Differences and relationship in functional movement screen (FMS™) scores and physical fitness in males and female semi-professional soccer players.

Background: Soccer is the world's most popular sport for both men and women. Tests of athletic and functional performance are commonly used to assess physical ability and set performance goals. The Functional Movement Screen (FMS™) is a widely used seven-test battery developed by practitioners to provide interpretable measure of movement quality. The main objective of the present study was twofold, to analyze the relationship between FMS™ results from male and female soccer players and to compare their physical performance in different tests. Methods: A total of twenty-eight semi-professional soccer players: fourteen male (age: 21.29 ± 1.64 years; weight: 70.66 ± 5.29 kg; height: 171.86 ± 5.35 cm; BMI: 20.90 ± 2.22 kg/m2) and fourteen females (age: 20.64 ± 1.98 years; weight: 63.44 ± 5.83 kg; height: 166.21 ± 12.18 cm; BMI: 23.02 ± 2.50 kg/m2) were recruited for this study. A paired sample t-test was used for determining differences as a repeated measures analysis. All the participants conducted the following tests: The Functional Movement Test (FMS™), 10-m linear sprint, 5-0-5 COD Test and Yo-Yo Intermittent Recovery Test-Level 1 (YYIRT Level 1). Results: A t-test with data from 505 COD (change of direction) test showed significant differences between groups, p = 0.001, d = 1.11, revealing faster times in male soccer players (2.50 ± 0.19) in respect with female soccer players (2.70 ± 0.17). Crucially, a t-test with data from FMS did not reveal significant differences between groups. Multiple regression for V02max revealed significant effects (r = 0.55, r2 = 0.30, adjusted r2 = 0.24, F = 5.21, p = 0.04 and standard error = 2.20). On the other hand, multiple regression for 10-m sprint showed significant effects (r = 0.58, r2 = 0.33, adjusted r2 = 0.28, F = 5.98, p = 0.03). The impact of these factors on the correlation between FMS™ scores and physical performance measures can vary among individuals. Discussion/Conclusion: This study demonstrates the necessity of utilizing and applying multiple field-based tests to evaluate the movement and capabilities of physical performance in sports. Crucially, consider individual variations and factors such as training background, fitness level, and sport-specific demands when interpreting the relationship between the FMS™ and physical performance in both sexes.

Effects of Different Rapid Weight Loss Strategies and Percentages on Performance-Related Parameters in Combat Sports: An Updated Systematic Review.

Most combat sports (CS) are structured in weight categories, and it is very common to carry out body weight adjustment strategies in order to compete in lower weight categories. For this reason, different rapid weight loss (RWL) strategies are usually performed to pass the pre-competition weigh-in test, and then a replenishment of fluids and carbohydrate-rich foods is conducted in an attempt to recover the weight and avoid a performance loss. In this context, no clear references have been found on whether these types of strategies have negative effects, impairing the athlete's combat and/or physical performance. For this reason, the aim of this study was to review the scientific literature on the effect of rapid weight reduction strategies on the performance of CS athletes. A literature search was performed through four different databases (PubMed, SPORTDiscus, Web of Science and ScienceDirect). Four inclusion criteria were established as follows: (1) the subjects had to be competitors in the CS and carry out RWL strategies; (2) at least two measurement points, that is, normal conditions and dehydration condition; (3) measurements in a real competition or simulating the same conditions; (4) original research articles written in English or Spanish and available in full text. Finally, a total of 16 articles were finally included in this research. All subjects (n = 184) were athletes from combat disciplines, with a minimum of 3-4 years of practice, as well as with certain experience in RWL. Six of the studies reported that an RWL strategy of around 5% of body weight loss did not affect performance parameters. However, the other ten studies with RWL between 3 and 6% or even higher reported negative effects or impairments on different parameters related to performance and/or athlete's psychophysiology, such as perceived fatigue, mood states, strength and power production, as well as changes in hormonal, blood and urine parameters, body composition, or the kinematics of the technical gesture. Although there is still no clear answer to the issue approached in this research, in general terms, it seems that in order to guarantee an acceptable athletic performance of the competitor, the weight loss should not exceed 3% to ≤5% of body weight together with ≥24 h for adequate (or at least partial) recovery and rehydration processes. In addition, it is highly recommended to lose weight progressively over several weeks, especially focusing on competitions lasting several days, as well as multiple rounds or qualifying stages.

Effects of 10-Week Online Moderate- to High-Intensity Interval Training on Body Composition, and Aerobic and Anaerobic Performance during the COVID-19 Lockdown.

