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Monitoring of changes in skeletal muscle oxygenation during exercise has increased in recent years. Tissue oxygenation, which is related to fatigue and muscle hypertrophy, is often measured using near-infrared spectroscopy (NIRS)., Objectives: This study aimed to determine the test-retest reliability of a non-portable NIRS (NIRO200Nx) during the full-squat exercise and recovery in young healthy men., Design: Twenty-five male participants (21.8 ± 2.6 years) were recruited for this original research. Each participant completed an 8-repetition test with a load that elicited a velocity of 1 m·s -1 . The test was conducted twice, with a 48-hour washout period between sessions., Methods: The NIRS measured the changes of oxygenated-Hemoglobin (O 2 Hb), deoxygenated-Hemoglobin (HHb) and Tissue Oxygenation Index (TOI) in both Vastus Lateralis and Vastus Medialis during rest, exercise, and recovery. Coefficient of Variation (CV), Standard Error Measurement (SEM) and Intraclass Correlation Coefficient (ICC) were used to evaluate the reliability of the data. Significance was set at p < 0.05., Results: The results indicated that TOI had good to acceptable absolute reliability (CV TOI  = 2.7-10.2 %). A good relative relativity for the overall test was found for Vastus Medialis O 2 Hb (ICC = 0.851), HHb (ICC = 0.852), and TOI (ICC = 0.864), and Vastus Lateralis O 2 Hb (ICC = 0.898), HHb (ICC = 0.899), and TOI (ICC = 0.897)., Conclusions: We conclude that NIRO200Nx is a reliable instrument for measuring muscle oxygen saturation through the TOI parameter in not-to-failure dynamic resistance exercises (1 set of 8 reps against ∼40 % 1 repetition maximum). Tissue oxygenation assessment could be a new way of individualizing exercise through dynamic resistance exercises., Competing Interests: Declaration of interest statement The authors report that there are no competing interests to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The role of polymorphism rs9939609 of the FTO gene has been related with fat mass and cardiovascular risk in adults, but it remains unclear in children and adolescents. Hence, the main aim of this study was to determine the FTO polymorphism effects on body composition, cardiorespiratory fitness (CRF), physical activity (PA), inflammatory markers, and cardiovascular risk both in cross-sectional analysis and after two-years of follow-up in children and adolescents. A total of 2129 participants were included in this study. The rs9939609 polymorphism was genotyped. Body composition measurements, CRF, and moderate-to-vigorous PA (MVPA) were determined at baseline and after two-year of follow-up. Moreover, plasma leptin and adiponectin were also determined as inflammatory markers. Furthermore, an index of cardiovascular disease risk factors (CVDRF-I) was calculated. Codominant (TT vs. TA vs. AA) and dominant (AA+AT vs. TT) models were applied for statistical analysis. The results showed a main effect of the FTO genotype on body composition measures in both first and third year (p < 0.05), with lower adiposity in TT compared with AA or AA+AT group. These differences were maintained after accounting for pubertal maturity, sex, age, VO 2 max, and MVPA. Moreover, lower leptin level was observed in TT compared to AA+AT group in the third year. An interaction in Gene*Time*Sex was found in height and neck circumference in dominant model (p = 0.047; p = 0.020, respectively). No differences were found in CRF, MVPA nor CVDRF-I between groups. Hence, homozygous TT allele could be a protective factor against weight gain from early childhood., (© 2023 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Abstract: Costilla, M, Casals, C, Marín-Galindo, A, Sánchez-Sixto, A, Muñoz-López, A, Sañudo, B, Corral-Pérez, J, and Ponce-González, JG. Changes in muscle deoxygenation during squat exercise after 6-week resistance training with different percentages of velocity loss. J Strength Cond Res 37(8): 1573-1580, 2023-The present study compared, for the first time, the effects of 6 weeks of 20% (20VL) vs. 40% (40VL) velocity loss (VL) resistance training (RT) programs on muscle oxygen dynamics during the squat exercise. Twenty-three young men (21.4 ± 2.4 years) were randomly allocated into the 20VL group ( n = 8), 40VL group ( n = 7), or control group (CG; n = 8). The RT program consisted of 3 sets of Smith machine back squat exercise at 20VL or 40VL with a 3-minute rest between sets, twice per week for 6 weeks. Tissue oxygenation index (TOI) was measured using near-infrared spectroscopy in the vastus medialis and vastus lateralis during a squat test (8-repetition 1 m·s -1 load test), and the maximum (maxTOI) and minimum (minTOI) TOIs were measured during a 3-min recovery period. After the 6-week RT program, TOI increased significantly at the beginning of the test in both muscles (during the first 4 repetitions in the vastus lateralis and 5 repetitions in the vastus medialis) in the 20VL group ( p < 0.05), with nonsignificant changes in the 40VL group and CG. The maxTOI was significantly increased in the vastus medialis (+3.76%) and vastus lateralis (+3.97%) after the training only in the 20VL group ( p < 0.05). The minTOI in the vastus medialis reached during the test remained unchanged postintervention for both training groups, with the CG showing significantly higher values compared with the 20VL group (+14.1%; p < 0.05). In conclusion, depending on the VL reached during a squat RT program, different changes in muscle oxygen dynamics can be expected. Training at 20% of VL improves metabolic efficiency and the reoxygenation peak after the set., (Copyright © 2023 National Strength and Conditioning Association.)

