Skinfolds compressibility and digital caliper's time response in skinfold measurement in male and female young adults.

BACKGROUND: The skinfold caliper reading of the skinfold thickness depends on its dynamic compressibility. This has led to the fact that, while it is indicated that skinfold readings should be taken when the reading is stable, there is no consensus on at what second the reading should be taken after the application of the skinfold caliper. The new Lipowise PRO digital skinfold caliper was used to analyze the evolution of skinfold readings under skinfold caliper pressure. The aim of the present investigation were: a) to analyze the evolution of the reading time of individual skinfolds when subjected to skinfold caliper pressure and when the skinfold reading reaches stability; b) to describe the physical behavior of skinfold tissues' time response to skinfold caliper pressure, and to explore differences between sites and subjects' skinfolds compressibility; and c) to analyze the sex differences in both the reading and the evolution of the skinfold over time. METHODS: A descriptive cross-sectional design was followed with a convenience sample of 165 healthy young adults (79 males and 86 females), with eight skinfolds measured using the Lipowise PRO skinfold caliper. The Lipowise PRO skinfold caliper uses a programmable reading time allowing for the measurement of the skinfold's thickness at a rate of 100 times per second, and monitoring skinfold behavior over the 3-second measurement period, thereby enabling the assessment of the tissue response to the constant force exerted by the skinfold caliper jaws. RESULTS: All skinfolds showed statistical differences in terms of compressibility characteristics (p < 0.001). Significant differences were found between measurement time points for individual skinfolds and sum of skinfolds (p < 0.001-0.025). Stabilization being found depending on the skinfold measured from 1.5 seconds for biceps, subscapular, iliac crest, supraspinale, abdominal, and thigh skinfolds; 2.0 seconds for ∑6 and ∑8 skinfolds; and 2.5 seconds for triceps and calf skinfolds. It was observed an effect of sex on this issue (p < 0.001-0.030). More specifically, in the case of males, the supraspinale and abdominal skinfolds stabilized after 1.5 seconds; the calf skinfold and ∑6 and ∑8 skinfolds stabilized after 2 seconds; while the rest of the skinfolds did not stabilize until 3 seconds. In the case of females, no stabilization of the triceps skinfold was found, while the rest of the individual skinfolds and the ∑6 and ∑8 skinfolds stabilized from 1.5 seconds. A regression analysis indicated that skinfold thickness could be predicted based on measurement time in 50-77% of the cases (p = 0.001). CONCLUSION: A skinfold caliper application, using the digital caliper Lipowise PRO, of three seconds may be sufficient for achieving stability in the measurement and for obtaining the minimum value for most individual and sum of skinfolds. However, there are certain skinfolds that may require more time when performed on certain individuals, which vary according to sex.

Birth weight, skeletal maturity and dietary patterns are associated with body composition compartments differently in male and female physically active adolescents.

Background: Adequate body composition is important for health and performance of physically active adolescents; however, some factors can influence body composition. Aim: The purpose of this study was to evaluate the association between body composition and birth weight, skeletal maturity and dietary patterns, in male (n = 124) and female (n = 107) physically active adolescents. Methods: Birth weight was obtained from health booklets. Dual-energy X-ray absorptiometry (DXA) was used to estimate fat mass (FM), fat-free mass (FFM), visceral adipose tissue (VAT) and abdominal adipose tissue (ASAT). Skeletal maturity was assessed by a hand and fist scanner using DXA. Food intake was assessed using a food frequency questionnaire and dietary patterns by factorial analysis. Results: Seventy one percent (male = 16%, female = 55%) of the participants were mature. Two dietary patterns (in natura/minimally processed and processed/ultra-processed) were identified. In males, FM (>15%, P = 0.043) and ASAT (>30%, P = 0.042) were higher in those with low-median compared to high-median birth weight. FFM (>24%) was higher in skeletally mature compared to those immatures (P = 0.001), and VAT (>28%) was higher in processed/ultra-processed compared to in natura/minimally processed dietary patterns (P = 0.015). In females, FFM (>9%) was higher in those with low-median compared to high-median birth weight (P = 0.019); and FFM (>16%), FM (>28%) and ASAT (>45%) were higher in skeletally mature compared to those immatures (P = 0.001). Conclusion: Our results may contribute to a better understanding of the complex association among body composition, birth weight, skeletal maturity and dietary patterns and in physically active adolescents, differently according to sex.

