clinical variables, low PhA, low ECW/TBW, and high ECW/TBW were all significantly associated with FIM effectiveness (P < 0.05), with β coefficients of -0.126, -0.089, and -0.117, respectively.

CONCLUSIONS

Low and High ECW/TBW and low PhA levels were negatively correlated with improvements in ADL. The ECW/TBW ratio may be an additional indicator of rehabilitation trainability in patients who experience acute stroke.

Effect of body fat mass loss on prognosis of radical resection for pancreatic ductal adenocarcinoma based on bioelectrical impedance analysis

BACKGROUND

Few reports have performed a prognostic analysis based on bioelectrical impedance analysis in patients with radical resection of pancreatic ductal adenocarcinoma (PDAC), and its usefulness in prognostic analysis remains unclear. This study aimed to evaluate body composition changes in patients undergoing radical resection for PDAC and analyze its impact on prognosis.

METHODS

The medical records of radical resection for patients with PDAC were retrospectively reviewed, and the parameters of body composition, including body weight, skeletal muscle mass, body fat mass (BFM), and extracellular water-total body water ratio, from preoperatively to 12 months postoperatively, for each surgical procedure were measured based on direct segmental multifrequency bioelectrical impedance analysis with an InBody 770 (InBody Inc., Tokyo, Japan) device. The clinicopathological and prognostic factors were analyzed.

RESULTS

Among 79 patients who underwent radical resection for PDAC, 36 (46%), 7 (8%), and 36 (46%) underwent pancreatoduodenectomy, total pancreatectomy, and distal pancreatectomy, respectively. The multivariate overall survival analysis demonstrated that BFM loss percentage at 1 month postoperatively ≧14% (p = 0.021), lymph node metastasis (p = 0.014), and non-adjuvant chemotherapy (p <  0.001) were independent poor prognostic factors. Multivariate analysis revealed that preoperative BFM < 12 kg and preoperative albumin < 3.5 g/dL were independently associated with BFM loss percentage at 1 month postoperatively ≧14% (p = 0.021 and p = 0.047, respectively).

CONCLUSIONS

Loss of BFM in the early postoperative period may have a poor prognosis in radical resection of PDAC.

Association between nutritional status, body composition, and fitness level of adolescents in physical education in Casablanca, Morocco

Aim

This study aims to analyze and compare dietary intake, as well as to examine the associations between energy intake in terms of macronutrients, body composition, and physical fitness (PF) specifically cardiorespiratory endurance (CE) among a sample of young adolescents aged 15 to 18 years, who participate in physical education and sports sessions in public schools in Casablanca, Morocco.

Materials and methods

A total of 311 participants, including 156 girls and 154 boys, were included in the study. Each participant maintained a food diary for 3 days during the same study week. Additionally, body composition measurements were taken using bioelectrical impedance analysis (BIA). The PF was assessed using the validated mini-Cooper test (6 min).

Results

The results show that the participants had an average total energy intake of 2386.7 ± 492.7 kcal. A significant difference was observed between boys and girls, with average energy intakes of 2468.8 ± 531.1 kcal and 2304.0 ± 437.0 kcal, respectively. These dietary intakes were significantly lower than their needs and nutritional recommendations. The associations of nutritional status, sex, body mass index (BMI) and physical fitness (PF) were tested and a positive correlation was observed following an adequate intake of carbohydrates (CHO) and proteins on Vo2max, while a negative association was observed with regard to Body fat for both sexes. Boys exhibit significantly better PF than girls (p < 0.01). Obese participants had the lowest PF and an unbalanced nutritional status, the adolescents with a normal weight p < 0.01 displayed a high level of PF compared to individuals in other weight categories.

Conclusion

The PF is significantly associated with macronutrient intake status and body composition, especially BMI and BF. The Underweight, overweight, and obese students demonstrated poorer performance in physical fitness indices compared to normal-weight. Adolescents adhering to recommended CHO and protein intake levels tend to exhibit enhanced physical fitness. Implementing strategies to encourage students to maintain a balanced diet and engage in regular physical exercise is essential.