The present study aimed to investigate the effects of a 10-week online high-intensity interval training (HIIT) program on body composition and aerobic and aerobic performance in physically sedentary women. A parallel, two-group, longitudinal (pre, post) design was used with physical tests performed before (preintervention) and after (postintervention) the 10-week intervention period. A total of forty-eight healthy and physically sedentary women (defined as an individual who lacks regular exercise or a structured fitness routine) were recruited to participate in this study. The participants were distributed in two groups: the experimental group (EG) with 24 women (mean ± SD: age 21.21 ± 2.15 years; weight: 61.16 ± 8.94 kg; height: 163.96 ± 4.87 cm; body mass index (BMI): 22.69 ± 2.49 kg/m2) and the control group (CG) with another 24 women (mean ± SD: age 20.50 ± 1.29 years; weight: 62.0 ± 6.65 kg; height: 163.92 ± 4.89 cm; body mass index: 23.04 ± 1.74 kg/m2). The EG performed an online HIIT program for 10 weeks, while the CG continued with their daily life routines. The repeated measures ANCOVA indicated a significant effect in the within-group analysis for weight (p = 0.001; d = -0.96) and for BMI (p = 0.001; d = 0.24), with a significant decrease in the experimental group (EG). The control group (CG) did not show any significant decrease in either body weight or BMI. Regarding the maximal oxygen uptake (VO2 max) values, the EG exhibited a significant improvement (p = 0.001; d = -1.07), whereas the CG did not demonstrate a significant improvement (p = 0.08; d = -0.37). The EG's power output (W) (p = 0.001; d = -0.50) and power output standardized by body weight (W/kg) (p = 0.001; d = -0.96) were significantly improved. The CG did not show a significant improvement in either power output (W/kg) or power output. Lastly, the within-group analysis with load revealed that the EG significantly improved (p = 0.001; d = -0.50), while CG did not show a significant improvement in load (p = 0.10.; d = -0.10). The present study showed that 10 weeks of HIIT in an online environment during the COVID-19 lockdown significantly improved maximum oxygen consumption and caused weight loss and a significant decrease in body mass index in physically sedentary women. These results suggest that HIIT may be used as a time-efficient strategy to improve body composition and cardio-respiratory fitness in sedentary women.

Juegos tradicionales para niños con discapacidad visual: un conocimiento necesario en educación médica / Traditional games for visually impaired children: a necessary knowledge in medical education

Fundamento: los juegos tradicionales resultan motivantes y de fácil ejecución para los escolares con necesidades educativas especiales porque favorecen la movilidad y orientación espacial de niños con discapacidad visual. Objetivo: proponer un grupo de juegos tradicionales adaptados para mejorar la movilidad y orientación espacial de niños con discapacidad visual en la Escuela Especial "Fructuoso Rodríguez" de Santa Clara, Villa Clara, Cuba. Métodos: se realizó un estudio descriptivo transversal, entre los meses de mayo-septiembre de 2021. Se emplearon métodos teóricos: analítico-sintético, inductivo-deductivo e histórico-lógico; y empíricos: análisis de documentos, observación, cuestionario y entrevista. Resultados: el diagnóstico realizado corroboró que los sujetos estudiados presentaban dificultades en la movilidad y la orientación espacial; desconfianza, inseguridad y pocas iniciativas relacionadas con la recreación en su cotidianeidad familiar, por lo que se adaptaron 10 juegos tradicionales conocidos, pero poco jugados por los niños con discapacidad visual, con el fin de alcanzar otras vías que contribuyan a mejorar su movilidad y orientación espacial, luego de una etapa de confinamiento provocada por la Covid-19. Conclusiones: la propuesta de juegos tradicionales adaptados responde a la necesidad detectada y potencia la recreación e inclusión de estos infantes en actividades escolares y extraescolares después de la pandemia.

Background: traditional games are motivating and easy to play for schoolchildren with special educational needs because they favor the mobility and spatial orientation of visually impaired children. Objective: to propose a group of traditional games adapted to improve the mobility and spatial orientation of visually impaired children at "Fructuoso Rodríguez" Special School in Santa Clara, Villa Clara, Cuba. Methods: a cross-sectional descriptive study was carried out, from May to September 2021. Theoretical methods were used: analytical-synthetic, inductive-deductive and historical-logical; and empirical ones: document analysis, observation, questionnaire and interview. Results: the diagnosis made corroborated that the subjects studied presented difficulties in mobility and spatial orientation; distrust, insecurity and few initiatives related to recreation in their family daily life, for which 10 known traditional games were adapted, but little played by children with visual disabilities, in order to reach other ways that contribute to improving their mobility and orientation space, after a stage of confinement caused by Covid-19. Conclusions: the proposal of adapted traditional games responds to the detected need and enhances the recreation and inclusion of these infants in school and extracurricular activities after the pandemic.

A Data Analytics Approach to Assess the Functional and Physical Performance of Female Soccer Players: A Cohort Design.

