Muscle Oxygen Extraction during Vascular Occlusion Test in Physically Very Active versus Inactive Healthy Men: A Comparative Study.

An increase in the delivery and use of oxygen to the musculature in physically active subjects are determinants of improving health-related aerobic capacity. Additional health benefits, such as an increase in the muscle mass and a decrease in fat mass, principally in the legs, could be achieved with weekly global physical activity levels of more than 300 min. The objective was to compare the muscle vascular and metabolic profiles of physically very active and inactive subjects. Twenty healthy men participated in the study; ten were assigned to the physically very active group (25.5 ± 4.2 years; 72.7 ± 8.1 kg; 173.7 ± 7.6 cm) and ten to the physically inactive group (30.0 ± 7.4 years; 74.9 ± 11.8 kg; 173.0 ± 6.4 cm). The level of physical activity was determined by the Global Physical Activity Questionnaire (GPAQ). A resting vascular occlusion test (5 min of an ischemic phase and 3 min of a reperfusion phase) was used, whereas a near-field infrared spectroscopy (NIRS) device was used to evaluate the muscle oxygenation in the right vastus lateralis of the quadriceps muscle. The area under the curve of the deoxyhemoglobin (HHb) during the ischemic phase and above the curve of the tissue saturation index (TSI) during the reperfusion phase were obtained to determine muscle metabolic and vascular responses, respectively. Physically very active group showed a higher absolute HHb (3331.9 ± 995.7 vs. 6182.7 ± 1632.5 mmol/s) and lower TSI (7615.0 ± 1111.9 vs. 5420.0 ± 781.4 %/s) and relative to body weight (46.3 ± 14.6 vs. 84.4 ± 27.1 mmol/s/kg and 106.0 ± 20.6 vs. 73.6 ± 13.8 %/s/kg, respectively), muscle mass (369.9 ± 122.2 vs. 707.5 ± 225.8 mmol/kg and 829.7 ± 163.4 vs. 611.9 ± 154.2 %/s/kg) and fat mass (1760.8 ± 522.9 vs. 2981.0 ± 1239.9 mmol/s/kg and 4160.0 ± 1257.3 vs. ±2638.4 ± 994.3 %/s/kg, respectively) than physically inactive subjects. A negative correlation was observed between HHb levels and TSI (r = -0.6; p < 0.05). Physically very active men (>300 min/week) present better muscle oxidative metabolism and perfusion and perform significantly more physical activity than physically inactive subjects. Extra benefits for vascular health and muscle oxidative metabolism are achieved when a subject becomes physically very active, as recommended by the World Health Organization. In addition, a higher level of physical activity determined by GPAQ is related to better vascular function and oxidative metabolism of the main locomotor musculature, i.e., the quadriceps.

Relación entre la Temperatura de Superficie, la Composición Corporal e Indicadores Antropométricos de Obesidad y Sobrepeso / Relationship Between Surface Temperature, Body Composition and Anthropometric Indicators of Obesity and Overweight

La termografía por infrarrojo (TI) permite evaluar la temperatura corporal, medir los cambios en la disipación del calor corporal en superficie y relacionarlos con las características de composición corporal e índices antropométricos. Aumentar el número de registros de zonas corporales evaluadas con TI y establecer las relaciones de estas temperaturas (32 áreas corporales) con variables de composición corporal e índices antropométricos, como el índice de masa corporal (IMC), índice cintura cadera, índice cintura estatura, en hombres adultos divididos según su estado ponderal. Participaron 60 hombres, adultos sanos, divididos en 2 grupos: grupo 1 (n=30), con IMC ≤ 24,9, edad 23,2 ± 3,9 años, masa corporal 66,5 ± 6,5 kg, y talla 170,5 ± 7,4 cm; y, grupo 2 (n= 30), con IMC > 24,9, edad 29,4 ± 9,9 años, masa corporal 84,5 ± 11,9 kg, y talla 172,0 ± 7,18 cm. Se realizaron evaluaciones antropométricas y de TI. Sujetos con IMC ≤ 24,9 kg/ m2 presentaron valores mayores de temperatura superficial, en todas las zonas estudiadas, a diferencia de los sujetos con niveles de IMC > 24,9 kg/m2, donde la disipación del calor corporal fue menor. Existe una estrecha relación entre la temperatura superficial de la piel y el IMC, donde sujetos con un IMC normal mostraron una disipación de calor y valores de temperatura superficial mayores, en todas las zonas evaluadas, a diferencia de los sujetos con un IMC que se encontraba por encima del límite de normalidad.

SUMMARY: Infrared thermography (IT) makes it possible to assess body temperature, measure changes in body heat dissipation on the surface, and relate them to body composition characteristics and anthropometric indices. The objective of this study was to increase the number of records of body areas evaluated with IT and establish the relationships of these temperatures (32 body areas) with body composition variables and anthropometric indices, such as body mass index (BMI), waist-hip ratio, waist-height ratio, in adult men divided according to their weight status. A total of 60 healthy adult men participated, divided into 2 groups: group 1 (n=30), with a body mass index (BMI) ≤ 24.9, age 23.2 ± 3.9 years, body mass 66.5 ± 6.5 kg, and height 170.5 ± 7.4 cm; and, group 2 (n = 30), with BMI > 24.9, age 29.4 ± 9.9 years, body mass 84.5 ± 11.9 kg, and height 172.0 ± 7.18 cm. Anthropometric and IT assessments were performed. Subjects with BMI ≤ 24.9 kg/ m2 presented higher values of surface temperature in all areas studied, unlike subjects with BMI levels > 24.9 kg/m2, where body heat dissipation was lower. There is a close relationship between skin surface temperature and BMI, where subjects with a normal BMI showed higher heat dissipation and surface temperature values, in all evaluated areas, unlike subjects with a BMI that was above the normal limit.

Association between Fractional Oxygen Extraction from Resting Quadriceps Muscle and Body Composition in Healthy Men.