This study aims to evaluate the differences in body composition, physical function, and physical activity between pre-frail/frail older adults and to detect risk and protective factors against frailty and physical frailty. Fried's criteria for frailty and physical frailty using the short-performance physical battery (SPPB) were measured in 179 older participants (75.3 ± 6.4 years old). Body weight, height, and waist, arm, and leg circumferences were obtained as body composition variables. Daily accelerometer outcomes (physical activity and inactivity) were obtained. Pre-frail participants showed overall better physical function and spent more time in physical activity and less time in long inactivity periods than frail participants ( p < 0.05). Risk frailty factors were higher waist perimeter (Odds Ratio [OR]: 1.032, 95%CI: 1.003-1.062), low leg performance (OR: 1.025, 95%CI: 1.008-1.043), and inactivity periods longer than 30 min (OR:1.002, 95%CI: 1.000-1.005). Protective factors were standing balance (OR:0.908, 95%CI: 0.831-0.992) and SPPB score (OR: 0.908, 95%CI: 0.831-0.992) for frailty, handgrip strength (OR: 0.902, 95%CI: 0.844-0.964) for physical frailty, and light (OR: 0.986, 95%CI: 0.976-0.996) and moderate-to-vigorous (OR: 0.983, 95%CI: 0.972-0.996) physical activity for both. Our findings suggest that handgrip strength, balance, and physical activity are protective frailty factors and can be monitored in pre-frail older adults. Moreover, poor lower body performance and long inactivity periods are frailty risk factors, which highlights their importance in frailty assessment.

This study aims to analyse sex-specific associations of physical activity and sedentary behaviour with oxidative stress and inflammatory markers in a young-adult population. Sixty participants (21 women, 22.63 ± 4.62 years old) wore a hip accelerometer for 7 consecutive days to estimate their physical activity and sedentarism. Oxidative stress (catalase, superoxide dismutase, glutathione peroxidase, glutathione, malondialdehyde, and advanced oxidation protein products) and inflammatory (tumour necrosis factor-alpha and interleukin-6) markers were measured. Student t-tests and single linear regressions were applied. The women presented higher catalase activity and glutathione concentrations, and lower levels of advanced protein-oxidation products, tumour necrosis factor-alpha, and interleukin-6 than the men (p < 0.05). In the men, longer sedentary time was associated with lower catalase activity (β = −0.315, p = 0.04), and longer sedentary breaks and higher physical-activity expenditures were associated with malondialdehyde (β = −0.308, p = 0.04). Vigorous physical activity was related to inflammatory markers in the women (tumour necrosis factor-alpha, β = 0.437, p = 0.02) and men (interleukin−6, β = 0.528, p < 0.01). In conclusion, the women presented a better redox and inflammatory status than the men; however, oxidative-stress markers were associated with physical activity and sedentary behaviours only in the men. In light of this, women could have better protection against the deleterious effect of sedentarism but a worse adaptation to daily physical activity.

Abstract: Muñoz-López, A, Marín-Galindo, A, Corral-Pérez, J, Costilla, M, Sánchez-Sixto, A, Sañudo, B, Casals, C, and Ponce-González, JG. Effects of different velocity loss thresholds on passive contractile properties and muscle oxygenation in the squat exercise using free weights. J Strength Cond Res 36(11): 3056-3064, 2022-The current study assessed the impact between different velocity loss thresholds on changes in the muscle contractile properties and muscle oxygenation after a single resistance training (RT) session. Thirty physically active men participated in a crossover study performing 3 sets of the squat exercise at a lifted speed of ≈0.75 m·s -1 , with 2 different velocity loss thresholds: 20% (VL20) vs 40% (VL40) in a randomized order. Contractile properties of the knee extensor muscles were tested using tensiomyography. In addition, muscle oxygenation was continuously measured from baseline until the end of the exercise session. The vastus lateralis showed a significant moment by condition interaction in time delay ( p = 0.044), muscle displacement ( p = 0.001), and contraction velocity ( p = 0.007), with greater reductions in VL40. In both trainings, oxygenated hemoglobin and tissue oxygen index decreased, whereas deoxygenated hemoglobin increased (moment as the main effect, p < 0.05), but without a moment by condition interaction. VL40 showed a lower deoxygenation slope in set 1 (-0.468%·s -1 , p = 0.001) and set 3 (-0.474%·s -1 , p = 0.037) as well as higher losses in set 1 (-41.50%, p = 0.003), set 2 (-41.84%, p = 0.002), and set 3 (-62.51%, p < 0.001), compared with VL20. No differences were found in the recovery period between conditions. In conclusion, during the RT program design, coaches and athletes should consider that VL40 produces higher mechanical and neuromuscular impairments than VL20, which seems to be necessary for hypertrophy to occur; however, VL40 also produces a longer period of lower oxygen supply than VL20, which can induce fast-to-slow muscle fiber transition., (Copyright © 2021 National Strength and Conditioning Association.)