BACKGROUND AND OBJECTIVES: The aim of this study was twofold: (i) to observe the individual results of fitness status [countermovement jump (CMJ)], hop test, linear sprinting time, stride frequency, stride distance, force-power-velocity, peak power maximal and maximal speed, and repeated sprint ability (RSA) and functional performance (overhead squat, single-leg squat test, dumbbell hip-hinge, Thomas test, hip extension, and internal and external hip rotators) and (ii) to analyze the relationship between anthropometrical measures and values of fitness status with % of difference in the Thomas test, hip extension, and internal and external hip rotators. MATERIALS AND METHODS: The study followed a cohort design. Sixteen female soccer players competing in the second division of the Spanish league were monitored during the first days of the pre-season. These players were evaluated three times during the preseason of the cohort period. The dataset showed a negative moderate correlation between time and percentage of difference in hip angle and another positive moderate correlation between maximal sprint and percentage of difference in hip angle (r = -0.54, p = 0.02 and r = 0.53, p = 0.04), respectively. The correlations of stride time and distance with hip extension are interesting, as professional soccer players should have higher levels of hip flexor flexibility during the stride phase, recoil of the instep kick action.

Effects of Power Training on Physical Activity, Sitting Time, Disability, and Quality of Life in Older Patients With Type 2 Diabetes During the COVID-19 Confinement.

BACKGROUND: To evaluate the effectiveness of a multicomponent supervised and unsupervised training program focused on muscle power to counteract the potential changes in sedentary behavior, disability, physical activity (PA), and health-related quality of life (HRQoL) caused by the COVID-19 pandemic domiciliary confinement in prefrail older adults with type 2 diabetes mellitus. METHODS: Thirty-five older adults with type 2 diabetes mellitus were assigned to 2 groups according to their frailty status: exercise training group (prefrail or frail; n = 21; 74.7 [4.5] y; 33.3% male) and control group (robust; n = 14; 73.1 [3.9] y; 42.9% male). The exercise training group followed a multicomponent training program focusing on muscle power: supervised (5 wk) and unsupervised (6 wk). The primary outcomes, including PA and sitting time, perceived disability, and HRQoL, were assessed at the baseline and after 11 weeks. RESULTS: At the end of confinement, there were significant decreases in PA in both groups (P < .05). Thus, sitting time increased more in the control group than in the exercise training group (P < .05). The HRQoL measures remained unchanged. CONCLUSIONS: Muscle power training before and during mandatory COVID-19 self-isolation in type 2 diabetes mellitus older adults (1) attenuates the COVID-19 domiciliary confinement-related increase in sitting time and (2) slightly decreases the self-reported levels of disability and maintains HRQoL.

Androgen receptor gene polymorphisms and maximal fat oxidation in healthy men. A longitudinal study.

INTRODUCTION: Androgens play a major role in fat oxidation; however, the effects of androgens depend, among other factors, on the intrinsic characteristics of the androgen receptor (AR). Lower repetitions of CAG and GGN polymorphism appear to have a protective effect on fat accumulation in the transition from adolescent to mid-twenties. Whether a similar protective effect is present later in life remains unknown. The aims of this study were: a) to evaluate if extreme CAG and GGN repeat polymorphisms of the androgen receptors influence body fat mass, its regional distribution, resting metabolic rate (RMR), maximal fat oxidation capacity (MFO) and serum leptin, free testosterone and osteocalcin in healthy adult men; and b) to determine the longitudinal effects on fat tissue accumulation after 6.4 years of follow-up. METHODS: CAG and GGN repeats length were measured in 319 healthy men (mean ± standard deviation [SD]: 28.3 ± 7.6 years). From these, we selected the subjects with extreme short (CAGS < or equal 19; n = 7) and long (CAGL > or equal 24; n = 10) CAG repeats, and the subjects with short (GGNS < or equal to 22; n = 9) and long (GGNL > or equal to 25; n = 10) GGN repeats. Body composition was assessed by DXA and serum levels of leptin, free testosterone and osteocalcin by ELISA. After 6.4 years of follow-up, DXA was repeated, and resting metabolic rate (RMR), MFO and VO2max determined by indirect calorimetry. RESULTS: CAGS and CAGL subjects had similar RMR and accumulated comparable amounts of fat tissue over 6.4 ± 1.0 years of follow-up. However, CAGL had higher MFO and total lean mass than CAGS (p < 0.05). Men with GGNS accumulated greater amount of total fat mass than men with GGNL, particularly in the trunk region seven years later. This concurred with a greater MFO in the GGNL group (p < 0.05), who accumulated less fat mass. Free testosterone was associated with MFO in absolute values (r = 0.45; p < 0.05) and MFO per kg of lower extremity lean mass per height squared (r = 0.35; p < 0.05). CONCLUSIONES: CAG and GGN repeat polymorphisms may influence muscle fat oxidation capacity and may have a role in the accumulation of fat over the years.