This study aimed to associate body composition with fractional oxygen extraction at rest in healthy adult men. Fourteen healthy adults (26.93 ± 2.49 years) from Chile participated. Body composition was assessed with octopole bioimpedance, and resting muscle oxygenation was evaluated in the vastus lateralis quadriceps with near-infrared spectroscopy (NIRS) during a vascular occlusion test, analyzing the muscleVO2, resaturation velocity during reactive hyperemia via the muscle saturation index (%TSI), and the area above the curve of HHb (AACrep). It was observed that the total and segmented fat mass are associated with lower reoxygenation velocities during hyperemia (p = 0.008; ß = 0.678: p = 0.002; ß = 0.751), and that the total and segmented skeletal muscle mass are associated with higher reoxygenation velocities during hyperemia (p = 0.020; ß = -0.614: p = 0.027; ß = -0.587). It was also observed that the total and segmented fat mass were associated with a higher area above the curve of HHb (AACrep) during hyperemia (p = 0.007; ß = 0.692: p = 0.037; ß = 0.564), and that total and segmented skeletal muscle mass was associated with a lower area above the curve of HHb (AACrep) during hyperemia (p = 0.007; ß = -0.703: p = 0.017; ß = -0.632). We concluded that fat mass is associated with lower resaturation rates and lower resting fractional O2 extraction levels. In contrast, skeletal muscle mass is associated with higher resaturation rates and fractional O2 extraction during reactive hyperemia. The AACrep may be relevant in the evaluation of vascular adaptations to exercise and metabolic health.

Relación entre la Composición Corporal, Condición Física y Capacidad Operativa en Militares Chilenos / Relationship Between Body Composition, Physical Condition and Operational Capacity in Chilean Military

La composición corporal engloba una serie de variables relacionadas con la salud e influye en la condición física. A pesar de ello, existe poca evidencia sobre sus efectos en la capacidad operativa en militares. El objetivo de este estudio fue relacionar la composición corporal, la condición física y la capacidad operativa de militares chilenos. Participaron 57 militares chilenos (26,9 ± 4,8 años), con especialización operativa en infantería. La composición corporal fue evaluada con bioimpedancia octopolar estimando masa libre de grasa, tejido muscular y tejido adiposo, entre otras variables. También se realizaron las siguientes pruebas de condición física: 5000 m planos, dominadas, abdominales y flexibilidad, así como cuatro pruebas específicas de actividades operativas militares específicas (situación de combate simulado). Los resultados mostraron un porcentaje de tejido muscular de 45,4 ± 2,9 % (IC95%: 44,6 - 46,2), mientras que el porcentaje de tejido adiposo fue de 20,3 ± 4,9 % (IC95%: 14,7 - 17,3). Se encontraron correlaciones negativas de pequeña magnitud entre el tiempo de carrera (5000 m) y el tejido muscular (%) (r = -0,275) y positiva con el tejido adiposo (%) (r = 0,294). Sin embargo, se observaron correlaciones de alta magnitud entre dominadas y tejido muscular (%) (r = 0,517) y tejido adiposo (%) (r = -0,558). El tejido adiposo se relacionó negativamente con la capacidad aeróbica, fuerza de brazos(??) y fuerza resistencia abdominal, mientras que el tejido muscular se relacionó positivamente con estas mismas variables. No se apreciaron correlaciones entre la composición corporal y la capacidad operativa militar (p<0,05). Se concluye que la composición corporal y la condición física no se relacionan con la capacidad operativa militar en situación de combate en especialistas en infantería, pero si la composición corporal se relaciona con la fuerza y la capacidad cardiorrespiratoria.

SUMMARY: Body composition encompasses a series of variables that are health-related and influence physical condition. Nevertheless, there is little evidence on its effects on the operational capacity of the military. The objective of this study was to relate the body composition, the physical condition and the operational capacity of the Chilean military. Fifty-seven Chilean soldiers (26.9 ± 4.8 years) participated, with operational specialization in infantry. Body composition was evaluated with octopolar bioimpedance, estimating fat- free mass, muscle tissue, and adipose tissue, among other variables. The following physical condition tests were also carried out: 5000 m flat, pull-ups, abdominals and flexibility, as well as four specific tests of specific military operational activities (simulated combat situation). The results showed a percentage of muscle tissue of 45.4 ± 2.9 % (95%CI: 44.6 - 46.2), while the percentage of adipose tissue was 20.3 ± 4.9 % (95%CI). : 14.7-17.3). Negative correlations of small magnitude were found between race time (5000 m) and muscle tissue (%) (r = -0.275) and positive with adipose tissue (%) (r = 0.294). However, high magnitude correlations were observed between pull-ups and muscle tissue (%) (r = 0.517) and adipose tissue (%) (r = -0.558). Adipose tissue was negatively related to aerobic capacity, arm strength, and abdominal endurance strength, while muscle tissue was positively related to these same variables. No correlations were found between body composition and military operational capacity (p<0.05). It is concluded that body composition and physical condition are not related to military operational capacity in combat situations in infantry specialists, but body composition is related to strength and cardiorespiratory capacity.

Características antropométricas, capacidad de salto vertical y resistencia de carrera de bomberos, en servicio activo, con relación a la edad / Anthropometric characteristics, vertical jumping capacity and running endurance, in active-duty firefighters, in relation to age

El objetivo de este estudio fue establecer relaciones entre las variables de rendimiento físico e índices antropométricos según la edad de bomberos adultos chilenos, en servicio activo, provenientes de la región de Valparaíso. Participaron 68 bomberos, hombres, sanos, en servicio activo, que fueron divididos en dos grupos según edad; 30 años (n = 32; 40,6 ± 8,5 años). Se evaluaron las variables antropométricas de masa corporal (MC), estatura, perímetro de cintura (PC), índice de masa corporal (IMC] = Peso /estatura2 [m]) e índice cintura-estatura (ICE). La capacidad de salto vertical fue evaluada con los protocolos de Squat Jump, Countermovement Jump y Abalakov Jump. La resistencia en carrera fue estimada con la prueba de Course Navette y se calculó indirectamente el consumo de oxígeno (VO2). Las variables antropométricas para el grupo > 30 años fueron mayores en comparación al grupo de menor edad en MC (p = 0.027), IMC (p = 0.015), PC (p 0.05) entre ambos grupos. Existió una correlación significativa positiva entre la edad y las variables de MC (r = 0,252), IMC (r = 0,307), ICE (r = 0,431) y PC (r= 0,401). Al comparar ambos grupos de edad hubo diferencias antropométricas, pero no en la condición física. Se sugiere reforzar programas de entrenamiento para optimizar la composición corporal y capacidad física de bomberos en servicio activo para responder a las exigentes tareas que demanda este ámbito laboral.

