The objective of this work is to offer a new method of evaluation using the corporal and thoracic bioimpedance of pre-term neonate with Respiratory Discomfort Syndrome, submitted or not to the invasive mechanical ventilation. Thirty pre-term neonates with Respiratory Discomfort Syndrome were evaluated. They were admitted interned in the newborn intensive therapy unit of Hospital Universitário Evangélico de Curitiba (HUEC) from August to November of 2004. The percentage average of the gestational age in both groups was 32 weeks and the weight was 1250g. The newborn were divided into two groups, group A (15 newborns), with Respiratory Discomfort Syndrome of medium to moderate clinical repercussion, needing the invasive ventilator support. Group B (15 newborn) with light level of Respiratory Discomfort, without the need of ventilator support. The newborn of both groups were evaluated according to the Silverman-Andersen report. Which average in group A was 7 and in group B was 3. Five time speed measurement of subjects of group A were analyzed in the statistical analyses, and they were compared to an unique observation of group B. On the first measurement made in group A, it was noticed a low resistance both corporal (410) and thoracic (32,53) relative to group B. where the percentage average was 595 in the corporal resistance and 46,13 in the thoracic one. In the capacitive reactance it was noticed in the first analyses an inversely proportional behavior, and an increasing in the capacitive reactance for both corporal and thoracic in group A related to group B. As long as the newborns in group A improved clinically, a tendency in increasing the resistance values both corporal and thoracic was observed, correlating with the ventilator support removal. The opposite occurred in the capacitive reactance, both corporal and thoracic. So, the evaluation through the corporal bioimpedance in this work got statistically significant results, and it can be used as a method of evaluation improving the clinical diagnosis of the patient. / O objetivo deste trabalho é propor um novo método de avaliação através da bioimpedância corporal e torácica em recém-nascidos pré-termo com Síndrome do Desconforto Respiratório, submetidos ou não á ventilação mecânica invasiva. Foram avaliados trinta neonatos pré-termos com Síndrome do Desconforto Respiratório, internados na unidade de Terapia Intensiva Neonatal (UTIN) do Hospital Universitário Evangélico de Curitiba (HUEC), no período de agosto à novembro de 2004. A média da idade gestacional de ambos os grupos foi de 32 semanas e o peso de 1250g. Os recém-nascidos (RN) foram divididos em dois grupos, grupo A (15 neonatos), Síndrome do Desconforto Respiratório de média a moderada repercussão clínica, necessitando de suporte ventilatório invasivo. Grupo B (15 neonatos) Grau leve de Desconforto Respiratório, sem necessidade de suporte ventilatório. Os neonatos dos dois grupos foram avaliados conforme o boletim de Silverman-Andersen, a média percentual no grupo A foi de 77 e no grupo B de 3. Na análise estatística foram analisados cinco momentos do grupo A e comparado esses momentos com uma única observação do grupo B. Nos primeira mensuração realizada no grupo A, observa-se uma resistência tanto corporal (410 Ω) e torácica (32,53 Ω), baixa em relação a obtida no grupo B, onde a média percentual foi de 596 Ω, na resistência corporal e na torácica de 46,13 Ω. Na reatância capacitiva observa-se na primeira análise um comportamento inversamente proporcional, ocorrendo um aumento na reatância capacitiva tanto corporal como torácica no grupo A em relação ao grupo B. A medida que o neonato do grupo A, melhora clinicamente observa-se uma tendência ao aumento de valores de resistência tanto corporal com a torácica, correlacionada com a retirada da prótese ventilatório. Ocorrendo o inverso com a reatância capacitiva tanto corporal como torácica. Portanto, a avaliação através da bioimpedância corporal neste trabalho obteve resultados estatisticamente significativos podendo ser utilizada como um método de avaliação, enriquecendo o diagnóstico clínico do paciente.

No description available.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Thesis (MSc (Radiography))--Cape Peninsula University of Technology, 2017. / Background: Metabolic syndrome (MetS) is a clustering of cardiovascular disease (CVD) risk factors which include abdominal obesity, hyperglycaemia, hyper-triglyceridaemia, low HDL-cholesterol and hypertension. This cluster of metabolic deviations is believed to be the primary driver of the double global epidemic of diabetes (DM) and CVD, conditions which account for much of the social and economic global burden of disease. Similar to the global trend, a high prevalence of MetS (62%) and type 2 Diabetes Mellitus (T2DM) (28.2%) has been reported for the South African mixed ancestry population, with CVD risk significantly higher in subjects with DM. The increase in MetS prevalence is driven by the obesity epidemic and anthropometric cut-off values to define MetS for this particular component of the disease has been reported to differ widely between different populations and ethnicities. Currently the waist circumference (WC) cut-off value for MetS diagnosis needs to be determined and validated per ethnic group as opposed to the previously used European derived cut-off values (Alberti et al., 2006; 2009). Validation of the WC cut-off value needs to be against one of the so called gold standards of central obesity measurement, such as Computer Tomography (CT). This technique can measure subcutaneous fat (SAT) and visceral fat (VAT) individually, which is important because VAT has been reported to be associated with MetS and CVD. The current study forms part of a large research group, investigating the prevalence and risk factors for MetS and T2DM in the South African mixed ancestry population.