The present work aimed to examine the association between physical activity (PA) and sedentary behaviour with maximal fat oxidation (MFO) in young individuals. A total of 77 active adults (30 women; 22.8 ± 4.5 years) were included in this cross-sectional study in which PA and sedentary behaviour were measured using accelerometers for 7 consecutive days. PA was classified into different intensities (i.e. light, moderate, vigorous, and moderate-to-vigorous) and sedentary behaviour into sedentary time (i.e. time, number of bouts, and length of bouts) and sedentary breaks (i.e. time, number of breaks, and length of breaks). MFO was determined using a graded cycloergometer test through indirect calorimetry and relativized to lean mass (MFO LM ) and lean leg mass (MFO LL ). Positive associations were found for light and vigorous PA in relation with MFO, MFO LM and MFO LL , independently of cofounders ( P  ≤ 0.01). Moreover, a negative association was found between MFO and MFO LM and the length of sedentary bouts which was accentuated after adjusting by cardiorespiratory fitness ( P  ≤ 0.05). These results suggest that light and vigorous PA and sedentary behaviour are related to MFO during exercise. Despite this, further interventional studies are needed to clarify if increments of light and vigorous PA could enhance MFO in different populations.

This study aimed to analyze the influence of the peroxisome proliferator-activated receptor (PPAR)-gamma coactivator (PGC)-1 alpha (PPARGC1A) gene rs8192678 C>T polymorphism on different health-related parameters in male and female young adults. The PPARGC1A gene rs8192678 polymorphism was ascertained by polymerase chain reaction in 74 healthy adults (28 women; 22.72 ± 4.40 years) from Andalusia (Spain). Health-related variables included cardiometabolic risk, anthropometry and body composition, biochemical parameters, insulin sensitivity (QUICKI and HOMA-IR indexes), blood pressure (BP) at rest and after exercise, diet, basal metabolism, physical activity, maximal fat oxidation, and cardiorespiratory fitness. Our results showed differences by PPARGC1A gene rs8192678 C>T polymorphism in body mass ( p = 0.002), body mass index ( p = 0.024), lean body mass ( p = 0.024), body fat ( p = 0.032), waist circumference ( p = 0.020), and BP recovery ratio ( p < 0.001). The recessive model (CC vs. CT/TT) showed similar results but also with differences in basal metabolism ( p = 0.045) and total energy expenditure ( p = 0.024). A genotype*sex interaction was found in the QUICKI index ( p = 0.016), with differences between CC and CT/TT in men ( p = 0.049) and between men and women inside the CT/TT group ( p = 0.049). Thus, the PPARGC1A gene rs8192678 C>T polymorphism is associated with body composition, basal metabolism, total energy expenditure, and BP recovery, where the CC genotype confers a protective effect. Moreover, our study highlighted sexual dimorphism in the influence of PPARGC1A gene rs8192678 C>T polymorphism on the QUICKI index., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Montes-de-Oca-García, Corral-Pérez, Velázquez-Díaz, Perez-Bey, Rebollo-Ramos, Marín-Galindo, Gómez-Gallego, Calderon-Dominguez, Casals and Ponce-González.)

It is unknown whether resting fat oxidation (RFO), maximal fat oxidation (MFO) and FatMax (intensity at which MFO is reached) are related to cardiometabolic risk (CMR). Thus the aim of this study was to examine the association of RFO, MFO and FatMax with CMR. 81 healthy adults ( n = 31 women; 22.72 ± 4.40 years) participated in this cross-sectional study. Glucose and triglycerides were analysed in plasma. Body composition, anthropometry, physical activity, blood pressure (BP) and heart rate measurements were taken. RFO and MFO were determined through indirect calorimetry. Maximal oxygen uptake (VO 2 max) test was performed until exhaustion after MFO test. The CMR cluster was created from individual CMR factors: waist circumference, body fat percentage, systolic BP, diastolic BP, blood glucose and plasma triglycerides. Groups of high and low MFO and VO 2 max were created. RFO was not associated with CMR ( p < 0.05). FatMax, MFO and VO 2 max were associated with individual CMR factors as waist circumference ( R 2 = 0.144; R 2 = 0.241; R 2 = 0.285; p = 0.001; respectively) and plasma triglycerides ( R 2 = 0.111; p = 0.004 and R 2 = 0.130; p = 0.002 and R 2 = 0.093; p = 0.008; respectively) and clustered CMR factors ( R 2 = 0.105; p = 0.008 and R 2 = 0.162; p = 0.001 and R 2 = 0.239; p = 0.001; respectively). VO 2 max was also associated with body fat percentage ( R 2 = 0.105; p = 0.003) and diastolic BP ( R 2 = 0.083; p = 0.01), even adjusting for sex or age ( p < 0.05). Groups with high level of MFO or VO 2 max obtained lower CMR ( p = 0.001), even adjusting for sex or age ( p < 0.01). FatMax, MFO and, especially, VO 2 max are associated with CMR, regardless of age and sex. However, RFO is not associated with CMR.