SUMMARY: The aim of this study was 1) to compare anthropometric characteristics, jumping ability, and running endurance according to age and 2) to determine the relationship between age and physical performance parameters in Chilean adult firefighters in active service from the Valparaíso region. Sixty-eight healthy male firefighters, in active service, were divided into two groups according to age; 30 years (n = 32; 40.6 ± 8.5 years) participated. The anthropometric variables of body mass (BM), height, waist circumference (WC), body mass index (BMI = weight/height2 [m]) and waist-to-height ratio (WHR) were evaluated. Vertical jumping ability was assessed with the Squat Jump, Countermovement Jump and Abalakov Jump protocols. Running endurance was estimated with the Course Navette test and oxygen consumption (VO2) was calculated indirectly. Anthropometric variables for the > 30 years group were higher compared to the younger age group in BM (p = 0.027), BMI (p = 0.015), WC (p 0.05). There was a significant positive correlation between age and the variables of BM (r = 0.252), BMI (r = 0.307), WHR (r = 0.431) y WC (r= 0.401). When comparing both age groups, there were anthropometric differences, but not in physical condition. It is suggested to reinforce training programs to optimize the body composition and physical capacity of firefighters in active service in order to respond to the demanding tasks demanded by this work environment.

Effects of Inspiratory Muscle Training on Muscle Oxygenation during Vascular Occlusion Testing in Trained Healthy Adult Males.

Inspiratory muscle training (IMT) may have an additional effect on cardiovascular autonomic modulation, which could improve the metabolism and vascular function of the muscles. AIM: To determine the effects of IMT on vascular and metabolic muscle changes and their relationship to changes in physical performance. METHODS: Physically active men were randomly placed into an experimental (IMTG; n = 8) or IMT placebo group (IMTPG; n = 6). For IMT, resistance load was set at 50% and 15% of the maximum dynamic inspiratory strength (S-Index), respectively. Only the IMTG's weekly load was increased by 5%. In addition, both groups carried out the same concurrent training. Besides the S-Index, a 1.5-mile running test, spirometry, and deoxyhemoglobin (HHbAUC during occlusion) and reperfusion tissue saturation index (TSIMB and TSIMP: time from minimum to baseline and to peak, respectively) in a vascular occlusion test were measured before and after the 4-week training program. In addition, resting heart rate and blood pressure were registered. RESULTS: IMTG improved compared to IMTPG in the S-Index (Δ = 28.23 ± 26.6 cmH2O), maximal inspiratory flow (MIF: Δ = 0.91 ± 0.6 L/s), maximum oxygen uptake (Δ = 4.48 ± 1.1 mL/kg/min), 1.5-mile run time (Δ = -0.81 ± 0.2 s), TSIMB (Δ = -3.38 ± 3.1 s) and TSIMP (Δ = -5.88 ± 3.7 s) with p < 0.05. ΔVO2max correlated with S-Index (r = 0.619) and MIF (r = 0.583) with p < 0.05. Both ΔTSIMB and TSIMP correlated with ΔHHbAUC (r = 0.516 and 0.596, respectively) and with Δ1.5-mile run time (r = 0.669 and 0.686, respectively) with p < 0.05. CONCLUSION: IMT improves vascular function, which is related to additional improvements in physical performance.

Near-Infrared Spectroscopy Used to Assess Physiological Muscle Adaptations in Exercise Clinical Trials: A Systematic Review.

Using muscle oxygenation to evaluate the therapeutic effects of physical exercise in pathologies through near-infrared spectroscopy (NIRS) is of great interest. The aim of this review was to highlight the use of muscle oxygenation in exercise interventions in clinical trials and to present the technological characteristics related to the equipment used in these studies. PubMed, WOS, and Scopus databases were reviewed up to December 2021. Scientific articles that evaluated muscle oxygenation after exercise interventions in the sick adult population were selected. The PEDro scale was used to analyze the risk of bias (internal validity). The results were presented grouped in tables considering the risk of bias scores, characteristics of the devices, and the effects of exercise on muscle oxygenation. All the stages were carried out using preferred reporting items for systematic reviews and meta-analyses (PRISMA). The search strategy yielded 820 clinical studies, of which 18 met the eligibility criteria. This review detailed the characteristics of 11 NIRS devices used in clinical trials that used physical exercise as an intervention. The use of this technology made it possible to observe changes in muscle oxygenation/deoxygenation parameters such as tissue saturation, oxyhemoglobin, total hemoglobin, and deoxyhemoglobin in clinical trials of patients with chronic disease. It was concluded that NIRS is a non-invasive method that can be used in clinical studies to detect the effects of physical exercise training on muscle oxygenation, hemodynamics, and metabolism. It will be necessary to unify criteria such as the measurement site, frequency, wavelength, and variables for analysis. This will make it possible to compare different models of exercise/training in terms of time, intensity, frequency, and type to obtain more precise conclusions about their benefits for patients.

Comparison of the Agonist/Antagonist Tensional Balance of the Knee between Two Isokinetic Positions: A Pilot Study on a Sample of High-Level Competitive Soccer Players.