Androgen receptor gene polymorphisms and maximal fat oxidation in healthy men. A longitudinal study / Polimorfismo del gen del receptor de andrógenos y oxidación máxima de grasa en hombres sanos. Estudio longitudinal

Introduction: Androgens play a major role in fat oxidation; however, the effects of androgens depend, among other factors, on the intrinsic characteristics of the androgen receptor (AR). Lower repetitions of CAG and GGN polymorphism appear to have a protective effect on fat accumulation in the transition from adolescent to mid-twenties. Whether a similar protective effect is present later in life remains unknown. The aims of this study were: a) to evaluate if extreme CAG and GGN repeat polymorphisms of the androgen receptors influence body fat mass, its regional distribution, resting metabolic rate (RMR), maximal fat oxidation capacity (MFO) and serum leptin, free testosterone and osteocalcin in healthy adult men; and b) to determine the longitudinal effects on fat tissue accumulation after 6.4 years of follow-up. Methods: CAG and GGN repeats length were measured in 319 healthy men (mean ± standard deviation [SD]: 28.3 ± 7.6 years). From these, we selected the subjects with extreme short (CAGS ≤ 19; n = 7) and long (CAGL ≥ 24; n = 10) CAG repeats, and the subjects with short (GGNS ≤ 22; n = 9) and long (GGNL ≥ 25; n = 10) GGN repeats. Body composition was assessed by DXA and serum levels of leptin, free testosterone and osteocalcin by ELISA. After 6.4 years of follow-up, DXA was repeated, and resting metabolic rate (RMR), MFO and VO2max determined by indirect calorimetry. Results: CAGS and CAGL subjects had similar RMR and accumulated comparable amounts of fat tissue over 6.4 ± 1.0 years of follow-up. However, CAGL had higher MFO and total lean mass than CAGS (p < 0.05). Men with GGNS accumulated greater amount of total fat mass than men with GGNL, particularly in the trunk region seven years later. This concurred with a greater MFO in the GGNL group (p < 0.05), who accumulated less fat mass. Free testosterone was associated with MFO in absolute values (r = 0.45; p < 0.05) and MFO per kg of lower extremity lean mass per height squared (r = 0.35; p < 0.05). Conclusions: CAG and GGN repeat polymorphisms may influence muscle fat oxidation capacity and may have a role in the accumulation of fat over the years (AU)

Introducción: los andrógenos juegan un papel importante en la oxidación de grasas; sin embargo, el efecto de los andrógenos depende, entre otros factores, de las características intrínsecas del receptor de andrógenos (RA). Un menor número de repeticiones CAG y GGN del RA parecen tener un efecto protector sobre la acumulación de grasa en la transición de la adolescencia hasta la veintena. Se desconoce si adelante en la vida persiste un efecto protector similar. Los objetivos de este estudio fueron: a) evaluar si repeticiones extremas de los polimorfismos CAG y GGN del RA influyen sobre la masa grasa corporal, su distribución regional, la tasa metabólica en reposo (RMR), la máxima oxidación de grasas (MFO) y la concentración sérica de leptina, testosterona libre y osteocalcina en hombres sanos; y b) determinar los efectos longitudinales sobre la acumulación de grasa después de 6.4 años de seguimiento. Métodos: la longitud de las repeticiones de CAG y GGN fueron medidas en 319 hombres sanos (media ± desviación estándar [SD]: 28,3 ± 7,6 años). De estos, seleccionamos los sujetos con repeticiones del CAG extremas cortas (CAGS ≤ 19; n = 7) y largas (CAGL ≥ 24; n = 10), y los sujetos con repeticiones del GGN extremas cortas (GGNS ≤ 22; n = 9) y largas (GGNL ≥ 25; n = 10). Se evaluaron la composición corporal mediante DXA y los niveles séricos de leptina, testosterona libre y osteocalcina por ELISA. Tras 6.4 años de seguimiento el DXA fue repetido, y la tasa metabólica en reposo (RMR), máxima oxidación de grasas (MFO) y VO2max fueron determinados mediante calorimetría indirecta. Resultados: los grupos CAGS y CAGL fueron comparables en RMR y cantidad de tejido graso tras 6,4 ± 1,0 años de seguimiento. Sin embargo, el grupo CAGL tuvo mayor MFO y masa libre de grasa que el grupo CAGS (p < 0,05). Los hombres con GGNS acumularon mayor cantidad de masa grasa total que los hombres con GGNL, particularmente en la región del tronco siete años después. Esto concordó con un mayor MFO en el grupo GGNL (p < 0,05), que acumuló menos masa grasa. La testosterona libre se asoció con el MFO en valores absolutos (r = 0,45; p < 0,05) y con MFO expresado por kg de masa libre de grasa de las piernas al cuadrado (r = 0,35; p < 0,05). Conclusiones: las repeticiones del polimorfismo del CAG y GGN pueden influenciar la capacidad muscular de oxidación de grasas y pueden tener un rol en la acumulación de grasa con los años (AU)

Androgen receptor CAG and GGN repeat polymorphisms influence performance in boys and girls.