Validation of skinfold equations and alternative methods for the determination of fat-free mass in young athletes

Intoduction

To cross-validate skinfold (SKF) equations, impedance devices, and air-displacement plethysmography (ADP) for the determination of fat-free mass (FFM).

Methods

Male and female youth athletes were evaluated (n = 91[mean ± SD] age: 18.19 ± 2.37 year; height: 172.1 ± 9.8 cm; body mass: 68.9 ± 14.5 kg; BMI: 23.15 ± 3.2 kg m-2; body fat: 19.59 ± 6.9%) using underwater weighing (UWW), ADP, and SKF assessments. A 3-compartment (3C) model (i.e., UWW and total body water) served as the criterion, and alternate body density (Db) estimates from ADP and multiple SKF equations were obtained. Validity metrics were examined to establish each method's performance. Bioelectrical impedance analysis (BIA), bioimpedance spectroscopy (BIS), and the SKF equations of Devrim-Lanpir, Durnin and Womersley, Jackson and Pollock (7-site), Katch, Loftin, Lohman, Slaughter, and Thorland differed from criterion.

Results

For females, Pearson's correlations between the 3C model and alternate methods ranged from 0.51 to 0.92, the Lin's concordance correlation coefficient (CCC) ranged from 0.41 to 0.89, with standard error of the estimate (SEE) ranges of 1.9-4.6 kg. For SKF, the Evans 7-site and J&P 3 Site equations performed best with CCC and SEE values of 0.82, 2.01 kg and 0.78, 2.21 kg, respectively. For males, Pearson's correlations between the 3C model and alternate methods ranged from 0.50 to 0.95, CCC ranges of 0.46-0.94, and SEE ranges of 3.3-7.6 kg. For SKF, the Evans 3-site equation performed best with a mean difference of 1.8 (3.56) kg and a CCC of 0.93.

Discussion

The Evans 7-site and 3-site SKF equations performed best for female and male athletes, respectively. The field 3C model can provide an alternative measure of FFM when necessary.

Assessment of Standing Multi-Frequency Bioimpedance Analyzer to Measure Body Composition of the Whole Body and Limbs in Elite Male Wrestlers

We investigated differences in body composition measurements for the whole body and limb segments in elite male wrestlers between results of multi-frequency bioelectrical impedance analyses (MF_BIA) and dual energy X-ray absorptiometry (DXA). Sixty-six elite male wrestlers from Taiwan were recruited. Wrestlers' body fat percentage (PBF_WB), whole body fat-free mass (FFM_WB), whole body lean soft tissue mass (LSTM_WB), and fat-free mass of arms, legs and trunk (FM_Arms, FFM_Legs, FFM_Trunk) were measured by MF_BIA and DXA, and analyzed using Pearson correlation coefficient and Bland-Altman plot. Correlations of FFM_WB, LSTM_WB, and PBF_WB between devices were 0.958, 0.954, and 0.962, respectively. Limits of agreement (LOA) of Bland-Altman plot were -4.523 to 4.683 kg, -4.332 to 4.635 kg and -3.960 to 3.802%, respectively. Correlations of body composition parameters FFM_Arms, FFM_Legs and FFM_Turnk between devices in each limb segment were 0.237, 0.809, and 0.929, respectively; LOAs were -2.877 to 2.504 kg, -7.173 to -0.015 kg and -5.710 to 0.777 kg, respectively. Correlation and consistency between the devices are high for FFM, LSTM and PBF but relatively low for limb segment FFM. MF_BIA may be an alternative device to DXA for measuring male wrestlers' total body composition but limb segment results should be used cautiously.

Reliability of Multifrequency Bioelectrical Impedance Analysis to Quantify Body Composition in Patients After Musculoskeletal Trauma

BACKGROUND

Changes in body composition, especially loss of lean mass, commonly occur in the orthopedic trauma population due to physical inactivity and inadequate nutrition. The purpose of this study was to assess inter-rater and intra-rater reliability of a portable bioelectrical impedance analysis (BIA) device to measure body composition in an orthopedic trauma population after operative fracture fixation. BIA uses a weak electric current to measure impedance (resistance) in the body and uses this to calculate the components of body composition using extensively studied formulas.