Isokinetic knee dynamometry evolves towards more precise techniques, such as the calculation of the functional ratio. This study evaluated the influence of an intermediate hip position called the unified reclined position (URP) compared to the classic sitting position, (CSP) on hamstring eccentric PT values (Hexc30) and conventional (Hcon60/Qcon60) and functional (Hexc30/Qcon60) ratios. Twenty Spanish high-level competitive soccer players (20.4 ± 4.44 years) were evaluated in CSP and in URP. The hip angle in URP (44°) was determined with a passive extensibility test (quadriceps and hamstrings), looking for an agonist/antagonist tension balance. The following were performed: three repetitions (60°/s) and five repetitions (240°/s) in concentric quadriceps and hamstrings mode; and three repetitions (30°/s) in concentric and eccentric for the hamstrings. At 30°/s, the CSP presents higher values of maximal eccentric hamstring strength than URP, (Dom + N-Dom leg (Nm): CSP = 148.3 ± 19.5 vs. URP 143.5 ± 23.2); p = 0.086 (n.s.). The conventional relationship did not show data justifying the preference for URP over CSP (p = 0.86 (n.s.)). However, although the functional index did not show significant values (p = 0.97 (n.s.), it did show a greater number of subjects with imbalances measured in URP (five in URP vs. two in CSP). An assessment angle of the hip closer to sports reality seems to favor the use of the URP as a complementary method to the CSP. These data stimulate new studies using URP together with the classic protocol.

Asociación entre la termografía por infrarrojo y parámetros antropométricos de riesgo cardiometabólico en hombres / Association between infrared thermography, anthropometry and cardiovascular risk parameters in men

RESUMEN: Los parámetros antropométricos para la estimación de la composición corporal son variables comúnmente utilizadas en la identificación de factores de riesgo cardiovascular (FRCV). En este sentido la termografía por infrarrojo (TI) podría ser utilizada como una herramienta que aporte información relevante en la evaluación de los FRCV mediante la estimación de la temperatura superficial en la piel y su relación con medidas antropométricas asociadas a estos factores. El objetivo de este estudio fue determinar la relación de la temperatura superficial de hombres adultos con variables antropométricas asociadas a FRCV. Participaron 64 hombres sanos de 26,4 ± 7,8 años, 76,1 ± 13,3 kg de masa corporal, 171,3 ± 7,2 cm de estatura y 25,9 ± 3,7 kg/m2 de índice de masa corporal (IMC). Se realizaron evaluaciones antropométricas de 6 pliegues cutáneos (tricipital, subescapular, supra-espinal, abdominal, muslo medio y pantorrilla), circunferencia de cintura y cadera, además de mediciones de la temperatura superficial mediante TI en las zonas de medición. Se encontraron relaciones significativas negativas entre la temperatura superficial y las mediciones de los pliegues cutáneos a nivel subescapular, supra-espinal, muslo y pantorrilla (p < 0,01; r = -0,39 a -0,55). La temperatura promedio de la TI de los 6-pliegues, y todas las TI individuales de los pliegues presentaron correlaciones negativas significativas con el IMC, perímetro de cintura, índice cintura cadera, índice cintura estatura y la sumatoria de 6 pliegues cutáneos (p < 0,05; r = -0,35 a -0,65). Se puede concluir que existe una relación entre la temperatura superficial de la piel y algunos parámetros antropométricos de la composición corporal que muestran estar asociados a FRCV, pudiendo ser la TI una herramienta útil para complementar la evaluación de estos parámetros.

SUMMARY: Anthropometric parameters for the estimation of body composition are variables commonly used in the identification of cardiovascular risk factors (CVRFs). In this regard, infrared thermography (IT) could be used as a tool that provides relevant information in the CVRFs assessment by estimating skin surface temperature and its relationship with the anthropometric measures associated with these factors. The aim of this study was to determine the relationship of skin surface temperature in adult men with anthropometric variables associated with CVRFs. The study gathered sixty-four healthy men aged 26.4 ± 7.8 years, 76.1 ± 13.3 kg body mass, 171.3 ± 7.2 cm height and 25.9 ± 3.7 kg/m2 body mass index (BMI). Anthropometric assessments of 6 skinfolds (tricipital, subscapular, suprascapular, supraspinal, abdominal, mid-thigh, and calf), waist and hip circumference were conducted, as well as IT surface temperature measurements at the measurement areas. Significant negative relationships were found between surface temperature and skinfold measurements at the subscapular, supraspinal, thigh and calf levels (p < 0.01; r = -0.39 to -0.55). The average IT temperature of the 6- folds and all individual folds IT had significant negative correlations with BMI, waist circumference, waist hip ratio, waist height ratio, and the sum of 6 skinfolds (p < 0.05; r = -0.35 to -0.65). There is a relationship between skin surface temperature and some body composition anthropometric parameters that indicate and association with CVRFs, therefore, IT may be a useful tool to complement the assessment of these parameters.

Perfil de composición corporal en militares élite chilenos / Body composition profile of elite Chilean military

RESUMEN: La Bioimpedancia Eléctrica (BIA), al ser una técnica no invasiva pero de elevada precisión, se ha convertido en la actualidad en una herramienta valiosa para determinar la composición corporal en militares, facilitado el control de las distintas variables que se asocian a cada especialidad. El objetivo del presente estudio fue describir el perfil de composición corporal en militares de elite al momento de finalizar un curso de especialización. Participaron 11 militares con un rango de edad entre 22 y 29 años. Se evalúo la composición corporal a través de BIA, inmediatamente después de finalizado un curso de especialización para militares de élite. Las evaluaciones en los militares sobre las variables de la composición corporal a través de BIA mostraron: peso corporal de 84,3 ± 4,52 kg, talla 1,78 ± 0,06 m, índice de masa corporal (IMC) 26,5 ± 1,09, tejido adiposo de 13,7 ± 3,65 %, tejido muscular 49,5 ± 2,34 %, masa libre de grasa 72,7 ± 5,23 kg y 53,2 ± 3,78 l de agua corporal total. Conclusiones: Los militares de elite presentaron elevados niveles de masa libre de grasa, tejido muscular y bajos niveles de tejido adiposo lo que favorece el desarrollo de las actividades militares especializadas y disminuye el riesgo de lesiones. Los datos aquí recogidos sirven como marco de referencia para futuros estudios.