There is controversy about the relationship between ACE I/D polymorphism and health. Seventy-four healthy adults ( n = 28 women; 22.5 ± 4.2 years) participated in this cross-sectional study aimed at determining the influence of ACE I/D polymorphism, ascertained by polymerase chain reaction, on cardiometabolic risk (i.e., waist circumference, body fat, blood pressure (BP), glucose, triglycerides, and inflammatory markers), maximal fat oxidation (MFO), cardiorespiratory fitness (maximal oxygen uptake), physical activity and diet. Our results showed differences by ACE I/D polymorphism in systolic BP (DD: 116.4 ± 11.8 mmHg; ID: 116.7 ± 6.3 mmHg; II: 109.4 ± 12.3 mmHg, p = 0.035) and body fat (DD: 27.3 ± 10.8%; ID: 22.6 ± 9.7%; II: 19.3 ± 7.1%, p = 0.030). Interestingly, a genotype*sex interaction in relativized MFO by lean mass ( p = 0.048) was found. The DD polymorphism had higher MFO values than ID/II polymorphisms in men (8.4 ± 3.0 vs. 6.5 ± 2.9 mg/kg/min), while the ID/II polymorphisms showed higher R-MFO values than DD polymorphism in women (6.6 ± 2.3 vs. 7.6 ± 2.6 mg/kg/min). In conclusion, ACE I/D polymorphism is apparently associated with adiposity and BP, where a protective effect can be attributed to the II genotype, but not with cardiorespiratory fitness, diet and physical activity. Moreover, our study highlighted that there is a sexual dimorphism in the influence of ACE I/D gene polymorphism on MFO.

The present study aimed to investigate the effects of a 12-week concurrent training intervention on cardiometabolic health in obese men. Twelve obese men (42.5 ± 5.3 years old) participated in the current 12-week randomized controlled trial with a parallel group design. The participants were randomly assigned to a concurrent training group or to a no-exercise control group. Anthropometry and body composition assessment were determined by electrical bio-impedance. Blood samples were obtained and a cardiometabolic risk Z-Score was calculated. Energy metabolism-related parameters [i.e., resting metabolic rate (RMR), respiratory quotient (RQ), and substrate oxidation in both resting conditions and during exercise] were determined by indirect calorimetry. Echocardiographic studies were performed using an ultrasound system equipped with a transducer to measure cardiac function. A significant decrease of weight (Δ = -4.21 kg; i.e., primary outcome), body mass index (Δ = -1.32 kg/m 2 ), fat mass (FM; Δ = -3.27 kg), blood pressure (BP; Δ = -10.81 mmHg), and cardiometabolic risk Z-Score (Δ = -0.39) was observed in the exercise group compared with the control group (all P < 0.05), while no significant changes were noted in waist circumference (WC), lean mass (LM), bone mineral content, glycemic and lipid profiles, liver function, nor in energy metabolism-related parameters (all P > 0.1). Moreover, a significant increment of left ventricular (LV) end diastolic diameter (Δ = -4.35 mm) was observed in the exercise group compared with the control group ( P = 0.02). A 12-week concurrent training intervention is an effective strategy to induce weight and fat loss with simultaneous reductions of BP and cardiometabolic risk, and improving cardiac function in obese men., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Amaro-Gahete, Ponce-González, Corral-Pérez, Velázquez-Díaz, Lavie and Jiménez-Pavón.)

The present work examines the relationships of objectively measured sedentary time and physical activity (PA) with maximal fat oxidation during exercise (MFO) and the intensity of exercise that elicits MFO (Fat max ), in young and middle-aged men and women. A total of 121 young sedentary adults (81 women, age 22.1 ± 2.1 years, body mass index 25.2 ± 4.9 kg/m 2 ) and 70 middle-aged sedentary adults (36 women, age 53.4 ± 4.9 years, body mass index 26.8 ± 3.8 kg/m 2 ) participated in this cross-sectional study. PA was objectively assessed using a wrist-worn accelerometer for 7 consecutive days. Wrist accelerations were classified into sedentary time and PA of different intensity (light, moderate, vigorous, moderate-vigorous), taking into account age-specific cut-offs. MFO and Fat max were determined for all subjects by indirect calorimetry, using a walking graded exercise test. No association was found between any of the sedentary time-related variables and MFO (all P ≥ .05). However, several sedentary time-related variables were related to FAT max in young men and women (all P ≤ .04). A positive relationship was also detected between PA and MFO in young and middle-aged women (P ≤ .05), although this became non-significant after adjustment for cardiorespiratory fitness (P > .05). The present results suggest that, depending on the characteristics of the study cohort, sedentary time, and PA time may be related to MFO and FAT max during exercise. Future longitudinal and intervention studies are warranted to better understand the role of sedentary time and PA in metabolic flexibility during exercise., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