METHODS

Twenty subjects were enrolled, up to 72 hours after operative fixation of musculoskeletal injuries and underwent body composition measurements by two independent raters. One measurement was obtained by each rater at the time of enrollment and again between 1-4 hours after the initial measurement. Reliability was assessed using intraclass correlation coefficients (ICC) and minimum detectable change (MDC) values were calculated from these results.

RESULTS

Inter-rater reliability was excellent with ICC values for body fat mass (BFM), lean body mass (LBM), skeletal muscle mass (SMM), dry lean mass (DLM), and percent body fat (PBF) of 0.993, 0.984, 0.984, 0.979, and 0.986 respectively. Intra-rater reliability was also high for BFM, LBM, SMM, DLM, and PBF, at 0.994, 0.989, 0.990, 0.983, 0.987 (rater 1) and 0.994, 0.988, 0.989, 0.985, 0.989 (rater 2). MDC values were calculated to be 4.05 kg for BFM, 4.10 kg for LBM, 2.45 kg for SMM, 1.21 kg for DLM, and 4.83% for PBF.

CONCLUSION

Portable BIA devices are a versatile and attractive option that can reliably be used to assess body composition and changes in lean body mass in the orthopedic trauma population for both research and clinical endeavors. Level of Evidence: III.

Characteristics and Patient Reported Outcome Measures in Lipedema Patients-Establishing a Baseline for Treatment Evaluation in a High-Volume Center

Lipedema patients suffer not only from visual stigma but also reduction in their quality of life through pain and performance loss in daily life. In clinical practice, it is still difficult to reliably diagnose the disease. This study aims to provide further insights into the characteristics of lipedema patients of all stages and provide a baseline prior to surgery for a surgical treatment evaluation by means of patient-reported outcome measures. Methods: Patients completed a lipedema-specific questionnaire containing 50 items, the World Health Organization Quality of Life BREF (WHOQOL-BREF) and the Patient Health Questionnaire 9 (PHQ-9). The data were analyzed using SPSS statistics 27. Patients who had already received liposuction were excluded. Results: Five hundred and eleven patients were included, of whom 337 completed the PHQ9 and 333 completed the WHOQOL-BREF questionnaires. The general characteristics of lipedema patients, especially the daily symptoms, are described. Previous observations, such as the frequent occurrence of hypothyroidism and the low rate of type 2 diabetes, were confirmed. Over 49% suffer from severe impairments in their jobs, whereby the disease shows a familial accumulation. The results of the WHOQOL-BREF and the PHQ-9 suggest a high level of mental stress. Discussion: As surgical intervention in lipedema patients is gaining traction, its effects should be well-documented. Therefore, a comprehensive baseline needs to be established prior to surgical treatment. The psychological components are just as important as the inclusion of daily impairments.

Fat-Free Mass Index, Visceral Fat Level, and Muscle Mass Percentage Better Explain Deviations From the Expected Value of Aortic Pressure and Structural and Functional Arterial Properties Than Body Fat Indexes

Bioelectrical impedance analysis (BIA)-derived indexes [e.g., fat (FMI) and fat-free mass indexes (FFMI), visceral fat level (VFL)] are used to characterize obesity as a cardiovascular risk factor (CRF). The BIA-derived index that better predicts arterial variability is still discussed.

Consistency of the estimated target weights and ECW/TBW using BIA after hemodialysis in patients between standing and lying-down positions

Background

As hemodialysis is administered with the patient lying down, the distribution of body fluid is stable in the lying position, which is why this position is recommended for bioimpedance analysis (BIA). Although the InBody S10 is widely used for hemodialysis patients in the lying position, clinicians must make the measurements in person. In contrast, patients can use the InBody 770 to obtain measurements by themselves in the standing position, which may be more convenient. Therefore, this study compared the measurements of hemodialysis patients’ estimated target weight and ECW/TBW obtained lying down using the S10 to those obtained in the standing position using the 770.