SUMMARY: Electrical bioimpedance (BIA), being a non- invasive technique but with high precision, has become a valuable tool for determining body composition in the military, facilitating the control of the different variables associated with each specialty. The aim of the present study was to describe the body composition profile of elite military personnel at the end of a specialization course. Eleven military personnel between 22 and 29 years of age participated in the study. Body composition was assessed by BIA immediately after completion of a specialization course for elite military personnel. Assessments in the military on body composition variables through BIA showed: body weight of 84.3 ± 4.52 kg, height 1.78 ± 0.06 m, body mass index (BMI) 26.5 ± 1.09, adipose tissue of 13.7 ± 3.65 %, muscle tissue 49.5 ± 2.34 %, fat free mass 72.7 ± 5.23 kg and 53.2 ± 3.78 l of total body water. Conclusions: Elite military personnel presented high levels of fat free mass, muscle tissue and low levels of adipose tissue which favors the development of specialized military activities and decreases the risk of injury. The data collected here serve as a frame of reference for future studies.

Características de composición corporal, ángulo de fase y agua corporal en paracaidistas chilenos de elite / Characteristics of body composition, phase angle and body water in elite Chilean skydivers

RESUMEN: Durante la práctica del paracaidismo, una deficiente composición corporal no sólo puede afectar el rendimiento deportivo, sino que, además, incrementa la probabilidad de sufrir una lesión o accidente grave. Conocer las características de sus componentes, podría ayudar a prevenirlas. El objetivo del estudio fue describir la composición corporal, ángulos de fase y agua corporal total en paracaidistas chilenos de alta competencia. Participaron del estudio 8 paracaidistas profesionales del Team Chile® (33,4 ± 4,9 años) con más de seis años de experiencia. La evaluación de las masas grasa, muscular, libre de grasa, magra y visceral, así como el ángulo de fase y el agua corporal total obtenida a través de impedancia bioeléctrica. Los deportistas presentaron un peso corporal de 76,7 ± 5,7 kg, estatura 1,72 ± 0,1 m e IMC 26,0 ± 1,9 kg/m2. La composición corporal promedio mostró un 20,6 ± 3,0 % de masa grasa, 44,9 ± 2,0 % de masa muscular y 79,4 ± 3,0 % de masa libre de grasa. El ángulo de fase promedio fue de 7,25 ± 0,33°. El agua corporal total de los participantes fue de 44,6 ± 3,2 1. Se concluye que los resultados obtenidos pueden ser utilizados por los profesionales de las ciencias del deporte como valores de referencia para el control de la composición corporal, fase angular y agua corporal en paracaidistas para optimizar el rendimiento deportivo y evitar lesiones.

SUMMARY: Unsuitable body composition in skydivers not only affect the sport performance but also could increase the probability of risk injury or severe accident; hence, to determine body composition characteristics could be helpful to prevent such events. This study aimed to describe body composition, phase angle, and total body water in highly trained Chilean skydivers. Eight Team Chile® professional skydivers (33.4 ± 4.9 years) with more than 6 years of experience participated in this study. Fat mass, muscle mass, fat-free mass, lean mass, visceral mass, phase angle, and total body water were measured by bioelectrical impedance. Skydivers had a bodyweight of 76.7±5.7 kg, a height of 1.72 ±0.1 m, and a body mass index of 26.0 ±1.9 kg/m2. Regarding body composition, they had a fat mass of 20.6 ±3.0 %, a muscle mass of 44.9 ±2.0 %, and a fat-free mass of 79.4 ±3.0 %. Phase angle and total body water were 7.25 ±0.3° and 344.6±3.2, respectively. The present findings could be useful to science sport professionals as reference values of body composition, phase angle, and total body water of highly trained skydivers to improve sports performance and avoid injuries.

Asociación entre la termografía por infrarrojo, parámetros antropométricos y gasto energético de reposo en hombres / Association between infrared thermography, anthropometry parameters and rest energy expenditure in men

RESUMEN: Es reconocido que un incremento de la grasa corporal subcutánea es capaz de alterar el patrón de liberación de calor a través de la piel. Sin embargo, la asociación con otras variables antropométricas y la influencia del gasto energético en reposo (GER), han sido escasamente abordadas. Este estudio determinó la relación de la temperatura de la piel con variables antropométricas, peso corporal y GER de hombres adultos sanos. Participaron en el estudio un total de 24 varones sanos de 33,9±8,7 años de edad, 85,8±9,7 kg de peso corporal, 172,5±6,1 cm de estatura y 28,9±3,4 kg/m2 de índice de masa corporal (IMC). Se realizaron evaluaciones antropométricas, de termografía por infrarrojo y del GER por calorimetría indirecta, con analizador de gases. La temperatura promedio de los 6-pliegues, y las individuales (toracoabdominales, supra-espinal y abdominal), tuvieron correlaciones negativas con el IMC, perímetro de cintura, índice cintura cadera, índice cintura estatura, y la sumatoria de 6 pliegues; todos con p<0,05. Además, la temperatura del pliegue supraespinal tuvo una correlación negativa con el porcentaje de masa adiposa (MA%), r=0,47(p=0,0194). La MA% y el IMC tuvieron correlaciones negativas con el GER, con r=-0,59 (p=0,002) y r=-0,53 (p=0,006), respectivamente. El promedio de temperatura de los 6-pliegues presentó una correlación positiva con el GER (r=0,44; p=0,02). La composición corporal causa una modificación en los patrones de termografía superficial local, sin afectar la relación entre el promedio de la temperatura superficial total con el GER, pudiendo éste ser un factor predictor.

SUMMARY: It is known that an increase in the subcutaneous body fat can alter the pattern of heat release through the skin. However, the relationship with other anthropometric variables and the influence of the Resting Energy Expenditure (REE) have scarcely been addressed. To determine the relationship of skin temperature with different anthropometric variables, body weight, and the REE of healthy adult males. The participants were a total of 24 healthy males of 33.9±8.7 years-old, 85.8±9.7 kg of body mass, 172.5±6.1 cm of height, and 28.9±3.4 kg/m2 of body mass index (BMI). Anthropometric, infrared thermography, and indirect calorimetry REE assessments were performed with gas analyzer. The six skinfolds average temperature, as well as the individual skinfolds (thoracoabdominal, supraspinal, and abdominal), had negative correlations with the BMI, waist circumference, waist- hip ratio, waist-to-height ratio, and the sum of the six skinfolds, all with p<0.05. In addition, the temperature of the supraspinal fold had a negative correlation with the percentage of fat mass (MA%), r=0.47 (p=0.0194). MA% and BMI had negative correlations with REE, with r=-0.59 (p=0.002) and r=-0.53 (p=0.006), respectively. The six-skinfolds average temperature presented a positive correlation with the REE (r=0.44; p=0.02). Body composition changes cause a modification in the local surface thermography patterns without affecting the relationship between the average total body surface temperature with the REE; therefore, this could act as a predictive factor.