BACKGROUND: Shorter CAG and GGN androgen receptor (AR) repeat polymorphisms are associated with stronger androgen signaling, and therefore, could influence lean mass and exercise performance during growth. METHODS: Physical fitness and body composition were measured by standardized procedures and the length of CAG and GGN repeats was determined by PCR and fragment analysis in 152 boys (11.5±2.6 years; Tanner ≤5) and 116 girls (10.1±3.2 years; Tanner ≤5). Individuals were grouped as CAG short (CAGS) if harboring repeat lengths of ≤21 and CAG long (CAGL) if CAG >21. Moreover, subjects were grouped as GGN short (GGNS) if harboring repeat lengths of ≤23 and GGN long (GGNL) if GGN>23. RESULTS: No significant differences in anthropometrics and body composition were observed between either CAGS and CAGL groups and GGNS and GGNL groups. Boys harboring CAGS completed the 300-meter test faster than their CAGL counterparts. Moreover, girls from the GGNL group showed a significant higher VO2max than those in the GGNS group. CONCLUSIONS: In summary, carrying a short allele of the androgen receptor CAG repeat polymorphism is associated to higher anaerobic performance in boys, whereas long alleles of androgen receptor GGN polymorphisms are associated to higher aerobic capacity in girls.

Greater basal skeletal muscle AMPKα phosphorylation in men than in women: Associations with anaerobic performance.

OBJECTIVES: This study was designed to investigate the association of gender, fibre type composition, and anaerobic performance with the basal skeletal muscle signalling cascades regulating muscle phenotype. DESIGN: Muscle biopsies were obtained from 25 men and 10 women all young and healthy. METHODS: Protein phosphorylation of Thr(172)AMPKα, Ser(221)ACCß, Thr(286)CaMKII as well as total protein abundance of PGC-1α, SIRT1, and CnA were measured by Western blot and anaerobic performance by the Wingate test. RESULTS: Percent type I myosin heavy chain (MHC I) was lower in men (37.1 ± 10.4 vs. 58.5 ± 12.5, P < .01). Total, free testosterone and free androgen index were higher in men (11.5, 36.6 and 40.6 fold, respectively, P < .01). AMPKα phosphorylation was 2.2-fold higher in men compared to women (P < .01). Total Ser(221)ACCß and Thr(286)CaMKII fractional phosphorylation tended to be higher in men (P = .1). PGC1-α and SIRT1 total protein expression was similar in men and women, whereas CnA tended to be higher in men (P = .1). Basal AMPKα phosphorylation was linearly related to the percentage of MHC I in men (r = 0.56; P < .01), but not in women. No association was observed between anaerobic performance and basal phosphorylations in men and women, analysed separately. CONCLUSION: In summary, skeletal muscle basal AMPKα phosphorylation is higher in men compared to women, with no apparent effect on anaerobic performance.

ANDROGEN RECEPTOR CAG AND GGN REPEAT POLYMORPHISMS AND BONE MASS IN BOYS AND GIRLS.

INTRODUCTION: the human androgen receptor (AR) gene possesses two trinucleotide polymorphic repeats, (CAG and GGN) that affect the amount of AR protein translated. In this study, we genotyped these polymorphic tracts in a representative sample of Caucasian children (Tanner ≤ 5), 152 boys (11.5 } 2.6 yrs) and 116 girls (10.1 } 3.2 yrs) from Spain and investigated their association with bone mass. METHODS: the length of CAG and GGN repeats was determined by PCR and fragment analysis. Body composition was assessed by dual energy x-ray absorptiometry (DXA). Individuals were grouped as CAG short (CAGS) if harboring repeat lengths of ≤ 21 and CAG long (CAGL) if CAG > 21. Moreover, subjects were grouped as GGN short (GGNS) if harboring repeat lengths of ≤ 23 and GGN long (GGNL) if GGN > 23. RESULTS: in boys, significant differences in height, body mass, whole body bone mineral density (BMD) and content (BMC), upper extremities BMC, lower extremities BMC, femoral neck BMD, Ward's triangle BMC and BMD and lumbar spine BMD were observed between CAGS and CAGL groups (P < 0.05). Thus, upper extremities BMD differed between GGNS and GGNL groups. After adjusting for confounding variables, only upper extremities BMD between GGNS and GGNL groups remained significant (P < 0.05). No differences were observed in girls in any measured site in relation to either CAG or GGN polymorphisms length. CONCLUSIONS: our results support the hypothesis that longer alleles of the AR CAG and GGN polymorphisms are associated with increased bone mass in prepubertal boys.