Methods

This study was conducted among maintenance hemodialysis patients at Chuncheon Sacred Heart Hospital in October 2020. Measurements from 56 patients before and after hemodialysis were obtained using the 2 machines. Each (S10 or 770) estimated target weight, both pre- and post-hemodialysis, was considered ideal when the ECW/TBW ratio was 0.380. R² was calculated and the Bland-Altman test was performed.

Results

The patients’ median age was 64 years old, and 51% were men. The actual ultrafiltration was 2 kg, and the mean TBW change measured using the InBody devices was 1.5 L (R² = 0.718) for the S10 and 1.7 L (R² = 0.616) for the 770. The estimated target weight at pre- and post-hemodialysis showed a remarkably high correlation with the patients’ actual pre- and post-hemodialysis weight (R² > 0.095). The correlation between these measurements (lying vs. standing) before and after hemodialysis was also very close (R² = 1.0000). In addition, ECW/TBW had a good correlation (R2 ≥ 0.970) The Bland-Altman test of dry weight and ECW/TBW yielded similar results.

Conclusions

This study showed that patients’ estimated target weights in the lying position using the InBody S10 device and in the standing position using the InBody 770 device were consistent in both pre- and post-hemodialysis states.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02737-3.

Relationship between Seasonal Changes in Food Intake and Energy Metabolism, Physical Activity, and Body Composition in Young Japanese Women

We investigated seasonal changes in food intake, energy metabolism, and physical activity (PA) and explored their associations with body composition. In total, 28 women aged 20−23 years in the Kansai area of Japan participated in this year-long study spanning the winter, spring, and summer seasons. A dietary investigation was performed using the weight recording method, and the amount of histidine in the diet, which may be related to the regulation of energy intake, was calculated. Resting metabolic rate (RMR), body composition, and PA were measured using indirect calorimetry, bioelectrical impedance analysis, and uniaxial accelerometry, respectively. The results showed that energy intake was highest in winter, decreased significantly with increasing temperature, and decreased by 25% in summer. As the intake of histidine in the diet did not increase in summer, it did not seem to be involved in the suppression of energy intake. RMR was highest in winter and decreased significantly in summer by 20%. The amount of PA was low in winter, increased significantly in the spring, and decreased again in summer. Body weight increased in winter, with an accumulation of fat in the trunk and arms, and decreased in summer, with a reduction in the amount of fat. Greater energy intake and less PA in winter induced an increment in body weight despite the increase in RMR. There were no significant changes in lean body mass between the seasons; however, the muscle weight of the lower limbs increased significantly in spring and in summer compared with that in winter (p < 0.001). Thus, seasonal changes in food intake, energy metabolism, and PA occur, with resultant changes in the body composition under comfortable air-conditioned environments.

Assessment of anthropometric and body composition characteristics of elite Turkish wrestlers

Study aim: The aim of the study was to determine the anthropometric characteristics of elite Turkish wrestlers according to their weight categories.

Material and methods: In this study, 21 elite male wrestlers (age 22.9 ± 4.0) have been examined according to three weight categories: Light weight, middle weight, heavy weight. Height, weight, arm and calf girth, humerus and femur width, skinfolds (triceps, subscapular, calf, supraspinale) were measured. Arm anthropometry (upper arm muscle area, upper arm fat area, upper arm fat index), somatotype (Heath-Carter somatotype method), and body composition (bio-impedance analysis) were determined.

Results: In the light weight wrestlers, body fat was 9.95% and somatotype 2.15–6.68–1.62; in the middle weight wrestlers, body fat was 11.79% and somatotype 2.83–6.83–1.01; in the heavy weight wrestlers, body fat was 18.63% and somatotype 4.10–8.13–0.53 was determined. While the endomorphy component of the light weight wrestlers was significantly lower than the middle weight and heavy weight wrestlers (p < 0.017), the ectomorphy component was significantly higher than the heavy weight wrestlers (p < 0.05). Fat free mass differed significantly between the three weight categories (p < 0.017), while body fat was higher in heavy weight than both light weight and middle weight (p < 0.017). The weight showed a significant and positive relationship with all anthropometric and body composition values except AFI and ectomorphy (p < 0.05 with mesomorphy, p < 0.01 with others).