Cambios morfoestructurales en soldados conscriptos después de cuatro semanas de entrenamiento físico básico / Morpho-structural changes in conscript soldiers after four weeks of basic physical training

Introducción: El entrenamiento físico en la formación militar tiene por objetivo desarrollar la preparación física y psicológica frente a condiciones ambientales adversas. Objetivo: Determinar los cambios en la composición corporal y el somatotipo, producto del periodo de entrenamiento físico básico, en la formación militar de cuatro semanas de duración en soldados conscriptos. Método: Se evaluaron 28 varones (edad: 18,9 ± 0,9 años; estatura: 1,75 ± 0,1 m; masa corporal: 67 ± 8,7 kg; índice de masa corporal: 22,5 ± 2,4 y 70,88 ± 26,57 de ∑6 pliegues) que ingresaron al periodo de formación militar en la Fuerza Aérea de Chile, Base Quintero. Se entregó un consentimiento informado previo a la realización del estudio y se siguieron las indicaciones establecidas en la declaraciónn de Helsinki. Los participantes fueron sometidos a un plan de entrenamiento físico con una duración de 4 semanas, en las instalaciones del centro militar. Resultados: Con posterioridad al entrenamiento físico, hubo una disminución significativa de la masa adiposa (p < 0,01), con un aumento de la masa muscular (p < 0,01). No se observaron diferencias significativas en los componentes del somatotipo (Pre: 3,29 - 4,78 - 2,59 vs. Post: 2,73 - 4,72 - 2,73; p = 0,24). Conclusiones: Se concluye que el entrenamiento físico en militares, durante un periodo corto de cuatro semanas, provoca cambios rápidos y significativos en la composición corporal de los soldados; cambios que no alcanzaron a observarse en el somatotipo(AU)

Introduction: The objective of physical training in military training is to develop physical and psychological preparation in adverse environmental conditions. Objective: Determine the changes in body composition and somatotype product of basic physical training in military training for four weeks in conscript soldiers. Methods: 28 men were evaluated (age: 18.9 ± 0.9 years; height: 1.75 ± 0.1 m; weight: 67 ± 8.7 kg; BMI: 22.5 ± 2.4 and ∑6 folds 70.88 ± 26.57) who entered the period of military training in the Chilean Air Force, Quintero headquarters. Informed consent was given before the study; the indications established in the Declaration of Helsinki were followed. The participants were incorporated into a physical training plan for 4 weeks. The program was carried out in the facilities of a military center. Results: After physical training there was a significant decrease in adipose mass (p<0.01) and an increase in muscle mass (p<0.01). There were no significant differences in the somatotype components (Pre: 3.29-4.78-2.59 vs. Post: 2.73-4.72-2.73; p = 0.24). Conclusion: It is concluded that physical training in the military, during a short period of four weeks, causes rapid and significant changes in the body composition of the subjects that are not observed with such clarity through the somatotype(AU)

Inspiratory muscle training improves the swimming performance of competitive young male sprint swimmers.

BACKGROUND: Inspiratory muscle training (IMT) stimulates the strengthening of the respiratory muscles by placing a resistance to the entry of air into the lung. The objective was to observe the effect of IMT on swimming performance, and its relationship with inspiratory strength and lung function. METHODS: Fifteen male swimmers (age=15.1±1.1 years) were divided into an experimental group (EG; N.=9) and a sham control group (SCG; N.=6). Lung flows/volumes using spirometry, dynamic inspiratory strength (S-Index), maximum inspiratory flow (MIF), and swimming tests (50-m, 100-m and 200-m) were measured before and after a four-week aerobic swimming training program (R1-R2) and IMT. An initial load at 50% and 15% of S-Index was adjusted for EG and SCG respectively. Only the EG increased the initial load by 5% each week. RESULTS: The S-Index and MIF were only increased in the EG after IMT (∆S-Index=18.0±8.8 cmH2O and ∆MIF=0.7±0.33 L·min-1; P<0.05). The same occurred for FVC (∆=0.3±0.2 l), and MVV (∆=6.9±3.6 l·min-1) (P<0.05). For swimming performances, the EG swimming times decreased significantly respect to CG for 50-m (∆EG=-1.2±0.3 s vs. ∆CG=-0.1±0.2 s), 100-m (∆EG=-2.9±1 s vs. ∆CG=-0.7±0.5 s) and 200-m (∆EG=-7.3±2.8 s vs. ∆CG=-2.0±1 s) with P<0.05. Finally, the S-Index and MIF had a negative correlation with swimming performances for 50-m (S-Index, r=-0.72; MIF, r=-0.70) and 100-m (S-Index, r=-0.65; MIF, r=-0.62) with P<0.05. CONCLUSIONS: A short-period IMT increases the maximum S-Index, ventilation and MIF which positively influence the swimming performance of young swimmers.

El B-hidroxi-B-metilbutirato (HMB) como suplemento nutricional (I): metabolismo y toxicidad / B-Hidroxy-B-Methylbutyrate as a dietary supplement (I); metabolism and toxicity

Introducción: El β-hidroxi-β-metilbutirato (HMB) es un metabolito de la leucina producido a partir del ácido α-cetoisocaproico. El HMB se utiliza como suplemento nutricional en el deporte desde 1997, atribuyéndosele una disminución de la proteólisis muscular. En los últimos años, se han descrito efectos positivos del HMB en diversas patologías, lo cual aumenta su probable utilidad para la mejora de la salud. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se abordan el metabolismo y la posible toxicidad del HMB. Resultados: Diversos estudios relacionan al HMB con el metabolismo del colesterol en el músculo esquelético, probablemente reduciendo la proteólisis, a través del 3-hidroxi-3-metilglutaril-coenzima A, que se transforma a mevalonato, actuando como precursor en la síntesis de colesterol. Sin embargo, el HMB podría transformarse en beta-hidroxi-butirato a través del metabolismo del acetoacetato, por medio de la beta-hidroxibutirato dehidrogenasa. Por otra parte, la forma química más habitual en los suplementos nutricionales es la sal de calcio de HMB y la dosis más utilizada, de 3 g de HMB/día. Los estudios realizados en humanos y en animales muestran que no existen efectos adversos por el consumo de HMB. Conclusiones: Los efectos metabólicos y la ausencia de toxicidad del HMB lo hacen adecuado para su uso como suplemento nutricional (AU)