Introducción: el gen humano del receptor de androgenos (AR) posee dos repeticiones polimorficas de trinucleotidos (CAG y GGN) que afectan a la cantidad de proteina AR traducida. En este estudio, genotipamos esos tractos polimorficos en una muestra representativa de ninos caucasicos espanoles (Tanner ≤ 5), compuesta por 152 ninos (11.5 } 2.6 anos) y 116 ninas (10.1 } 3.2 anos) e investigamos su asociacion con la masa osea. Métodos: la longitud de las repeticiones CAG y GGN se determino mediante PCR y analisis de fragmentos. La composicion corporal se midio mediante absorciometria dual de rayos X (DXA). Los participantes fueron agrupados como CAG cortos (CAGS) si poseian una longitud de repeticiones ≤ 21 y CAG largos si esta era > 21. Ademas, los participantes se agruparon como GGN cortos (GGNS) si poseian una longitud de repeticiones ≤ 23 y GGN largos (GGNL) si esta era > 23. Resultados: en los ninos se encontraron diferencias en talla, peso corporal, densidad mineral osea (BMD) y contenido mineral oseo (BMC) del cuerpo entero, BMC de las extremidades superiores e inferiores, BMD del cuello del femur, BMC y BMD del triangulo de Ward's y BMD de la espina lumbar entre los grupos CAGS y CAGL (P < 0,05). Ademas, el BMD de las extremidades superiores fue significativamente diferente entre los grupos GGNS y GGNL. Tras ajustar por variables confusoras, la unica diferencia que se mantuvo significativa fue la del BMD en las extremidades superiores entre los grupos GGNS y GGNL (P < 0,05). No se observaron diferencias entre los grupos CAG y GGN y la masa osea en las ninas. Conclusiones: nuestros resultados apoyan la hipotesis de que los alelos largos de los polimorfismos CAG y GGN del AR estan asociados con una mayor masa osea en ninos prepuberes.

Androgen receptor CAG and GGN repeat polymorphisms and bone mass in boys and girls / Polimorfismos CAG y GGN del gen del receptor de andrógenos y masa ósea en niños y niñas

Introduction: the human androgen receptor (AR) gene possesses two trinucleotide polymorphic repeats, (CAG and GGN) that affect the amount of AR protein translated. In this study, we genotyped these polymorphic tracts in a representative sample of Caucasian children (Tanner ≤5), 152 boys (11.5±2.6 yrs) and 116 girls (10.1±3.2 yrs) from Spain and investigated their association with bone mass. Methods: the length of CAG and GGN repeats was determined by PCR and fragment analysis. Body composition was assessed by dual energy x-ray absorptiometry (DXA). Individuals were grouped as CAG short (CAGS) if harboring repeat lengths of ≤21 and CAG long (CAGL) if CAG >21. Moreover, subjects were grouped as GGN short (GGNS) if harboring repeat lengths of ≤23 and GGN long (GGNL) if GGN >23. Results: in boys, significant differences in height, body mass, whole body bone mineral density (BMD) and content (BMC), upper extremities BMC, lower extremities BMC, femoral neck BMD, Ward’s triangle BMC and BMD and lumbar spine BMD were observed between CAGS and CAGL groups (P<0.05). Thus, upper extremities BMD differed between GGNS and GGNL groups. After adjusting for confounding variables, only upper extremities BMD between GGNS and GGNL groups remained significant (P<0.05). No differences were observed in girls in any measured site in relation to either CAG or GGN polymorphisms length. Conclusions: our results support the hypothesis that longer alleles of the AR CAG and GGN polymorphisms are associated with increased bone mass in prepubertal boys (AU)

Introducción: el gen humano del receptor de andrógenos (AR) posee dos repeticiones polimórficas de trinucleótidos (CAG y GGN) que afectan a la cantidad de proteína AR traducida. En este estudio, genotipamos esos tractos polimórficos en una muestra representativa de niños caucásicos españoles (Tanner ≤5), compuesta por 152 niños (11.5±2.6 años) y 116 niñas (10.1±3.2 años) e investigamos su asociación con la masa ósea. Métodos: la longitud de las repeticiones CAG y GGN se determinó mediante PCR y análisis de fragmentos. La composición corporal se midió mediante absorciometría dual de rayos X (DXA). Los participantes fueron agrupados como CAG cortos (CAGS) si poseían una longitud de repeticiones ≤21 y CAG largos si esta era >21. Además, los participantes se agruparon como GGN cortos (GGNS) si poseían una longitud de repeticiones ≤23 y GGN largos (GGNL) si esta era >23. Resultados: en los niños se encontraron diferencias en talla, peso corporal, densidad mineral ósea (BMD) y contenido mineral óseo (BMC) del cuerpo entero, BMC de las extremidades superiores e inferiores, BMD del cuello del fémur, BMC y BMD del triángulo de Ward’s y BMD de la espina lumbar entre los grupos CAGS y CAGL (P<0,05). Además, el BMD de las extremidades superiores fue significativamente diferente entre los grupos GGNS y GGNL. Tras ajustar por variables confusoras, la única diferencia que se mantuvo significativa fue la del BMD en las extremidades superiores entre los grupos GGNS y GGNL (P<0,05). No se observaron diferencias entre los grupos CAG y GGN y la masa ósea en las niñas. Conclusiones: nuestros resultados apoyan la hipótesis de que los alelos largos de los polimorfismos CAG y GGN del AR están asociados con una mayor masa ósea en niños prepúberes (AU)

Limitations to oxygen transport and utilization during sprint exercise in humans: evidence for a functional reserve in muscle O2 diffusing capacity.