Conclusions: As a result of the study, it was determined that wrestlers have anthropometric characteristics specific to their weight categories. While the light weight wrestlers show a balanced mesomorph structure, the heavy weight wrestlers have adapted to the endomorphic mesomorph body type with the increase in fat and fat free mass.

Distribution of dietary protein intake in daily meals influences skeletal muscle hypertrophy via the muscle clock

The meal distribution of proteins throughout the day is usually skewed. However, its physiological implications and the effects of better protein distribution on muscle volume are largely unknown. Here, using the two-meals-per-day feeding model, we find that protein intake at the early active phase promotes overloading-induced muscle hypertrophy, in a manner dependent on the local muscle clock. Mice fed branched-chain amino acid (BCAA)-supplemented diets at the early active phase demonstrate skeletal muscle hypertrophy. However, distribution-dependent effects are not observed in ClockΔ19 or muscle-specific Bmal1 knockout mice. Additionally, we examined the relationship between the distribution of proteins in meals and muscle functions, such as skeletal muscle index and grip strength in humans. Higher muscle functions were observed in subjects who ingested dietary proteins mainly at breakfast than at dinner. These data suggest that protein intake at breakfast may be better for the maintenance of skeletal muscle mass.

Combining Anthropometry and Bioelectrical Impedance to Predict Body Fat in Female Athletes

CONTEXT

Accurate methods for predicting percent body fat in female athletes are needed for those who lose weight for competition. Methods mandated by sports-governing bodies for minimal weight determination in such athletes lack validation.

OBJECTIVE

To determine whether combining anthropometry (skinfolds, SF) and bioelectrical impedance analysis (BIA) in a 3 component model (3C) would improve the prediction of percentage body fat (%Fat) in female athletes. Secondarily, the Slaughter skinfold equation was evaluated. We hypothesized that compared to outcomes for SF or BIA alone, 3C-determined %Fat would not differ from our criterion method (accuracy) and would be a stronger predictor (higher r2) of the criterion.

DESIGN

Cross sectional.

SETTING

Laboratory-based study during the pre-season for collegiate sport.

PARTICIPANTS

Female athletes (n=18 D1 NCAA) recruited from swim and gymnastic teams.

MAIN OUTCOME VARIABLES

%Fat based on a four-compartment (4C) criterion incorporating body density (air displacement plethysmography), total body water (D2O dilution), and bone mineral mass (DEXA) compared to predicted %Fat using SF alone (Slaughter equation), bioelectrical impedance analysis (single frequency for TBW estimate) and combined skinfolds and BIA (3C).

RESULTS

Regression revealed that for %Fat using the criterion 4C, the highest adjusted coefficient of determination and lowest prediction error (r2 ±standard error of estimate) was 3C (r2=0.87 ±2.8%) followed by BIA (r2=0.80 ±3.5%) and SF (r2=0.76 ± 3.8%) (for all, p<0.05). Means differed for %Fat determined using BIA (26.6 ±7.5) and 3C (25.5 ±7.2) vs. the 4C (23.5 ±7.4) (ANOVA and post hoc p<0.05). The SF estimate (24.0 +7.8) did not differ from the 4C value.

CONCLUSIONS

Combining SF and BIA might improve the prediction and lower the prediction error for determining %Fat in female athletes compared to SF or BIA separately. Regardless, the Slaughter skinfold equation appeared accurate for determining the mean %Fat in these female athletes.

Evaluation of Fluid Loss and Customary Fluid Intake among a Selected Group of Young Swimmers: A Preliminary Field Study