A device called FeelBreathe (FB) ® was designed, developed, and patented for inspiratory muscle training. The main aim was to determine the acute responses on lung ventilation, gas exchange, and heart rate during exercise in patients with chronic obstructive pulmonary disease (COPD) with and without the use of FB. In this study, a randomized cross-over trial was performed with 18 men diagnosed with COPD (FEV 1 between 30% and 70% of its predicted value). Each participant randomly conducted two trials with 30 min of rest between them with the same protocol on a treadmill for 10 min at a constant rate of 50% of VO 2peak . Each test was performed randomly and in a crossover randomized design in two different conditions: (1) oronasal breathing; and (2) nasal breathing with FB (nasal ventilatory flow restriction device). It was observed that FB had positive effects on dynamic hyperinflation, breathing pattern, and breathing efficiency, with higher expiratory and inspiratory time. Despite these differences, blood oxygen saturation percentage, oxygen uptake, and heart rate showed a similar response for both conditions during exercise. The results suggest that exercise performed with FB improved ventilatory responses compared to the oronasal mode in COPD patients. This new tool could be used during most daily tasks and exercise programs.

Objective: The objective was to assess the effects of a nasal restriction device for inspiratory muscle training, called Feelbreathe ® , added to a rehabilitation program (RP) on exercise capacity, quality of life, dyspnea and inspiratory muscle strength in patients with stable COPD., Methods: Patients were randomized into three groups, one performed a supervised RP using the Feelbreathe ® device (FB group), the second group developed the same RP with oronasal breathing without FB (ONB group) and the third was the control group (CG). We evaluated inspiratory muscle strength (P Imax ), dyspnea (mMRC), quality of life (CAT) and exercise capacity (6MWT) before and after 8-week of RP., Results: A total of 16 patients completed the study, seven in FB group, five in ONB group and four in the CG. After the RP, the FB group showed a significant increase in P Imax (93.3 ± 19.1 vs. 123.0 ± 15.8 mmHg) and in the 6MWT distance (462.9 ± 71.8m vs. 529.1 ± 50.1 m) and a decrease in the CAT score (9.7 ± 6.5 vs. 5.9 ± 6.0) and in the mMRC dyspnea score. FB provides greater improvement in P Imax , dyspnea, quality of life and 6MWT than ONB., Conclusions: The Feelbreathe ® device provides greater improvements in quality of life, dyspnea, exercise capacity and inspiratory muscle strength compared to patients that did not use it., Competing Interests: The authors declare no conflict of interest.

This study aimed to determine whether an active recovery with added whole-body electromyostimulation (WB-EMS) can increase blood flow and lead to blood lactate removal after intense exercise. Thirty-five healthy individuals (23.1 ± 4.6 years) were randomly assigned to: (a) an experimental group using active recovery together with the WB-EMS ( n = 18) or (b) a control group using the same active recovery protocol with the suit with no-stimulation (CON, n = 17). Participants performed a maximal graded exercise test followed by an active recovery protocol (walking at 40% of their maximum aerobic velocity). During the recovery, participants in WB-EMS and CON received continuous stimulation at 7 Hz or no stimulation, respectively. Heart rate, blood lactate concentrations, pain/discomfort, and hemodynamic measurements were recorded before and after the test, and repeated immediately after and at min 30 and 60. The between-group analysis showed a substantially greater Peak blood velocity (-0.27 [-0.68; 0.14]) in WB-EMS compared to CON. The pain/discomfort levels were also lower in WB-EMS compared with CON (0.66 [-0.12; 1.45]). Non-significant differences in participants' blood lactate were observed in WB-EMS compared with CON both immediately; at 30and 60 min. Our findings suggest that increased local blood flow induced by WB-EMS may have contributed to greater lactate removal from active muscles and blood lactate clearance. WB-EMS may be an effective means of increasing muscle blood flow after a maximal graded exercise test and could result in improved recovery., (Copyright © 2020 Sañudo, Bartolomé, Tejero, Ponce-González, Loza and Figueroa.)