Purpose: The purpose of this study was to determine how differences in hydration states and ion content of hydrating fluids affected bioelectrical impedance (BI) and hydrostatic weighing (HW) measurements. Methods: Fifteen athletic subjects aged 19-56 yr were recruited. Relative body fat (%), fat- weight (FW), and fat-free weight (FW) were assessed using BI and HW under normal conditions (N), hypohydration (HPO), rehydration (RHY), and superhydration (SHY) states. During the RHY and SHY trial periods, subjects were hydrated with either distilled water or an electrolyte solution (ELS). HPO and SHY levels were set at 3% of each person's normally hydrated body weight. Results: Comparison between the distilled water and the ELS trials indicated that hydration solution had no effect on BI or HW. Thus, the results presented are the trial means of both hydration solutions combined. Both BI and HW were shown to be highly test-retest reliable (r-values: 0.96 and 0.99, respectively). The effects of exercise induced HPO followed by RHY on body composition values indicated that HW was very stable across measurement periods while BI was not. From N to the HPO state, BI %BF declined from 14.4 ± 5.3% to 12.3 ± 5.3%, respectively. After RHY, BIA %BF increased to 15.5 ± 5.8%. Similar findings occurred when subjects were superhydrated (N-BI = 13.2 ± 5.3%; SHY-BI = 15.4 ± 5.6%). With a comparison of the intercepts and slopes of HW and BIA for the N and SHY states, it was clear hydration status significantly affected the intercepts (HW: 0.37 vs. BI: 1.85) and not the slopes (HW: 1.00 vs BI: 0.99). As a result, a majority of all fluid changes were interpreted as FW by BI. During HPO, 82% of the weight loss was considered FW while during RHY or SHY, 128% and 85% of the water weight regain/gain was considered FW. Conclusion: These results indicate that BI is not a valid technique in athletes, especially when wanting to determine body composition effects of training/detraining. This study indicates that even small fluid changes such as those that occur with endurance training may be interpreted incorrectly as changes in an athlete's body fat content.

This study's purpose was to determine the validity of near-infrared interactance (NIR) and bioelectric impedance (BIA) in tracking changes in body composition over 12 wk of either a high intensity endurance (ET) or resistance (RT) training program in nondieting weight-stable untrained males. Prior to and following the control or training period, each subject completed a series of body composition analyses including hydrostatic weighing (HW) with a measurement of residual volume; anthropometric measurements including height, weight, skinfold, and girth; BIA measurement; and NIR measurements. Based on the HW results, there were no significant body composition changes in the control group. For the ET group, a significant decline in relative body fat resulted from a reduction in fat weight (FW) with no change in fat-free weight (FFW). In the RT group, both a significant decline in FW and an increase in FFW contributed to this group's decline in relative body fat. Tracking changes in relative body fat, FW, and FFW, skinfolds agreed reasonably well with HW in all groups while BIA and NIR did not always track body composition changes well. For example, SF and BIA were significantly correlated with the changes in FFW (HW = + 4.1%, SF = + 4.5%, BIA = + 3.1% NIR = - 0.7%) observed in the RT group compared to HW (SF: r-value = 0.45, SEE = 2.5; BIA; r = 0.33, SEE = 3.4) while the NIR measurements were nonsignificant (r = 0.09, SEE = 5.0). Interestingly, NIR underestimated the gain in FFW in the resistance trained group while BIA underestimated the changes in relative body fat, FW, and FFW in the endurance trained group. Based on these results, BIA aim NIR appear not to be appropriate measurement tools for tracking body composition changes in endurance and resistance training individuals respectively.

Background: In recent years several state high school athletic association have investigated methods to ensure the health and safety of high school wrestlers. One method implemented by the National Collegiate Athletic Association requires the prediction of minimum weight (MW) prior to the competition season. This weight certification program requires the assessment of body composition and hydration status. Results from those assessments place wrestlers in their lowest allowable wrestling weight class. There are a variety of measurement devises that have proven to be effective in measuring body composition. However, several considerations must be taken into account when choosing a devise such as affordability and reliability. Of those devices leg-to-leg bioelectrical impedance analysis (BIA) has been suggested for use with wrestlers. Purpose: To test the validity of bioelectrical impedance as an instrument of body composition and minimum wrestling weight compared to three-site skinfold using the Lohman-Brozek formula and the Bod Pod®; among hydrated high school wrestlers. Methods: Criterion for this study was the Bod Pod®. Subjects included 98 high school wrestlers taking part in the pre-season wrestling weight certification program implemented by the Virginia High School League. Hydration was assessed and a urine specific gravity (USG) ≤ 1.020 was assigned as the level of hydration. Results: In order to investigate the validity of BIA in this study a repeated measure ANOVA with between-subjects factors was used to assess the equality of means between the three measurement devices. Also, in order to investigate hydration affect subjects were divided into two categories (hydrated and dehydrated). Finally, prior to analysis subjects were placed in weight categories based on their assigned wrestling weight class. Results of this study demonstrated that the three measurement devices did not produce similar results and it was concluded that hydration level had no affect on the measurements. Therefore, at this time BIA should not be considered as an alternative method for assessing body composition in high school wrestling weight certification programs. / Ph. D.