This study aimed to assess fluid loss (FL) and customary fluid intake (FI) during a training session, and the relationship between FL and total body water (TBW) content in a selected group of young swimmers. The study involved 17 (seven females, 10 males) individuals whose anthropometric and body composition analyses and FI during training units were carried out. The total average FI and total actual FL oscillated around 531 mL and −513 mL for the whole study group (469 mL and −284 mL for females, 574 mL and −674 mL for males). The dependent and independent sample t-tests, the Cohen’s d effect size and Pearson’s correlation coefficient were analysed. Significant differences were observed between pre-workout and post-workout body weights after training without FI in the whole group (66.5 kg vs. 66.0 kg, p < 0.001, d = 0.06), in females (61.2 kg vs. 60.9 kg, p = 0.015, d = 0.04) and males (70.3 kg vs. 69.6 kg, p < 0.001, d = 0.9). For the TBW content and fat-free mass (FFM) before and after training, significant differences were observed only in males (TBW: 43.8 L vs. 43.2 L, p = 0.002, d = 0.14; and 62.4% vs. 61.7%, p < 0.001, d = 0.36; FFM: 59.8 kg vs. 59.1 kg, p = 0.002, d = 0.12). Moreover, the relationship between the actual FL and TBW before training was observed in the whole (mL vs. %: r = −0.64, p = 0.006; mL vs. L: r = −0.84, p < 0.001) and the male group (mL vs. L: r = −0.73, p = 0.017). These results indicated FL in young swimmers during training and the relationship between FL and pre-training TBW content, which suggests that it is important to also pay special attention to effective hydration procedures before and during training in aquatic environments.

Cardiorespiratory and muscle oxygenation responses to low-load/high-repetition resistance exercises in COPD and healthy controls

Single-limb exercises have been used as a strategy to improve aerobic exercise tolerance in patients with chronic obstructive pulmonary disease (COPD) by alleviating the cardiopulmonary demand. We asked whether this strategy would also apply to cardiorespiratory demand and amount of work performed during single-limb and two-limb low-load/high-repetition resistance exercises in 20 patients with COPD [forced expiratory volume in 1 s (FEV1) = 1.0 liters, 38% of predicted] and 15 age-, sex-, and activity-matched healthy controls. Peak ventilation, peak oxygen consumption (V̇o2), and peak heart rate (HR) were assessed to document cardiorespiratory demand during shoulder flexion and knee extension exercises while exercise tolerance was assessed by the total amount of work achieved. In addition, changes in myoglobin-deoxyhemoglobin level (Δdeoxy-[Hb/Mb]) were measured during single-limb knee extension. In COPD, single-limb shoulder flexion and knee extension elicited higher localized workloads than two-limb exercises (21 and 24% higher workloads for the former exercise) while cardiopulmonary demand was 8–16% higher during two-limb exercises. When expressed as a percentage of peak values achieved during incremental cycle ergometry, peak V̇O2 and HR were similarly high during single-limb shoulder flexion and knee extension exercises, representing 90% of peak HR and 60% of peak V̇O2. Apart from single-limb knee extension, cardiorespiratory demand per kilogram work during low-load/high-repetition knee extension and shoulder flexion exercises was higher in patients with COPD than in healthy controls (range 27–122%, P < 0.0125). Δdeoxy-[Hb/Mb] of the quadriceps during knee extension was similar between the two groups, while Δdeoxy-[Hb/Mb] per kilogram work was higher in patients with COPD. We conclude that 1) in patients with COPD, single-limb exercises resulted in lower peak cardiorespiratory demand as well as higher localized workloads compared with two-limb exercises; 2) compared with healthy controls, the cardiorespiratory demand, either expressed per unit of work or relative to peak capacity, was higher in patients with COPD than in controls during low-load/high-repetition resistance exercises, irrespective of the involvement of one or two limbs or of the upper or lower extremity; 3) quadriceps muscle deoxygenation per unit of work during low-load/high-repetition knee extension was increased in COPD compared with controls; and 4) single- and two-limb low-load/high-repetition knee extension and shoulder flexion resistance exercises imposed a similar burden on the cardiorespiratory system, resulting in a higher cardiorespiratory demand per kilogram work performed during shoulder flexion compared with knee extension, in both COPD and healthy controls.

NEW & NOTEWORTHY In chronic obstructive pulmonary disease (COPD), single-limb knee extension and shoulder flexion resulted in a lower peak cardiorespiratory response as well as larger localized exercise workloads compared with two-limb exercises. Cardiorespiratory and quadriceps deoxygenation cost per kilogram work was greater in COPD compared with healthy controls, despite similar acute responses. Compared with knee extension, shoulder flexion imposed a similar burden on the cardiorespiratory system in patients with COPD and healthy controls.