The aim of this study was to compare the hamstring flexibility between federated soccer and non-federated adolescents, and also to evaluate the effect of age and weight status on hamstring flexibility. The participants were 234 students (11-18 years old) divided into: (i) G1: non-federated (n = 127), and (ii) G2: federated in soccer (n = 107). The deep flexion of the trunk (DF) test and the sit and reach test (SRT) were performed. G2 showed higher values for the DF and SRT compared to G1 ( p < 0.05). Both flexibility tests correlated positively (r = 0.4, p < 0.001). Body mass index (BMI) was negatively correlated with the DF test (r = -0.3, p < 0.001), but not with the SRT. Divided by BMI, the underweight and normal weight groups had higher scores in the DF test compared with the overweight and obese groups ( p < 0.001). BMI was negatively correlated with hamstring flexibility. Federated soccer students present higher scores of hamstring flexibility.

The objective of this study was to analyse the sun exposure habits of elite aquatics athletes, together with their sunburn history and skin examination habits, taking into account differences by sex and between sports. A cross-sectional health survey was conducted at world championship events during which elite surfers, windsurfers and Olympic sailors from 30 different countries were invited to participate. The athletes were asked to complete a self-administered questionnaire focused on sun protection habits, sun exposure and sports practices. The survey was completed by 240 athletes, 171 men (71.3%) and 69 women (28.8%), with a mean age of 22 years (SD 5.86) and skin phototypes I (6.3%), II (3.3%), III (22.0%), IV (32.5%), V (9.2%) and VI (1.7%). There were significant differences between male and female athletes in skin self-examination (p < 0.001) and in the use of sunglasses (p < 0.001). In sunburn history during the last season, there were significant differences (p < 0.001) among the three sports analysed, in both sexes. The mean rate of sunburn during the previous season was 76.7%, and 27.5% of participants reported having experienced three or more sunburns that lasted at least 1 day. This type of athlete is at high risk of sunburn and hence of future skin cancer. However, there is a general lack of awareness of this risk. This study highlights the need to inform such athletes and to raise awareness of the dangers, through educational interventions on the importance of protecting against sunburn in order to reduce the future incidence of skin cancer.

Introduction: Unhealthy lifestyle and inadequate diet could influence the development of future cardiometabolic disease. The main aim of this study was to determine the association between aerobic fitness and cardiometabolic risk factors in adults, whether this relation is depends of adherence to Mediterranean diet (MD). A secondary aim was to study the combined effect of aerobic capacity and adherence to MD on global cardiometabolic risk score (CMRS)., Method: A total of 79 adults (38% women) enrolled between 18-40 year from Cádiz. We measured adiposity indicators, blood pressure, triglycerides, glucose and inflammatory profile (interleukin-6 and tumor necrosis factor) and was computed (CMRS). Aerobic fitness was measured by maximal oxygen comsuption through an incremental stress test by cycleergometer. The MD patterns was measured using the questionnaire of adherence to MD. The association between aerobic fitness and cardiometabolic risk factors was examined using a lineal regression and it was adjusted for different confounders. CMRS on the lifestyle was analyzed using the ANOVA test, with statistical significance level of P<0.05 in Bonferroni., Results: Linear regression showed inverse association between aerobic fitness and cardiometabolic risk factors (all P≤0.05) in the model without adjustment. Blood pressure and triglycerides lost the association after adjust model for sex, age, and adherence to MD. Participants with high aerobic fitness and high adherence to MD show a lowest CMRS (-1.083±2.325 vs. 2.802±1.759)., Conclusions: Aerobic fitness was inversely associated with fatness risk factors, that relationship is independent to adherence to MD. A high adherence to MD could modulate blood pressure. A combination of high aerobic capacity and high adherence to MD could reduce the adverse consecuence of a low adherencie to MD., (Copyright © 2019 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: No consensus exists on how to average data to optimize V ˙ O 2max assessment. Although the V ˙ O 2max value is reduced with larger averaging blocks, no mathematical procedure is available to account for the effect of the length of the averaging block on V ˙ O 2max. AIMS: To determine the effect that the number of breaths or seconds included in the averaging block has on the V ˙ O 2max value and its reproducibility and to develop correction equations to standardize V ˙ O 2max values obtained with different averaging strategies., Methods: Eighty-four subjects performed duplicate incremental tests to exhaustion (IE) in the cycle ergometer and/or treadmill using two metabolic carts (Vyntus and Vmax N29). Rolling breath averages and fixed time averages were calculated from breath-by-breath data from 6 to 60 breaths or seconds., Results: V ˙ O 2max decayed from 6 to 60 breath averages by 10% in low fit ( V ˙ O 2max  < 40 mL kg -1  min -1 ) and 6.7% in trained subjects. The V ˙ O 2max averaged from a similar number of breaths or seconds was highly concordant (CCC > 0.97). There was a linear-log relationship between the number of breaths or seconds in the averaging block and V ˙ O 2max (R 2  > 0.99, P < 0.001), and specific equations were developed to standardize V ˙ O 2max values to a fixed number of breaths or seconds. Reproducibility was higher in trained than low-fit subjects and not influenced by the averaging strategy, exercise mode, maximal respiratory rate, or IE protocol., Conclusions: The V ˙ O 2max decreases following a linear-log function with the number of breaths or seconds included in the averaging block and can be corrected with specific equations as those developed here., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Exercise and protein ingestion preserve muscle mass during moderate energy deficits., Objective: To determine the molecular mechanisms by which exercise and protein ingestion may spare muscle mass during severe energy deficit (5500 kcal/day)., Design: Fifteen overweight, but otherwise healthy men, underwent a pre-test (PRE), caloric restriction (3.2 kcals/kg body weight/day) + exercise (45 min one-arm cranking + 8 h walking) for 4 days (CRE), followed by a control diet (CD) for 3 days, with a caloric content similar to pre-intervention while exercise was reduced to less than 10,000 steps per day. During CRE, participants ingested either whey protein (PRO, n = 8) or sucrose (SU, n = 7) (0.8 g/kg body weight/day). Muscle biopsies were obtained from the trained and untrained deltoid, and vastus lateralis., Results: Following CRE and CD, serum concentrations of leptin, insulin, and testosterone were reduced, whereas cortisol and the catabolic index (cortisol/total testosterone) increased. The Akt/mTor/p70S6K pathway and total eIF2α were unchanged, while total 4E-BP1 and Thr 37/46 4E-BP1 were higher. After CRE, plasma BCAA and EAA were elevated, with a greater response in PRO group, and total GSK3β, pSer 9 GSK3β, pSer 51 eIF2α, and pSer 51 eIF2α/total eIF2α were reduced, with a greater response of pSer 9 GSK3β in the PRO group. The changes in signaling were associated with the changes in leptin, insulin, amino acids, cortisol, cortisol/total testosterone, and lean mass., Conclusions: During severe energy deficit, pSer 9 GSK3β levels are reduced and human skeletal muscle becomes refractory to the anabolic effects of whey protein ingestion, regardless of contractile activity. These effects are associated with the changes in lean mass and serum insulin, testosterone, and cortisol concentrations.