Anthropometric characteristics and physical activity level of Orienteers: a pilot study / Características antropométricas e nível de atividade física de Orientistas: um estudo piloto

Abstract The present study aimed to describe a study protocol for Orienteers' anthropometric characteristics and physical activity level. This is an individualized, observation and cross-sectional pilot study, that has encompassed three Orienteers (2 Portuguese men and 1 Spanish woman) with mean age 22.6 ± 3.78 years and 8.0 ± 2.64 consecutive years of Orientation practice. In total, 26 anthropometric variables were assessed: four basic measurements, nine skinfolds, nine girths and four breadths; Body Mass Index was calculated, as well as body composition and somatotype (according to the Heath-Carter method). The International Physical Activity Questionnaire - Short Form was used to obtain the score expressed as metabolic equivalent and the energy expenditure in kilocalories, both during the reference week. Mean somatotype recorded for Orienteering athletes could be defined as balanced mesomorph. Scores recorded for different physical activity/ inactivity expressed domains have shown high-energy expenditure. Sports Science Professionals can use the herein proposed protocol to improve Orienteers' training.

Resumo Objetivou-se descrever um protocolo de estudo das características antropométricas e do nível de atividade física de Orientistas. Trata-se de um estudo piloto, caracterizado como individualizado, observacional e transversal. Participaram do estudo três Orientistas (2 homens Portugueses e 1 mulher Espanhola) com 22,6 ± 3,78 anos de idade e 8,0 ± 2,64 anos de prática consecutiva de Orientação. Foram avaliadas 26 variáveis antropométricas: quatro medidas básicas, nove dobras cutâneas, nove circunferências e quatro diâmetros ósseos; Índice de Massa Corporal foi calculado, bem como a composição corporal e o somatotipo (de acordo com o método Heath-Carter). O Questionário Internacional de Atividade Física, versão curta e auto-administrado, foi utilizado para obter a pontuação expressa como equivalente metabólico e o dispêndio energético em quilocalorias, ambos durante a semana de referência. A média do somatotipo dos atletas de Orientação pode ser definida como mesomorfo balanceado. As pontuações dos diferentes domínios da atividade física/ inatividade expressas, demonstraram um elevado dispêndio energético. Profissionais das Ciências do Esporte podem usar o protocolo proposto para melhor controle do treinamento de Orientistas.

Differences between Four Skinfold Calipers in the Assessment of Adipose Tissue in Young Adult Healthy Population.

Background: The aim of this study was to analyze the validity of four different skinfold calipers, as well as to establish the differences between them in a healthy young adult population. Methods: The present study followed a cross-sectional design, including 138 participants, with 69 males (21.46 ± 2.52 years) and 69 females (22.19 ± 2.85 years). The measurement protocol included basic measurements of body mass and stretch stature and eight skinfolds with a Harpenden, Holtain, Slim Guide, and Lipowise. The ∑6 and ∑8 skinfolds and fat mass were calculated. The order in which the skinfold calipers were used was randomized. Results: No significant differences were found in either the Σ6 and Σ8 skinfolds or masses and fat percentages calculated with the skinfolds obtained with the different calipers (p > 0.05), and the inclusion of the covariates of sex, BMI, and hydration status of the participants showed no effect on the differences. The Bland−Altman test showed significant differences between the calipers (p < 0.001). Conclusion: It has been observed that the analyzed calipers have shown validity for the assessment of adiposity-related variables in a male and female sample of non-overweight, young healthy adults, but they are not interchangeable with each other when the assessment is meant to be compared over time or with other samples.

Fat-free mass in adolescent athletes: Accuracy of bioimpedance equations and identification of new predictive equations.

