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It is well-established that at old age there is a significant decline in muscle strength. Reference values for muscle strength might be useful for assessment of muscle impairment and of physiological adaptations. However, it is still unclear whether gender affects the rate of decline. Therefore, the aim of this study is to investigate the effect of gender and age on handgrip strength and to establish reference values for this variable. Reviewing medical charts collected from 1994 to 2005, a convenience sample of 2,648 subjects (1,787 men and 861 women), aged between 18 and 90 years, was obtained. Our results show higher handgrip strength for men compared with women (36.8 +/- 0.20 vs. 21.0 +/- 0.18 kg; p < 0.001). The regression analysis with a quadratic model shows that aging accounts for 30% of the variance in handgrip strength (r super(2) = 0.30; p < 0.001) in men and 28% (r super(2) = 0.28; p < 0.001) in women. In addition, the bent linear regression with multiple regressors show that a faster decline in handgrip strength occurs at the age of 30 years for men and 50 years for women. We conclude that handgrip strength decline with age differs between genders, making useful the existence of distinct male and female normative age group data.

There is a growing interest in knowing the relationship between biological maturation and sport performance-related variables of young athletes. The objective of this study is to analyze the relationship between biological maturation, physical fitness, and kinanthropometric variables of athletes during their growing period, according to their sex. The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and the search protocol was registered in PROSPERO, code: CRD42020208397. A search through the PubMed, Web of Sciences, and EBSCO databases was performed. A total of 423 studies were screened and 13 were included in the meta-analysis. The meta-analysis was completed by using the mean and standard deviation of each variable according to each maturation status (early, on time, or late). Differences depending on maturation were found on physical fitness, with better results in the advanced maturational groups in the male population (standard mean difference (SMD) = 0.17–2.31; p < 0.001–0.05). Differences depending on maturation were found for kinanthropometric variables in males (SMD = 0.37–2.31; p < 0.001–0.002) and height and body mass in females (SMD = 0.96–1.19; p < 0.001). In conclusion, the early maturation group showed higher values in kinanthropometric variables and better results in physical fitness, highlighting the importance of the maturational process in the talent selection programs. Despite that, more research is needed to clarify the relationship of maturation with the other variables on female populations and the changes in the muscle and bone variables during the maturation processes of both sexes.

Objective: Analyze the anthropometric characteristics of Chilean professional soccer players divided according to the position they occupy in the field of play. Method: One hundred and fifty-eight (n = 158) professional soccer players divided into Archers (AR) Defenses (DEF) Volantes (VOL) and Forwards (FOR), with average Age values (24.2 ±4.76 years, body mass 75.0±7.28 kg and height 175.7±6.32 cm.), All belonging to the Ñublense Sports Club of the city of Chillan, Chile. An assessment of the body composition was made using the 5 component fractionation, somatotype, body mass index, sum of six skinfolds and the muscle-bone relationship, following the protocol of the International Society for the Advancements of Kinanthropometry. Results: Regarding body composition, mean values of Adipose Mass = 21.7%, Muscular Mass = 48.9%, Residual Mass = 12.4%, Bone Mass = 11.4% and Skin Mass = 5.2% were obtained. In relation to the somatotype, a balanced mesomorphic classification was obtained with mean values 2.5 - 5.4 - 2.1. Conclusion: According to the position they occupy on the pitch, the professional players of the Ñublense soccer club present a somatotype similar to that of other national and international soccer players, where the balanced mesomorphic component predominates. However, there is an increase in the percentages of adipose mass (AM) and a smaller stature, compared to international soccer players, which can determine clear differences in performance with respect to playing positions in competitive situations. Objetivo: Analizar las características antropométricas de futbolistas profesionales del club deportivo Ñublense divididos de acuerdo a la posición que ocupan en el campo de juego. Método: Participaron ciento cincuenta y ocho (n=158) jugadores profesionales de Futbol divididos en Arqueros (AR) Defensas (DEF) Volantes (VOL) y Delanteros (DEL), todos pertenecientes al Club Deportivo Ñublense de la ciudad de Chillan, Chile. Se realizó una valoración de la composición corporal utilizando el fraccionamiento en 5 componentes, somatotipo, índice de masa corporal, suma de seis pliegues cutáneos y la relación músculo-óseo, siguiendo el protocolo de la International Society for the Advancements of Kinanthropometry (ISAK). Resultados: En cuanto a la composición corporal se obtuvieron valores porcentuales de Masa Adiposa=21.7%, Masa Muscular=48.9%, Masa Residual=12.4%, Masa Osea=11.4% y Masa Piel=5.2%. En relación al somatotipo se obtuvo una clasificación mesomorfico balanceado con valores medios 2.5-5.4-2.1. Conclusión: Los jugadores profesionales del club de futbol Ñublense de acuerdo a la posición que ocupan en el terreno de juego, presentan un somatotipo similar al de otros futbolistas nacionales e internacionales, donde predomina el componente mesomórfico balanceado. Sin embargo, se observa una elevación de los porcentajes de masa adiposa (MA) y una menor talla, en comparación a futbolistas internacionales, lo que pueden determinar claras diferencias en el rendimiento respecto a las posiciones de juego en situaciones competitivas.