Furr, HN, Warner, ME, Copeland, TL, Robles-Rodríguez, C, Ponce-González, JG, Nessler, JA, and Newcomer, SC. Differences in V[Combining Dot Above]O2peak of surfers when paddling in water vs. on a swimbench ergometer. J Strength Cond Res 33(4): 1095-1101, 2019-The purpose of this study was to test the hypothesis that surfers would achieve a higher V[Combining Dot Above]O2peak when tested in a swim flume vs. on a swimbench ergometer. Forty-eight surfers (male: 38, female: 10) aged 18-45 years participated in the study. Protocol 1 and 2 both measured heart rate, oxygen consumption (V[Combining Dot Above]O2), and respiratory exchange ratio while subjects performed an incremental paddling test both on a swimbench ergometer and in a swim flume. Protocol 2 additionally measured muscle activity and changes in skin temperature. V[Combining Dot Above]O2peak was significantly higher in the swim flume (33.03 ± 1.04 ml·kg·min) vs. on the swimbench ergometer (29.86 ± 1.08 ml·kg·min) (p value < 0.001). There were also significant differences in muscle activation and changes in skin temperature between the flume and ergometer (p-value < 0.05). Surfers significantly increased their V[Combining Dot Above]O2peak in the water suggesting previous reports of V[Combining Dot Above]O2peak likely underestimated surfer's aerobic fitness when measured on a swimbench ergometer. Future research investigating the aerobic fitness of surfers should be conducted while paddling in water or account for the 11% difference in V[Combining Dot Above]O2peak when tested on a swimbench ergometer.

The "Century XXI" Project is a seven-year intervention sport program performed among the best Spanish youth basketball players, who were assigned to one of the following intervention groups based on the following criteria: age, position, mature level, and origin in the country. The study was performed (1996-2001) with a total of 90 players. The main purposes of this study were: a) to describe anthropometric and performance characteristics of top youth international male basketballers in the Spanish national academy; and b) to analyze differences among positions. Insummary, the main findings of this study were: a) the anthropometry presented significant differences between groups under (U-) 14 and U-17; and b) in the U-17 group centers presented more arm span. In our study, the most significant changes are in U-16 vs U-14 and U-15 in strength body up values, and the best result in endurance capacity took place in June of the fourth year. Within this context, the results of the present study may be useful for strength and conditioning coaches to plan their programs with youth basketball players.