OBJECTIVES: The aims of this study were to evaluate the effect of biological maturity on body composition in Brazilian adolescent athletes, to verify the accuracy of previous bioimpedance predictive equations for estimating fat-free mass (FFM), and to develop new predictive equations, considering sexual and skeletal maturity. METHODS: There were 318 Brazilian adolescent athletes (52% male) involved in this study. FFM was determined using single-frequency (50 kHz) bioelectrical impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA), which was used as the reference method. The adolescents were classified into skeletally mature using bone age (both sexes), and sexually mature using menarche occurrence (female). The effect of maturity on bioelectrical values was tested using bioelectrical impedance vector analysis. Three predictive BIA equations to estimate FFM were selected from the reviewed literature. Lin's concordance correlation coefficient and Bland-Altman test were used to test the concordance and accuracy of BIA equations. Stepwise multiple regression was used to develop new predictive equations, considering BIA vectors, age, skeletal, and sexual maturity. RESULTS: DXA and BIA results showed wide limits of disagreement for FFM for all the three equations. Two new equation models were developed, including age and skeletal maturity for both sexes and menarche status for females. Both models showed high R2 (males = 0.92 and females = 0.84). CONCLUSIONS: The assessment of body composition in adolescent athletes should consider sexual (female) or skeletal (male) maturity. The newly proposed equations showed promising results in Brazilian adolescent athletes. A test in different groups and populations is necessary to evaluate the general suitability of the equations in adolescents.

Three-dimensional kinematic adaptations of gait throughout pregnancy and post-partum.

PURPOSE: The kinematic analysis of gait during pregnancy provides more information about the anatomical changes and contributes to exercise and rehabilitation prescription. The purposes were to describe and quantify the spatial, temporal and kinematic parameters in the joints of the lower limb during gait at the end of the first, second and third trimesters of pregnancy and in the postpartum period. METHODS: A three-dimensional analysis was performed in eleven pregnant women. Repeated measures ANOVA was performed for comparisons between periods. RESULTS: The longitudinal effect of pregnancy was not observed in spatial and temporal parameters. In joint kinematics the effect of pregnancy was observed in all joints for the three planes of motion. The hip joint and pelvis are the structures with more changes, and the results point to an increase in the anterior tilt of the pelvis as the pregnancy progresses, as well as a decrease of the amplitudes of the hip joint. The results suggested that pregnant women need to maintain the stability of the body, and become more efficient in locomotion. CONCLUSIONS: In general, the results retrieve the values from the beginning of pregnancy, indicating that the body was self-organized in order to overcome the morphological and physiological changes which women suffer during pregnancy, indicating that they have the ability to adapt depending on the demands, and after the effect of pregnancy is over, they return to values similar to those found in early pregnancy.

Determinant factors of pain intensity in overweight and obese adults with knee osteoarthritis.

Osteoarthritis is one of the most disabling diseases, the main symptom being pain, which is associated with a low level of physical activity. The incidence and progression of knee osteoarthritis are directly related with risk factors such as obesity, age and mechanical factors. OBJECTIVE: The aim of this study was to identify which variables (physical activity, anthropometry and body composition of the lower limb) best predict pain intensity in obese individuals with knee osteoarthritis. METHODS: The sample consisted of 44 individuals of both genders (mean age 56.6 ± 6.6 yrs). Anthropometric measures of body mass, stature, mid-thigh, patellar and calf circumferences, and foot breadth were obtained. The body composition of the most painful lower limb was obtained by dual-energy X-ray absorptiometry in different regions: mid-thigh; patella; calf and foot. For each of these regions, fat mass percentage, the amount of fat and fat-free mass, bone mass and bone mineral density were evaluated. Physical activity was assessed by the International Physical Activity Questionnaire (short version) and pain intensity with the numeric rating scale. Data analysis was done using the multifactorial logistic regression (backward conditional method). RESULTS: The multifactorial analysis showed that gender (Odds Ratio of 7.448 for a 95% Confidence Interval of [1.032 - 53.747]) and foot breadth (Odds Ratio of 3.730 for a 95% Confidence Interval of [1.006 - 13.827]) are important factors to explain the risk of pain. CONCLUSIONS: These results seem to indicate that the assessment of foot morphology must be considered in knee osteoarthritis studies, since foot breadth is a predictor of knee pain. Further research is required to investigate the influence of foot morphology as well as of the use of insoles, splints or adapting shoes, on obese individuals with knee osteoarthritis.

Influence of Body Composition on Gait Kinetics throughout Pregnancy and Postpartum Period.

Pregnancy leads to several changes in body composition and morphology of women. It is not clear whether the biomechanical changes occurring in this period are due exclusively to body composition and size or to other physiological factors. The purpose was to quantify the morphology and body composition of women throughout pregnancy and in the postpartum period and identify the contribution of these parameters on the lower limb joints kinetic during gait. Eleven women were assessed longitudinally, regarding anthropometric, body composition, and kinetic parameters of gait. Body composition and body dimensions showed a significant increase during pregnancy and a decrease in the postpartum period. In the postpartum period, body composition was similar to the 1st trimester, except for triceps skinfold, total calf area, and body mass index, with higher results than at the beginning of pregnancy. Regression models were developed to predict women's internal loading through anthropometric variables. Four models include variables associated with the amount of fat; four models include variables related to overall body weight; three models include fat-free mass; one model includes the shape of the trunk as a predictor variable. Changes in maternal body composition and morphology largely determine kinetic dynamics of the joints in pregnant women.