Introduction: β-hydroxy-β-methylbutyrate (HMB) is a leucine metabolite produced from α-ketoisocaproic acid. HMB supplementation has been used as a dietary supplement in sports since 1997, with the aim of decreasing muscle proteolysis. In recent years, positive effects have been reported in different pathologies, which suggests potential health benefits. Aims: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. Methods: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. Results were divided into two parts; this article presents the results about both HMB metabolism and possible toxicity. Results: Studies show that HMB is related to cholesterol metabolism in skeletal muscle, which could reduce proteolysis, through hydroxy-methyl-glutaryl-coenzyme A and mevalonate as a precursor in the synthesis of cholesterol. However, HMB could also be transformed from acetoacetate to beta-hydroxybutyrate by beta-hydrozybutyrate dehydrogenase. The calcium salt of HMB is the most used chemical form in dietary supplements, being the most common dose 3 g of HMB/day. Studies in humans and animals provide evidence that there are no adverse effects associated with HMB supplementation. Conclusion: Metabolic effects and lack of toxicity of HMB make it an adequate compound to be used as a dietary supplement (AU)

El B-hidroxi-B-metilbutirato (HMB) como suplemento nutricional (II): mecanismos de acción moleculares y celulares / B-hydroxy-B-metilbutirato as a dietary supplement (II): celland molecular mechanism of action

Introducción: En los últimos años el β-hidroxi-β-metilbutirato (HMB) ha sido foco de diversas investigaciones que le atribuyen un efecto sobre la disminución de la proteólisis muscular y un incremento de la masa muscular. Por tanto, se han realizado estudios centrados en los mecanismos celulares y moleculares responsables de dichos efectos. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se presentan los resultados referentes a los mecanismos de acción del HMB. Resultados: No existen suficientes datos que apoyen que la ingesta de HMB incremente la síntesis de colesterol en el músculo. Es posible que existan efectos positivos en el metabolismo muscular a través de la vía mTOR y del sistema ubiquitin-proteasoma, aunque no se conoce su mecanismo de acción. Probablemente, el HMB eleva los niveles sanguíneos de βhidroxibutirato y esto podría explicar sus principales efectos sobre la disminución de la proteólisis muscular. Conclusiones: De acuerdo a nuestros resultados, la posibilidad de justificar la acción del HMB a través de la vía del beta-hidroxibutirato abre una interesante línea de investigación para futuros estudios (AU)

Introduction: In recent years, several investigations have related β-hydroxy-β-methylbutyrate (HMB) to a reduced muscle proteolysis and to an increase in muscle mass. Therefore, a number of studies focused on the cellular and molecular mechanisms regulating these effects have been carried out. Aims: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. Methods: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. Results were divided into two parts; this article presents aspects referring to HMB mechanisms of action. Results: There is insufficient evidence that HMB intake increases muscle cholesterol synthesis. It probably has positive effects on muscle metabolism through both the mTOR and ubiquitin-proteasome pathways, although the mechanism of action is unknown. HMB may increase blood levels of β-hydroxybutyrate and this couldexplain the main effects of HMB on muscle proteolysis. Conclusion: According to these results, the possibility of justifying the action of HMB through the beta-hydroxybutyrate pathway opens an interesting line of research for future studies (AU)

[ß-hydroxy-ß-methylbutyrate as a dietary supplement (I): metabolism and toxicity]. / El ß-hidroxi-ß-metilbutirato (HMB) como suplemento nutricional (I): metabolismo y toxicidad.

INTRODUCTION: -hydroxy--methylbutyrate (HMB) is a leucine metabolite produced from -ketoisocaproic acid. HMB supplementation has been used as a dietary supplement in sports since 1997, with the aim of decreasing muscle proteolysis. In recent years, positive effects have been reported in different pathologies, which suggests potential health benefits. AIMS: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. METHODS: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. RESULTS were divided into two parts; this article presents the results about both HMB metabolism and possible toxicity. RESULTS: Studies show that HMB is related to cholesterol metabolism in skeletal muscle, which could reduce proteolysis, through hydroxy-methyl-glutaryl-coenzyme A and mevalonate as a precursor in the synthesis of cholesterol. However, HMB could also be transformed from acetoacetate to beta-hydroxybutyrate by beta-hydrozybutyrate dehydrogenase. The calcium salt of HMB is the most used chemical form in dietary supplements, being the most common dose 3 g of HMB/day. Studies in humans and animals provide evidence that there are no adverse effects associated with HMB supplementation. CONCLUSION: Metabolic effects and lack of toxicity of HMB make it an adequate compound to be used as a dietary supplement.

Introducción: El -hidroxi--metilbutirato (HMB) es un metabolito de la leucina producido a partir del ácido -cetoisocaproico. El HMB se utiliza como suplemento nutricional en el deporte desde 1997, atribuyéndosele una disminución de la proteólisis muscular. En los últimos años, se han descrito efectos positivos del HMB en diversas patologías, lo cual aumenta su probable utilidad para la mejora de la salud. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se abordan el metabolismo y la posible toxicidad del HMB. Resultados: Diversos estudios relacionan al HMB con el metabolismo del colesterol en el músculo esquelético, probablemente reduciendo la proteólisis, a través del 3-hidroxi-3-metilglutaril-coenzima A, que se transforma a mevalonato, actuando como precursor en la síntesis de colesterol. Sin embargo, el HMB podría transformarse en beta-hidroxi-butirato a través del metabolismo del acetoacetato, por medio de la beta-hidroxibutirato dehidrogenasa. Por otra parte, la forma química más habitual en los suplementos nutricionales es la sal de calcio de HMB y la dosis más utilizada, de 3 g de HMB/día. Los estudios realizados en humanos y en animales muestran que no existen efectos adversos por el consumo de HMB. Conclusiones: Los efectos metabólicos y la ausencia de toxicidad del HMB lo hacen adecuado para su uso como suplemento nutricional.