To determine the contribution of convective and diffusive limitations to V̇(O2peak) during exercise in humans, oxygen transport and haemodynamics were measured in 11 men (22 ± 2 years) during incremental (IE) and 30 s all-out cycling sprints (Wingate test, WgT), in normoxia (Nx, P(IO2): 143 mmHg) and hypoxia (Hyp, P(IO2): 73 mmHg). Carboxyhaemoglobin (COHb) was increased to 6-7% before both WgTs to left-shift the oxyhaemoglobin dissociation curve. Leg V̇(O2) was measured by the Fick method and leg blood flow (BF) with thermodilution, and muscle O2 diffusing capacity (D(MO2)) was calculated. In the WgT mean power output, leg BF, leg O2 delivery and leg V̇(O2) were 7, 5, 28 and 23% lower in Hyp than Nx (P < 0.05); however, peak WgT D(MO2) was higher in Hyp (51.5 ± 9.7) than Nx (20.5 ± 3.0 ml min(-1) mmHg(-1), P < 0.05). Despite a similar P(aO2) (33.3 ± 2.4 and 34.1 ± 3.3 mmHg), mean capillary P(O2) (16.7 ± 1.2 and 17.1 ± 1.6 mmHg), and peak perfusion during IE and WgT in Hyp, D(MO2) and leg V̇(O2) were 12 and 14% higher, respectively, during WgT than IE in Hyp (both P < 0.05). D(MO2) was insensitive to COHb (COHb: 0.7 vs. 7%, in IE Hyp and WgT Hyp). At exhaustion, the Y equilibration index was well above 1.0 in both conditions, reflecting greater convective than diffusive limitation to the O2 transfer in both Nx and Hyp. In conclusion, muscle V̇(O2) during sprint exercise is not limited by O2 delivery, O2 offloading from haemoglobin or structure-dependent diffusion constraints in the skeletal muscle. These findings reveal a remarkable functional reserve in muscle O2 diffusing capacity.

Critical role for free radicals on sprint exercise-induced CaMKII and AMPKα phosphorylation in human skeletal muscle.

The extremely high energy demand elicited by sprint exercise is satisfied by an increase in O2 consumption combined with a high glycolytic rate, leading to a marked lactate accumulation, increased AMP-to-ATP ratio, and reduced NAD(+)/NADH.H(+) and muscle pH, which are accompanied by marked Thr(172) AMP-activated protein kinase (AMPK)-α phosphorylation during the recovery period by a mechanism not fully understood. To determine the role played by reactive nitrogen and oxygen species (RNOS) on Thr(172)-AMPKα phosphorylation in response to cycling sprint exercise, nine voluntary participants performed a single 30-s sprint (Wingate test) on two occasions: one 2 h after the ingestion of placebo and another after the intake of antioxidants (α-lipoic acid, vitamin C, and vitamin E) in a double-blind design. Vastus lateralis muscle biopsies were obtained before, immediately postsprint, and 30 and 120 min postsprint. Performance and muscle metabolism were similar during both sprints. The NAD(+)-to-NADH.H(+) ratio was similarly reduced (84%) and the AMP-to-ATP ratio was similarly increased (×21-fold) immediately after the sprints. Thr(286) Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and Thr(172)-AMPKα phosphorylations were increased after the control sprint (with placebo) but not when the sprints were preceded by the ingestion of antioxidants. Ser(485)-AMPKα1/Ser(491)-AMPKα2 phosphorylation, a known inhibitory mechanism of Thr(172)-AMPKα phosphorylation, was increased only with antioxidant ingestion. In conclusion, RNOS play a crucial role in AMPK-mediated signaling after sprint exercise in human skeletal muscle. Antioxidant ingestion 2 h before sprint exercise abrogates the Thr(172)-AMPKα phosphorylation response observed after the ingestion of placebo by reducing CaMKII and increasing Ser(485)-AMPKα1/Ser(491)-AMPKα2 phosphorylation. Sprint performance, muscle metabolism, and AMP-to-ATP and NAD(+)-to-NADH.H(+) ratios are not affected by the acute ingestion of antioxidants.

Increased oxidative stress and anaerobic energy release, but blunted Thr172-AMPKα phosphorylation, in response to sprint exercise in severe acute hypoxia in humans.