Three-Dimensional Kinetic Adaptations of Gait throughout Pregnancy and Postpartum.

Biomechanical adaptations that occur during pregnancy can lead to changes on gait pattern. Nevertheless, these adaptations of gait are still not fully understood. The purpose was to determine the effect of pregnancy on the biomechanical pattern of walking, regarding the kinetic parameters. A three-dimensional analysis was performed in eleven participants. The kinetic parameters in the joints of the lower limb during gait were compared at the end of the first, second, and third trimesters of pregnancy and in the postpartum period, in healthy pregnant women. The main results showed a reduction in the normalized vertical reaction forces, throughout pregnancy, particularly the third peak. Pregnant women showed, during most of the stance phase, medial reaction forces as a motor response to promote the body stability. Bilateral changes were observed in hip joint, with a decrease in the participation of the hip extensors and in the eccentric contraction of hip flexors. In ankle joint a decrease in the participation of ankle plantar flexors was found. In conclusion, the overall results point to biomechanical adjustments that showed a decrease of the mechanical load of women throughout pregnancy, with exception for few unilateral changes of hip joint moments.

Comparison between overweight due to pregnancy and due to added weight to simulate body mass distribution in pregnancy.

The assessment of biomechanical loading in the musculoskeletal system of the pregnant women is particularly interesting since they are subject to morphological, physiological and hormonal changes, which may lead to adaptations in gait. The purpose of this study was to analyze the effect of the increased mass in the trunk associated to pregnancy on the lower limb and pelvis, during walking, on temporal-distance parameters, joint range of motion and moments of force, by comparing a pregnant women group to a non-pregnant group, and to this group while carrying a 5 kg additional load located in the abdomen and breasts during walking, to understand which gait adaptations may be more related with the increased trunk mass, or if may be more associated with other factors such as the girth of the thigh. The subjects performed a previous 12 min training adaption to the added load. To calculate ankle, knee and hip joint angles and moments of force, a three-dimensional biomechanical model was developed. The inverse dynamics method was used to estimate net joint moments of force. The increased mass of the anterior trunk associated with second trimester of pregnancy may influence some gait variables such as the left step time, left and right stance times, double limb support time, maximum hip extension, maximum pelvic right obliquity, pelvic obliquity range of motion, maximum transversal left rotation and peak hip flexion moments of force.

Body composition in portuguese adolescents: are physical activity and maturity status sex-specific determinant factors? / Composição corporal em adolescentes portugueses: a atividade física e a maturidade são fatores determinantes específicos do sexo?

The influence of biological maturation and physical activity (PA) on the differences of body composition in adolescents have been little studied. The purpose of this study was to examine if PA and maturity status were sex-specific determinant factors in the adolescents' body composition. Ninety-four adolescents (50 boys and 44 girls) were evaluated. All anthropometric measures were obtained according to ISAK procedures, bone age was estimated by the TW3 method, and PA was assessed with Actigraph (r) GT1M, over seven consecutive days. Maturity status explained 33% of the body mass index (BMI) and waist circumference (WC) and 31% of the sagittal abdominal diameter (SAD) in boys. In girls, maturity status explained 27% of the waist-to-hip ratio (WHR), moderate PA explained 17% of the BMI and 12% of the WC, and moderate to vigorous PA explained 11% of the SAD. These results seem to indicate that the determinant factors of the adolescents' body composition are sex-specific. Maturity status was the main predictive factor in boys and interacted with PA in girls. Our findings support the evidence that researchers need to consider biological maturity when explaining body composition changes in adolescents.