Assessment of skeletal muscle mass (SMM) is essential to monitor physical performance and health status. The most widely used anthropometric equations have repeatedly demonstrated to overestimate or underestimate SMM in different populations. Herein, we developed and cross-validated a new anthropometric regression equation for estimating SMM, using dual-energy X-ray absorptiometry (DXA) as the reference method. A group of 206 healthy Caucasian participants aged 18–65 years were included in the final analysis. Participants underwent a DXA scan, and body mass, stature, four skinfolds (biceps, triceps, subscapular, and supracrestal) and four breadths (femoral, humeral, ankle, and wrist) were assessed by an accredited anthropometrist. Accuracy was assessed by mean differences, coefficient of determination, standard error of the estimate (SEE), concordance correlation coefficient (CCC), and Bland–Altman plots. The proposed equation explained 91.3% of the variance in the DXA-derived SMM percentage, with a low random error (SEE = 1.95%), and a very strong agreement (CCC = 0.94). In addition, it demonstrated no fixed or proportional bias and a relatively low individual variability (3.84%). The new anthropometric equation can accurately predict SMM percentage in a Caucasian population with a wide age range (18–65 years).

Changes in body composition and specifically fat mass, has traditionally been used as a way to monitor the changes produced by nutrition and training. The objective of the present study was to analyse the differences between the formulas used to estimate fat mass and to establish the existing relationship with the body mass index and sums of skinfolds measurement in kinanthropometry. A total of 2458 active adults participated in the study. Body mass index (BMI) and skinfolds were measured, and the Kerr, Durnin-Womersley, Faulkner and Carter equations were used to assess fat mass. Significant differences were found between all the formulas for the percentage of fat mass, ranging from 10.70 ± 2.48 to 28.43 ± 5.99% (p < 0.001) and fat mass from 7.56 ± 2.13 to 19.89 ± 4.24 kg (p < 0.001). The correlations among sums of skinfolds and the different equations were positive, high and significant in all the cases (r from 0.705 to 0.926 p < 0.001), unlike in the case of BMI, were the correlation was lower and both positive or negative (r from −0.271 to 0.719; p < 0.001). In conclusion, there were differences between all the formulas used to estimate fat mass; thus, for the evaluation of fat mass with kinanthropometry of an active adult, the use of the same formula is recommended on all occasions when the results are going to be compared or when an athlete is compared with a reference.

This study aimed to (i) characterise the body composition of professional and semi-professional male futsal players, (ii) assess the validity of commonly used equations to estimate FM%, (iii) develop and cross-validate a futsal-specific FM% prediction equation. In a cross-sectional design, 78 adult male futsal players were assessed for body mass, stature, skinfolds, and girths as per the International Society for the Advancement of Kinanthropometry protocol and completed a dual-energy X-ray absorptiometry (DXA) scan for reference body composition data. Using paired-sample t-tests, the FM% from the DXA and nine published equations were compared. New sport-specific models were developed by stepwise multiple regression. Existing equations were cross-validated using the least squares regression, concordance correlation coefficient, and the Bland–Altman analyses. New equations were further cross-validated using the PRESS approach. None of the existing equations accurately predicted the DXA-derived FM% (p < 0.001; R2 ≤ 0.76, SEE ≥ 1.59; CCC ≤ 0.83; bias = −8.2% to −1.3%, limited agreement, and varying trends). The novel Bettery® equation: −0.620 + (0.159 ∗ Σ4SKF [triceps, abdominal, iliac crest, and front thigh (mm)]) + (0.120 ∗ waist girth (cm)), demonstrated a high accuracy (R2 = 0.85, SEE = 1.32%), a moderate strength of agreement (CCC = 0.92), no bias (0.2%), good agreement (±2.5%), and no trend (r = −0.157; p = 0.170) against the DXA. The Bettery® equation is the first to allow for a valid and sport-specific assessment of FM% in male futsal players.