National Athletic Trainers' Association Position Statement: Fluid Replacement for the Physically Active

OBJECTIVE

  To present evidence-based recommendations that promote optimized fluid-maintenance practices for physically active individuals.

BACKGROUND

  Both a lack of adequate fluid replacement (hypohydration) and excessive intake (hyperhydration) can compromise athletic performance and increase health risks. Athletes need access to water to prevent hypohydration during physical activity but must be aware of the risks of overdrinking and hyponatremia. Drinking behavior can be modified by education, accessibility, experience, and palatability. This statement updates practical recommendations regarding fluid-replacement strategies for physically active individuals.

RECOMMENDATIONS

  Educate physically active people regarding the benefits of fluid replacement to promote performance and safety and the potential risks of both hypohydration and hyperhydration on health and physical performance. Quantify sweat rates for physically active individuals during exercise in various environments. Work with individuals to develop fluid-replacement practices that promote sufficient but not excessive hydration before, during, and after physical activity.

Segmental bioelectrical impedance analysis (SBIA) and blood rheology: Reducing the gap between in vivo and in vitro?

Bioelectrical impedancemetry (BIA) has been used to evaluate hematocrit and red cell aggregability in vitro but whole body impedance measurements are also correlated to some hemorheologic factors, suggesting a relationship between viscosity factors and electric properties of blood. We repeatedly reported correlations with whole body BIA and hematocrit, whole blood viscosity and plasma viscosity, red cell rigidity and RBC aggregation. The SBIA Inbody 770 modelizes body as 5 cylinders and measures impedance at 1, 5, 50, 250, 500, and 1000 kHz. With the SBIA we found that hematocrit is best correlated to leg reactance at 50 kHz but also to leg impedance at 1 and 5 kHz and trunk reactance. RBC aggregation "M" is best correlated to arm reactance at 5 kHz but also to most measurements of segmental impedance (28 correlations found). RBC aggregation "M1" is best correlated to arm reactance at 5 kHz and to 19 other impedance measurements. A predictive equation for "M" from the mean between the two arm reactances at 5 kHz (maXc5) is found: M = 2.1845maXc5-23.958 (r = 0.665, p < 0.001) that provides a satisfactory Bland-Altman plot (mean difference: 0.000524 range [-1.6;+1.6]. This study suggests that previously reported correlations between BIA and viscosity factors were not spurious, and that in a narrow cylinder such as the arm the structure of circulating blood (hematocrit, red cell aggregation) may influence the passage of an electric current by increasing reactance.

Muscle contraction velocity, strength and power output changes following different degrees of hypohydration in competitive olympic combat sports

Background

It is habitual for combat sports athletes to lose weight rapidly to get into a lower weight class. Fluid restriction, dehydration by sweating (sauna or exercise) and the use of diuretics are among the most recurrent means of weight cutting. Although it is difficult to dissuade athletes from this practice due to the possible negative effect of severe dehydration on their health, athletes may be receptive to avoid weight cutting if there is evidence that it could affect their muscle performance. Therefore, the purpose of the present study was to investigate if hypohydration, to reach a weight category, affects neuromuscular performance and combat sports competition results.

Methods

We tested 163 (124 men and 39 woman) combat sports athletes during the 2013 senior Spanish National Championships. Body mass and urine osmolality (U_OSM) were measured at the official weigh-in (PRE) and 13–18 h later, right before competing (POST). Athletes were divided according to their U_SOM at PRE in euhydrated (EUH; U_OSM 250–700 mOsm · kgH₂O⁻¹), hypohydrated (HYP; U_OSM 701–1080 mOsm · kgH₂O⁻¹) and severely hypohydrated (S-HYP; U_OSM 1081–1500 mOsm · kgH₂O⁻¹). Athletes’ muscle strength, power output and contraction velocity were measured in upper (bench press and grip) and lower body (countermovement jump - CMJ) muscle actions at PRE and POST time-points.