A influência da maturação biológica e atividade física (AF) nas diferenças de composição corporal em adolescentes tem sido pouco estudada. O objetivo deste estudo foi examinar se, na composição corporal dos adolescentes, a AF e a maturidade eram fatores determinantes específicos do sexo. Foram avaliados noventa e quatro adolescentes (50 meninos e 44 meninas). Todas as medidas antropométricas foram obtidas de acordo com os procedimentos do ISAK, a idade óssea foi estimada pelo método TW3 e a AF foi avaliada com o Actigraph (r) GT1M, durante sete dias consecutivos. A maturidade explicou 33% do índice de massa corporal (IMC) e da circunferência da cintura (CC) e 31% do diâmetro abdominal-sagital (DAS), nos rapazes. Nas raparigas, a maturidade explicou 27% do índice cintura-anca (ICA), a AF moderada explicou 17% do IMC e 12% da CC e, a AF moderada-a-vigorosa explicou 11% do DAS. Estes resultados parecem indicar que os fatores determinantes da composição corporal dos adolescentes são específicos do sexo. A maturidade foi o principal fator preditivo nos rapazes e, em conjunto com a AF moderada, nas raparigas. Os nossos resultados suportam a evidência de que os investigadores precisam considerar a maturidade biológica quando explicam as alterações da composição corporal nos adolescentes.

Biomechanics of gait during pregnancy.

INTRODUCTION: During pregnancy women experience several changes in the body's physiology, morphology, and hormonal system. These changes may affect the balance and body stability and can cause discomfort and pain. The adaptations of the musculoskeletal system due to morphological changes during pregnancy are not fully understood. Few studies clarify the biomechanical changes of gait that occur during pregnancy and in postpartum period. PURPOSES: The purpose of this review was to analyze the available evidence on the biomechanical adaptations of gait that occur throughout pregnancy and in postpartum period, specifically with regard to the temporal, spatial, kinematic, and kinetic parameters of gait. METHODS: Three databases were searched and 9 studies with a follow-up design were retrieved for analysis. RESULTS: Most studies performed temporal, spatial, and kinematic analysis. Only three studies performed kinetic analysis. CONCLUSION. The adaptation strategies to the anatomical and physiological changes throughout pregnancy are still unclear, particularly in a longitudinal perspective and regarding kinetic parameters.

The PICO project: aquatic exercise for knee osteoarthritis in overweight and obese individuals.

BACKGROUND: Aquatic exercise is recommended by the Osteoarthritis Research Society (OARSI), by the American College of Rheumatology (ACR) and by the European League Against Rheumatism (EULAR) as a nonpharmacological method of controlling the knee osteoarthritis (KOA) symptoms. Moreover, given that weight loss results in a reduction of the load that is exerted upon the knee during daily activities, obesity is also considered to be a modifiable risk factor for the development and or exacerbation of KOA. The implementation of an exercise based weight loss program may, however, itself be limited by the symptoms of KOA. The aquatic program against osteoarthritis (termed "PICO" in Portuguese) prioritizes the control of symptoms and the recovery of functionality, with an attendant increase in the patient's physical activity level and, consequently, metabolic rate. Our laboratory is assessing the effectiveness of 3 months of PICO on the symptoms of KOA, on physical function, on quality of life and on gait. In addition, PICO shall examine the effects of said exercise intervention on inflammatory biomarkers, psychological health, life style and body composition. METHODS/DESIGN: The trial is a prospective, single-blinded, randomized controlled trial, and involves 50 overweight and obese adults (BMI = 28-43.5 kg/m²; age 40-65 yrs) with radiographic KOA. The participants are randomly allocated into either an educational attention (control) group or an aquatic (exercise program) group. This paper describes the experimental protocol that is used in the PICO project. DISCUSSION: The PICO program shall provide insight into the effectiveness of an aquatic exercise program in the control of KOA symptoms and in the improvement of the quality of life. As such, they are likely to prove a useful reference to health professionals who intend to implement any kind of therapeutic intervention based around aquatic exercise. TRIAL REGISTRATION: NCT01832545.

Kinematic analysis of gait in the second and third trimesters of pregnancy.

The kinematic analysis of gait during pregnancy provides more information about the anatomical changes and contributes to exercise and rehabilitation prescription. The purposes were to quantify the lower limb kinematics of gait and to compare it between the second and third trimesters of pregnancy and with a control group. A three-dimensional analysis was performed in twenty-two pregnant women and twelve nonpregnant. Repeated Measures and Manova tests were performed for comparisons between trimesters and between pregnant and controls. The walking speed, stride width, right-/left-step time, cycle time and time of support, and flight phases remain unchanged between trimesters and between pregnant and controls. Stride and right-/left-step lengths decreased between trimesters. Double limb support time increased between trimesters, and it increased when compared with controls. Joint kinematics showed a significant decrease of right-hip extension and adduction during stance phase between trimesters and when compared with controls. Also, an increase in left-knee flexion and a decrease in right-ankle plantarflexion were found between trimesters. The results suggested that pregnant women need to maintain greater stability of body and to become more efficient in locomotion. Further data from the beginning of pregnancy anthropometric data may contribute to the analysis.