The estimation of body fat percentage (%BF) from anthropometry-related data requires population-specific equations to avoid incorrect interpretations in young athletes. Waist girth (WG) has been described as potential predictor of fat mass (FM) in several populations; however, there are no valid WG-based equations to estimate body composition in young Colombian athletes. The aim of this STandardisierte BerichtsROutine für Sekundärdaten Analysen STROSA-based study was twofold: i) to validate the relative fat mass (RFM) and its pediatric version (RFMp) compared to dual-energy x-ray absorptiometry (DXA) and ii) to develop a new equation (F20CA) to estimate the fat mass in Colombian children and adolescent elite athletes. A total of 114 young athletes that belong to the ‘Team Medellín’ program (58F, 56M; 51 children, 63 adolescents; 14.85 [2.38] years; 55.09 [12.16] kg; 162.38 [11.53] cm) participated in this cross-sectional study. The statistical analysis revealed a poor correlation, agreement and concordance of RFMp and RFM estimations with DXA measurements. After model specification using both Ordinary Least Square method and Bayesian analysis, the regression output revealed that sex, body mass-to-waist ratio, and waist-to-stature ratio were the statistically significant predictor variables that account for variability in FM. The new F20CA equation is expressed as FM (kg) = 5.46 ∗ (Sex) + 0.21 ∗ (BM/W [kg/m]) + 81.7 ∗ (W/Stature [cm/cm]) − 41.8 (R2 = 0.683; SEE = 2.468 kg), where sex is 0 for males and 1 for females. A moderate-to-high correlation and agreement of the F20CA was confirmed within the internal validation data set (R2 = 0.689; ICC [95%CI] = 0.805 [0.615, 0.904]; RMSE = 2.613 kg). The Bland–Altman analysis corroborated the high concordance between the reference method (DXA) and the F20CA-estimated FM (bias [95% LoA] = 1.02 [−3.77, 5.81] kg), indicating the two methods could be considered interchangeable. Even though external validation is needed, practitioners are advised to use the F20CA in young Colombian athletes with similar characteristics to those who participated in this study.

Although dual X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and anthropometry (ANT) are commonly used to evaluate body composition, evidence on their agreement at the segmental level remains limited. This study aimed to compare intra-subject differences in DXA, BIA, and ANT for estimating segmental weight (SW), fat-free mass (FFM), and lean soft mass (LSM) and to examines sex-related influences, and to develop anthropometric prediction equations using DXA as the reference. A cross-sectional study was conducted on 258 young adults (157 males, 101 females). Participants were assessed using DXA, BIA, and ANT. SW, FFM, and LSM were estimated in kilograms and percentages for the upper limbs, trunk, and lower limbs using DXA and BIA. FFM was also estimated using anthropometry (ANT). Significant intra-subject differences were observed between methods across most body segments (  ≤ 0.049), except for SW in the right upper limb (  = 0.328) and LSM in the trunk (  = 0.186) for females. Sex covariable showed a significant influence on the differences found in these comparisons (  ≤ 0.032). Females exhibited lower values of SW, FFM, and LSM in the upper limbs, while males showed higher values of FFM and LSM specifically in the trunk and lower limbs. Bland - Altman analysis revealed a general lack of agreement between DXA and both BIA and ANT, except for BIA when estimating SW in the right upper limb in females (  = 0.167). The new anthropometric equations demonstrated high predictive accuracy (R  > 0.750), with slightly lower values in the upper limbs of females for FFM and LSM (R  = 0.688-0.723). Key predictors included body mass, corrected girths, and segmental lengths. DXA, BIA, and ANT showed significant differences in estimating SW, FFM, and LSM, highlighting their lack of interchangeability. Sex was a significant factor, indicating its importance in body composition estimation. The new anthropometric equations showed good comparability with DXA, although their predictive performance was slightly lower in the upper limbs of females for FFM and LSM.