Results

At weigh-in 84 % of the participants were hypohydrated. Before competition (POST) U_OSM in S-HYP and HYP decreased but did not reach euhydration levels. However, this partial rehydration increased bench press contraction velocity (2.8-7.3 %; p < 0.05) and CMJ power (2.8 %; p < 0.05) in S-HYP. Sixty-three percent of the participants competed with a body mass above their previous day’s weight category and 70 of them (69 % of that sample) obtained a medal.

Conclusions

Hypohydration is highly prevalent among combat sports athletes at weigh-in and not fully reversed in the 13–18 h from weigh-in to competition. Nonetheless, partial rehydration recovers upper and lower body neuromuscular performance in the severely hypohydrated participants. Our data suggest that the advantage of competing in a lower weight category could compensate the declines in neuromuscular performance at the onset of competition, since 69 % of medal winners underwent marked hypohydration.

Head Exposure to Cold during Whole-Body Cryostimulation: Influence on Thermal Response and Autonomic Modulation

Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C±1.3°C and -8.3±0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ±0.11°C), while it only decreased at P20 (-0.14±0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF:+70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS.

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.

Parasympathetic activity and blood catecholamine responses following a single partial-body cryostimulation and a whole-body cryostimulation

The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a whole-body cold exposure induced a larger stimulation of the ANS compared to partial-body cold exposure.

Physical fitness factors to predict female Olympic wrestling performance and sex differences

To determine differences in anthropometric, body composition, physiological and neuromuscular markers between elite and amateur female wrestlers, 35 female wrestlers were assigned into 4 groups according to their body mass (light and middle weight) and their competitive level (elite and amateur): light weight (between 49 and 58 kg) in elite (n = 6) and amateur (n = 12) levels, and middle weight (between 58 and 67 kg) in elite (n = 7) and amateur (n = 10) levels. A binary logistic regression analysis was performed to identify which variables better predict female wrestling success. Elite female wrestlers were older (8-10%), had more training experience (27-29%), fat-free mass (3%), maximum strength in absolute and allometrically scaled values (13-33%), maximal muscle power (16-34%), mean and peak power during an arm crank Wingate testing in absolute and allometrically scaled values (17-23%), jumping height (2-9%) and grip (5-13%), and back isometric strength (10-13%) compared with amateur wrestlers (p < 0.05). When the results of the present research and those of a recent study performed in our laboratory with elite male wrestlers were compared, elite women presented lower (p < 0.05) maximum isometric and dynamic strength, muscle power output, and anaerobic metabolism values even when these data were normalized using allometric methods.

Physical fitness factors to predict male Olympic wrestling performance

To determine differences in maximal strength and muscle power output of the arm and leg extensor muscles, peak and mean power during a modified standing crank-arm Wingate test, running speed, muscle extensibility, and anthropometric markers between elite and amateurs wrestlers according to the weight classes system; 92 male wrestlers were assigned into 6 groups according to their body mass (light, middle and heavy weight) and their competitive level (elite and amateur): Light Weight (body mass ranged between 55 and 68 kg) in elite (LW(E), n = 18) and amateur (LW(A), n = 15) level; Middle Weight (body mass ranged between 68 and 84 kg) in elite (MW(E), n = 18) and amateur (MW(A), n = 19) level; and Heavy Weight (body mass ranged between 84 and 100 kg) in elite (HW(E), n = 10) and amateur (HW(A), n = 12) level. Elite wrestlers were older (8-12%), had more training experience (25-37%), fat-free mass (3-5%), maximal strength in absolute and relative terms (8-25%), muscle power (14-30%), mean and peak power during crank-arm Wingate testing in absolute and relative terms (13-22%), jumping height (8-17%) as well as grip (6-19%) and back strength (7-20%) compared to amateur wrestlers. However, no differences were observed between elite and amateur groups in height, body mass index, percentage of body fat, hamstring extensibility and running speed. The present results suggest that the higher absolute and relative values of maximal strength, muscle power, and anaerobic metabolism, explained in part by the differences in lean mass and neural activation patterns, will give elite wrestlers a clear advantage during the most frequently used techniques in Olympic wrestling.