[ß-hydroxy-ß-methylbutyrate as a dietary supplement (II): cell and molecular mechanism of action]. / El ß-hidroxi-ß-metilbutirato (HMB) como suplemento nutricional (II): mecanismos de acción moleculares y celulares.

INTRODUCTION: In recent years, several investigations have related -hydroxy--methylbutyrate (HMB) to a reduced muscle proteolysis and to an increase in muscle mass. Therefore, a number of studies focused on the cellular and molecular mechanisms regulating these effects have been carried out. AIMS: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. METHODS: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. RESULTS were divided into two parts; this article presents aspects referring to HMB mechanisms of action. RESULTS: There is insufficient evidence that HMB intake increases muscle cholesterol synthesis. It probably has positive effects on muscle metabolism through both the mTOR and ubiquitin-proteasome pathways, although the mechanism of action is unknown. HMB may increase blood levels of -hydroxybutyrate and this could explain the main effects of HMB on muscle proteolysis. CONCLUSION: According to these results, the possibility of justifying the action of HMB through the beta-hydroxybutyrate pathway opens an interesting line of research for future studies.

Introducción: En los últimos años el -hidroxi--metilbutirato (HMB) ha sido foco de diversas investigaciones que le atribuyen un efecto sobre la disminución de la proteólisis muscular y un incremento de la masa muscular. Por tanto, se han realizado estudios centrados en los mecanismos celulares y moleculares responsables de dichos efectos. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se presentan los resultados referentes a los mecanismos de acción del HMB. Resultados: No existen suficientes datos que apoyen que la ingesta de HMB incremente la síntesis de colesterol en el músculo. Es posible que existan efectos positivos en el metabolismo muscular a través de la vía mTOR y del sistema ubiquitin-proteasoma, aunque no se conoce su mecanismo de acción. Probablemente, el HMB eleva los niveles sanguíneos de hidroxibutirato y esto podría explicar sus principales efectos sobre la disminución de la proteólisis muscular. Conclusiones: De acuerdo a nuestros resultados, la posibilidad de justificar la acción del HMB a través de la vía del beta-hidroxibutirato abre una interesante línea de investigación para futuros estudios.

Effects of creatine supplementation in taekwondo practitioners.

INTRODUCTION: Taekwondo (TKD) is a combat sport, which has also been proposed as a fitness program, with a strong anaerobic component. Creatine (Cr) supplementation is used to improve both anaerobic exercise performance and body composition. Therefore, Cr supplementation could be beneficial in TKD. AIMS: To determine the effect of Cr supplementation (50 mg/kg body wt) on body composition, anaerobic power and blood chemistry in young male TKD practitioners. METHODS: Ten male TKD practitioners (age [20 ± 2 yr], height [1.69 ± 0.06 m], and mass [67 ± 9.8 kg]) participated in a placebo-controlled, double blind, crossover study. Body composition (DEXA), anaerobic power (Wingate Test), blood lactate and blood chemistry were measured before and after supplementation. Differences between data before and after supplementation were calculated for each treatment (Cr and Placebo) and were compared using the Wilcoxon signed-rank test. RESULTS: Fat mass (kg) decreased after placebo (Mdn [IqR] = -0.75 [-1.44 to 0.03]) and increased following Cr intake (0.17 [-0.77 to 1.13] kg) (Z = 2.191, p < 0.028, r = 0.49). Serum triglyceride concentration (mg/mL) increased after Cr (45.00 [-7.50 to 75.00]) and decrease with placebo (-7.00 [-10.75 to 12.00]) (Z = 2.090, p < 0.037, r = 0.47). No changes were found in others parameters. CONCLUSION: Cr supplementation may increase fat mass and serum triglycerides concentration in young male TKD practitioners without improvement in anaerobic power. Cr supplementation appears to be safe, but athletes should be careful when they want to loss fat.

Introducción: El Taekwondo (TKD) es un arte marcial, que ha sido propuesto también en programas de actividad física, con un fuerte componente anaeróbico. La suplementación con creatina (Cr), utilizada para mejorar el rendimiento deportivo y la composición corporal, puede ser beneficiosa en TKD. Objetivos: Determinar el efecto de la suplementación de Cr sobre la composición corporal, potencia anaeróbica y bioquímica sanguínea en practicantes jóvenes de TKD. Métodos: Diez practicantes varones de TKD (edad [20 ± 2 AÑOs], estatura [1,69 ± 0,06 m], peso [67,0 ± 9,8 kg]) participaron en un ensayo aleatorizado cruzado (grupo control + placebo). Se evaluaron (pre-post suplementación) la composición corporal (DEXA), la potencia anaeróbica (Test de Wingate), el lactato y la bioquímica sanguínea. Se calculó la diferencia entre los valores pre y post ingestión para ambos tratamientos (Cr y placebo) y se compararon las diferencias usando la prueba de signos y rangos de Wilcoxon. Resultados: La masa grasa (kg) disminuyó después del placebo (Mdn [IqR] = -0,75 [-1,44 a 0,03]) mientras que con Cr se elevó significativamente (0,17 [-0,77 a 1,13] kg) (Z = 2,191, p < 0,028, r = 0,49). La concentración sanguínea de triglicéridos (mg/mL) aumentó con Cr (45,00 [- 7,50 a 75,00]) y disminuyó con Placebo (-7,00 [-10,75 a 12,00]) (Z = 2,090, p < 0,037, r = 0,47). No hubo cambios significativos en otros parámetros. Conclusiones: La suplementación con creatina puede incrementar la masa grasa y la concentración sanguínea de triglicéridos en jóvenes practicantes de TKD, sin mejorar la potencia anaerobia. La suplementación parece ser segura, pero es necesario ser cuidadosos cuando se busca disminuir el peso corporal.