(1) To develop a new regression equation for estimating fat mass percentage (%FM) from anthropometric measurements in a heterogeneous Caucasian population and (2) to compare it with the Durnin and Womersley equation, which is one of the most used anthropometric equations for FM assessment. Body mass, stature and four skinfolds (biceps, triceps, subscapular and supracrestal) were assessed by an accredited anthropometrist, according to the International Society for Advancement in Kinanthropometry. Participants completed a dual-energy X-ray absorptiometry (DXA) whole-body scan to determine their %FM. A new anthropometric equation to estimate %FM was developed using multiple forward regression analyses with DXA as the reference method. Tests for the accuracy of the different equations included mean differences, coefficient of determination, SE of the estimate (SEE), concordance correlation coefficient (CCC) and Bland-Altman plots. Spain. Two hundred and eighteen healthy Caucasian participants aged 18-65 years participated in this cross-sectional study. Our proposed equation explained 89·9 % of the variance in the DXA-derived %FM, with a low random error (SEE = 3·00 %), a very strong agreement (CCC = 0·93), no fixed or proportional bias and a relatively low individual variability (5·84 %). However, the Durnin and Womersley equations obtained a fixed bias of -3·65 % when compared with DXA and a greater individual variability (6·74 %). The proposed equation can accurately estimate %FM in a heterogeneous Caucasian population with a wide age range (18-65 years). Additionally, the Durnin and Womersley equation was inadequate when applied to our participants.

Objective: To identify associations between physical fitness, extracurricular physical activity, and body adiposity in a representative sample of adolescents from Florianópolis, Brazil. Methods: This cross-sectional, school-based study included 981 adolescents aged 14–18 years attending public schools in Florianópolis, Brazil. The dependent variable was body adiposity, calculated from the sum of triceps and subscapular skinfold thicknesses. Participation in extracurricular physical activity and health-related physical fitness components (flexibility, muscle strength and endurance, cardiorespiratory fitness) were independent variables. Results: The prevalence of high body adiposity was 27.1%, not differing between sexes (boys = 25,0%, girls = 29.4%). There was a negative association between body adiposity, cardiorespiratory fitness, and abdominal endurance in both sexes. The final model explained 58.2% of the variation in body adiposity scores in girls and 47.9% in boys. Negative associations of body adiposity with cardiorespiratory fitness (girls: β = -0.752, p < 0.001; boys: β = -0.655, p < 0.001) and abdominal endurance (girls: β = -0.070, p = 0.021; boys: β = -0.077, p = 0.021) were found in both sexes. Negative associations of body adiposity with extracurricular physical activity were observed in girls (β = -0.078, p = 0.010) and with grip strength (β = -0.121, p < 0.001) and flexibility (β = -0.082, p = 0.015) in boys. Conclusion: Regardless of sex, adolescent groups with low cardiorespiratory fitness and abdominal endurance were the most affected by high body adiposity. Furthermore, lower participation in extracurricular physical activity in girls and lower strength and flexibility in boys were associated with higher body adiposity. Objetivo: Identificar las asociaciones entre aptitud física, actividad física extraescolar y adiposidad corporal en una muestra representativa de adolescentes de Florianópolis, Brasil. Método: estudio transversal, de base escolar, que incluyó a 981 adolescentes de 14 a 18 años, matriculados en escuelas públicas de la ciudad de Florianópolis-SC. La variable dependiente fue la adiposidad corporal, obtenida por la suma de dos pliegues cutáneos (tríceps + subescapular). Se consideraron variables independientes la participación en actividad física extraescolar y los componentes de aptitud física relacionados con la salud (flexibilidad, fuerza y resistencia muscular, aptitud cardiorrespiratoria). Resultados: La prevalencia de adiposidad corporal alta fue de 27,1%, sin diferencia entre sexos (niños= 25%, niñas= 29,4%). Hubo una asociación negativa entre la adiposidad corporal, la aptitud cardiorrespiratoria y la resistencia abdominal en ambos sexos. El modelo final explicó el 58,2% de la variación en los puntajes altos de adiposidad corporal en las niñas y el 47,9% en los niños. En ambos sexos se encontraron asociaciones negativas entre la aptitud cardiorrespiratoria (niñas: β = -0.752, p= <0.001; niños: β = -0.655, p< 0.001) y la resistencia abdominal (niñas: β = -0.070, p= 0.021; niños: β = -0.077, p= 0.021) con adiposidad corporal. Además, en las niñas se observaron asociaciones negativas entre la actividad física extraescolar (β = -0,078, p= 0,010), y en los niños la fuerza de prensión (β = -0,121, p< 0,001) y la flexibilidad (β = -0,082, p =0.015) con adiposidad corporal. Conclusión: En ambos sexos, los niveles más altos de aptitud cardiorrespiratoria y resistencia abdominal se asociaron con la adiposidad de la parte inferior del cuerpo. En las chicas la actividad extraescolar y en los chicos la fuerza y flexibilidad muscular se asociaron negativamente con la adiposidad corporal.