Análise de equações preditivas da gordura corporal em jovens atletas de "taekwondo" / Analysis of predictive equations of body fat in young taekwondo athletes / Análisis de ecuaciones predictivas de la grasa corporal en atletas jóvenes de taekwondo

Devido à falta de métodos acessíveis válidos para mensurar o percentual de gordura corporal (%G) de taekwondistas adolescentes (TKDA), objetivou-se analisar seis equações antropométricas de predição do %G, em cinco TKDA (12,23 anos ± 1,60), utilizando como método de referência a Densitometria Radiológica de Dupla Energia (DEXA). Os %G estimados pelas equações foram comparados pelo teste t-student, regressão linear e Bland e Altman (B&A) com os obtidos por DEXA. Apenas a equação de Slaughter et al. (1988) foi adequada pelo cálculo amostral, e embora tenha subestimado o %G (em 4,85% ± 0,98), esta apresentou alta correlação (R = 0,935; R² = 0,874 EPE = 1,01) e baixa amplitude nos limites de concordância a 95% (3,84%) pelo B&A em comparação com a DEXA. Portanto, esta equação mostrou-se adequada para a predição do %G em TKDA, desde que seja corrigida pela equação de ajuste [%G (DEXA) = 1,64 + 1,24 • %G (Eq 4)] gerada pela regressão linear.

Due to the lack of valid and accessible tests to measure the body fat percentage (BF%) of adolescent taekwondo athletes (TKDA), this study aimed to analyze six anthropometric equations in the prediction of BF% with the Dual-Energy-x-Ray (DEXA) as referential method for five TKDA (12.23 years ± 1.60). The BF% estimated by the equations were compared with DEXA values using the t-student , linear regression and Bland & Altman (B&A) tests. Only the equation of Slaughter et al. (1988) was adequated by the sample size calculation, and although it subestimated the BF% (in 4.85% ± 0.98), it showed a high correlation (R = 0.935; R² = 0.874 EPE = 1.01) and low amplitude in the limits of agreement at 95% (3.84%) by B&A in comparison to DEXA. However, this equation is adequated to predict the BF% in TKDA, if it's corrected by the adjustement equation [%G (DEXA) = 1,64 + 1,24•%G (Eq 4)] generated by linear regression.

Debido a la falta de métodos accesibles válidos para medir el porcentaje de grasa del cuerpo (%G) de atletas de taekwondo adolescentes (TKDA), destinada a analizar seis ecuaciones antropométricas de predicción de %G, en cinco TKDA (12,23 años ± 1,60 ), utilizando como método de referencia la Densitometría Radiológica de Energía Dual (DEXA). El %G estimado por las ecuaciones fue comparado mediante la prueba t-student, regresión lineal y Bland & Altman (B&A) con los que se obtienen mediante DEXA. Sólo la ecuación del SLAUGHTER et al. (1988) fue adecuada para el cálculo del tamaño de la muestra y, a pesar de que había subestimado la %G (4,85 % ± 0,98 ), este mostró una alta correlación (R = 0,935 ; R2 = 0,874 EPE = 1,01 ) y baja amplitud dentro de los límites de concordancia con el 95% (3,84 %) por B&A en comparación con la DEXA. Por lo tanto, esta ecuación demostró ser adecuada para la predicción de %G en TKDA, desde que corrigida mediante la siguiente ecuación de ajuste [ %G (DEXA) = 1,64 + 1,24 • %G (eq 4)] generada mediante regresión lineal.

Anthropometric profiles of elite older triathletes in the Ironman Brazil compared with those of young Portuguese triathletes and older Brazilians.