AMP-activated protein kinase (AMPK) is a major mediator of the exercise response and a molecular target to improve insulin sensitivity. To determine if the anaerobic component of the exercise response, which is exaggerated when sprint is performed in severe acute hypoxia, influences sprint exercise-elicited Thr(172)-AMPKα phosphorylation, 10 volunteers performed a single 30-s sprint (Wingate test) in normoxia and in severe acute hypoxia (inspired Po(2): 75 mmHg). Vastus lateralis muscle biopsies were obtained before and immediately after 30 and 120 min postsprint. Mean power output and O(2) consumption were 6% and 37%, respectively, lower in hypoxia than in normoxia. O(2) deficit and muscle lactate accumulation were greater in hypoxia than in normoxia. Carbonylated skeletal muscle and plasma proteins were increased after the sprint in hypoxia. Thr(172)-AMPKα phosphorylation was increased by 3.1-fold 30 min after the sprint in normoxia. This effect was prevented by hypoxia. The NAD(+)-to-NADH.H(+) ratio was reduced (by 24-fold) after the sprints, with a greater reduction in hypoxia than in normoxia (P < 0.05), concomitant with 53% lower sirtuin 1 (SIRT1) protein levels after the sprint in hypoxia (P < 0.05). This could have led to lower liver kinase B1 (LKB1) activation by SIRT1 and, hence, blunted Thr(172)-AMPKα phosphorylation. Ser(485)-AMPKα(1)/Ser(491)-AMPKα(2) phosphorylation, a known negative regulating mechanism of Thr(172)-AMPKα phosphorylation, was increased by 60% immediately after the sprint in hypoxia, coincident with increased Thr(308)-Akt phosphorylation. Collectively, our results indicate that the signaling response to sprint exercise in human skeletal muscle is altered in severe acute hypoxia, which abrogated Thr(172)-AMPKα phosphorylation, likely due to lower LKB1 activation by SIRT1.

Skeletal muscle signaling response to sprint exercise in men and women.

To determine if there is a sex dimorphism in the skeletal muscle signaling response to sprint exercise, 17 men and ten women performed a 30-s Wingate test. Muscle biopsies were taken before, immediately after the exercise and at 30 and 120 min during the recovery period. Thr(172)-AMPKα, Ser(221)-ACCß, Thy(705)-STAT3, Thr(202)/Thy(204)-ERK1/2 and Thr(180)/Thy(182)-p38MAPK phosphorylation responses to sprint exercise were not statistically different between men and women. AMPKα phosphorylation was enhanced fourfold 30 min after the sprint exercise in males and females (P < 0.01). ACCß phosphorylation was enhanced by about threefold just after the sprint test exercise and 30 min into the recovery period in males and females (P < 0.01). STAT3 phosphorylation was increased 2 h after the Wingate test compared to the value observed right after the end of the exercise (P < 0.05), and 30 min after the Wingate test there was a 2.5-fold increase in ERK1/2 phosphorylation, compared to both the pre-exercise and to the value observed right after the Wingate test (both, P < 0.05). In conclusion, the skeletal muscle signaling response to a single bout of sprint exercise mediated by AMPK, ACC, STAT3, ERK and p38MAPK is not statistically different between men and women. Marked increases in AMPKα, ACCß, STAT3 and ERK phosphorylation were observed after a single 30-s all-out sprint (Wingate test) in the vastus lateralis.

Androgen receptor gene polymorphisms and the fat-bone axis in young men and women.

Androgen receptor (AR) CAG(n) (polyglutamine) and GGN(n) (polyglycine) repeat polymorphisms determine part of the androgenic effect and may influence adiposity. The association of fat mass, and its regional distribution, with the AR CAG(n) and GGN(n) polymorphisms was studied in 319 and 78 physically active nonsmoker men and women (mean ± SD: 28.3 ± 7.6 and 24.8 ± 6.2 years old, respectively). The length of CAG and GGN repeats was determined by polymerase chain reaction and fragment analysis, and confirmed by DNA sequencing of selected samples. Men were grouped as CAG short (CAG(S)) if harboring repeat lengths ≤ 21, the rest as CAG long (CAG(L)). The corresponding cutoff CAG number for women was 22. GGN was considered short (GGN(S)) if GGN ≤ 23, the rest as GGN long (GGN(L)). No association between AR polymorphisms and adiposity or the hormonal variables was observed in men. Neither was there a difference in the studied variables between men harboring CAG(L) + GGN(L),CAG(S) + GGN(S),CAG(S) + GGN(L), and CAG(L) + GGN(S) combinations. However, in women, GGN(n) was linearly related to the percentage of body fat (r = 0.30, P < .05), the percentage of fat in the trunk (r = 0.28, P < .05), serum leptin concentration (r = 0.40, P < .05), and serum osteocalcin concentration (r = 0.32, P < .05). In men, free testosterone was inversely associated with adiposity and serum leptin concentration, and positively with osteocalcin, even after accounting for differences in CAG(n), GGN(n), or both. In summary, this study shows that the AR repeat polymorphism has little influence on absolute and relative fat mass or its regional distribution in physically active men. In young women, GGN length is positively associated with adiposity, leptin, and osteocalcin.