The objective of this study was to describe the anthropometric profiles of elite older triathletes participating in the 2009 Ironman Brazil and to compare their somatotype, anthropometric and body composition characteristics with those of elite young triathletes and older non-athletes. The sample consisted of 64 males, divided into three groups: (1) older triathletes (n = 17), (2) young triathletes (n = 24), and (3) older non-athletes (n = 23). Somatotype was analysed according to the Carter and Heath ( 1990 ) method. Body mass index, sum of four skinfolds, percentage body fat, body fat mass, and fat-free mass were also estimated. Older non-athletes had higher endomorphy, sum of four skinfolds, fat percentage, and body fat mass than the athletes. Older athletes who participated in the Ironman and elite young triathletes had higher fat-free mass than older non-athletes. Older triathletes and older non-athletes were considered mainly endomorphic mesomorphs and young triathletes mainly ectomorphic mesomorphs. The findings that characterize the anthropometric profile of athletes in this sports modality could be used as a reference.

Crossing safety barriers: influence of children's morphological and functional variables.

Thirty-three children between 3 and 6 years of age were asked to climb four different types of safety barriers. Morphological and functional variables of the children, which were expected to influence climbing or passing through skills, were collected. The influence of those variables on children's success rate and time to cross was tested. No barrier offered a total restraining efficacy. The horizontal bars barrier was crossed by 97% of the children. In the group of children that succeeded in crossing the four barriers, mean time to cross the most difficult barrier was 15 s. Age was the best predictor for success in crossing most barriers but morphology and strength were important predictors of time to cross. The influence of anthropometric variables in time to cross was dependent upon the characteristics of the barrier. A good design of safety barriers should consider children's age, morphology and strength.

The role of lean body mass and physical activity in bone health in children.

In the context of physical education curricula, markers of physical fitness (e.g., aerobic capacity, muscular strength, flexibility, and body mass index or body fat) are usually evaluated in reference to health standards. Despite their possible mediating role in the relationship between weight-bearing or muscle forces and features of bone tissue, these attributes of fitness may not be the most relevant to predict skeletal health. It is therefore important to analyze the relative contribution of these factors to the variability in bone tissue of different parts of the skeleton, and to analyze it by gender, as sensitivity to mechanical loading can diverge for boys and girls. We compared the effects of habitual physical activity (PA) and lean mass, as surrogates of weight-bearing and muscle forces, and of physical fitness (aerobic and muscle capacity of lower and upper limbs) on bone mineral content (BMC) and size of total body, lumbar spine, femoral neck, and 1/3 radius in 53 girls and 64 boys from 7.9 to 9.7 years of age. After controlling for bone age, body mass, body height, and calcium intake, lean mass was the most important predictor of bone size and/or mineral in both genders (p < 0.05), while habitual weight-bearing PA positively influenced BMC in boys (p < 0.05). The effect of muscle in bone was not determined by PA and fitness score did not explain bone variability. Femoral neck was the bone site more closely associated with mechanical loading factors; boys with a PA > 608 counts/min/day (~105 min/day of moderate and vigorous intensity) showed 13-20% more BMC than those with less physical activity, and girls with a lean mass >19 kg showed 12-19% more BMC than those with less lean mass. These findings suggest that lean mass was the most important predictor of bone size and/or mineralization in both genders, while habitual weight-bearing PA appears to positively impact on bone mineral in prepubertal boys and that both lean mass and PA need to be considered in physical education curricula and other health-enhancing programs.

Growth and nutritional status of Portuguese children from Lisbon, and their parents. Notes on time trends between 1971 and 2001.

AIM: To document time trends in growth and nutritional status among Portuguese children from Lisbon, and their parents. SUBJECTS AND METHODS: Two growth surveys were carried out in Lisbon, Portugal in 1991 and in 2001 at the request of the Municipality of Lisbon. The 1991 sample was composed of 2018 children (992 boys and 1026 girls) and the 2001 sample was composed of 3591 children (1787 boys and 1804 girls). The ages range from 4 to 11 years. The data from these surveys is compared with published data from 1971. Data on growth and nutritional status of the children and their parents were analysed. Nutritional status of the family clusters is also documented. RESULTS: There was an increase in the average height of the children between 1971 and 2001, but a more severe increase in overweight and obesity. Stunting in height was virtually non-existent among the children, but leg stunting (leg length relative to height) was high. The main changes between 1991 and 2001 are towards a greater prevalence of overweight/obese family clusters and dual-burden family clusters (at least one underweight member and one overweight/obese member). CONCLUSIONS: In this biological survey article we present two growth databases that may be used in future studies. There is an urgent need to conduct a national growth survey in Portugal, including all age groups, with stratified samples by district and ethnic diversity.