Background: The inertial flywheel device causes an increase in eccentric overload during training. The aim was to study muscle oxygen saturation produced during an inertial flywheel squat training, comparing it with a barbell squat training., Methods: Twelve male adults performed a barbell squat training (3×8 reps, 75-80% 1RM) and a flywheel squat training (3×8 reps, all-out). Muscle oxygen saturation (%SmO2), total hemoglobin (tHb), reoxygenation, heart rate (HR), lactate, vertical jumps, maximal voluntary isometric contraction and rated perceived exertion (RPE) were studied., Results: Both protocols produced a significant decrease in %SmO2 and tHB during the sets of squats, and a significant increase in HR, lactates dand RPE after training. The flywheel squat protocol caused a greater decrease in %SmO2 than the barbell squat protocol in each of the sets of exercises (1st set: -67.5±7.2% vs. -53.7±16.2%; 2nd set: -67.2±13.5% vs. -53.6±15.4%; 3rd set: -68.1±13.0% vs. -55.0±17.0%), as well as a longer reoxygenation after finishing the training (61.7±12.6 vs. 55.7±13.7 s)., Conclusions: Although no differences were found on a muscle fatigue level, the flywheel training brought on greater physiological stress than the barbell squat training, observing a greater decrease in muscle oxygen saturation and a longer reoxygenation.

We tested the mediating effect of leptin on the association between physical fitness (PF) components and academic performance indicators in healthy adolescents. A total of 263 adolescents (13.9 ± 0.3 years, 47.5% girls, 12.5% overweight) from the DADOS (Deporte, ADOlescencia y Salud) Study were included in the analysis. PF components were assessed by the handgrip test for upper-limb muscular strength, standing long jump test for lower-limb muscular strength, 4 × 10-m shuttle run test for speed-agility, and 20-m shuttle run test for cardiorespiratory fitness. Plasma leptin concentration was assessed from antecubital vein blood after an overnight fast using a sensitive ELISA kit. Academic performance indicators were assessed through final school grades and through the Spanish version of the SRA Test of Educational Ability. Body composition was assessed by body mass index and skinfold thicknesses. Boot-strapped mediation procedures were performed and indirect effects with confidence intervals not including zero were interpreted as statistically significant. Our findings suggest that the positive associations observed between cardiorespiratory fitness and lower-limb muscular strength with academic performance indicators were mediated by leptin concentration after adjusting for sex, pubertal stage, socioeconomic status, and adiposity (percentage of mediation ranging from 54.61 to 82.02%)., Conclusions: Improvements on PF components, particularly in cardiorespiratory fitness and lower-limb muscular strength, might reduce leptin concentration with potential benefits on academic performance in adolescents, independently of adiposity. What is Known: • Academic performance is associated with physical fitness and leptin concentration in children and adolescents. • Fitness modulates leptin concentration levels, regardless of physical activity and adiposity. What is New: • Leptin concentration mediates the association of cardiorespiratory fitness and muscular strength with academic performance in adolescents. • Improvements in cardiorespiratory fitness and muscular strength might reduce leptin concentration levels enhancing academic performance.

Aims: To evaluate the knowledge of teachers in educative public centres (pre-, primary, and secondary schools) about type 1 diabetes (T1D) in the Puerto Real University Hospital area (Cadiz, Spain)., Methods: Descriptive observational study in which 756 teachers' answers on the Test of Diabetes Knowledge for Teachers (TDKT) were analysed. Teachers from 44 educative public centres in the Puerto Real University Hospital area (Cadiz, Spain) were selected by randomized sampling (mean age, 44.3 ± 8 years; 61.7% women)., Results: Although 43.2% survey respondents recognised having had or currently having children or adolescent students with T1D, most demonstrated they did not have enough knowledge about T1D (mean score, 6.0 ± 4.3 points from a maximum of 16), and only 5.1% had sufficient knowledge (13-16 points) to be an effective support person to students with diabetes in school. However, the vast majority of survey respondents correctly answered questions about symptoms (74.2%) and hypoglycaemia treatment (85.9%). Univariate analysis of factors associated with teachers' knowledge about diabetes revealed that teachers with ≤ 15 years of teaching experience and physical education teachers had better knowledge than their co-workers., Conclusions: It is necessary to improve teachers' knowledge about diabetes in our health area with the aim of improving the security of children and adolescent students with T1D in school centres., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objective: To assess teachers' attitudes and perceptions about preparation of public primary and secondary education schools in the Puerto Real University Hospital (Cádiz, Spain) area to care for students with type 1 diabetes mellitus (T1DM) METHODS: A descriptive observational study where answers to an attitude and perception questionnaire on the preparation of schools to care for pupils with T1DM were analyzed. A total of 765 teachers (mean age, 44.3±8.8 years; 61.7% women) from 44 public schools in the area of the Puerto Real University Hospital were selected by random sampling., Results: Overall, 43.2% of teachers surveyed had or had previously had students with T1DM, but only 0.8% had received specific training on diabetes. 18.9% of teachers reported that one of their students with T1DM had experienced at least one episode of hypoglycemia at school, and half of them felt that their school was not prepared to deal with diabetic emergencies. 6.4% stated that their school had glucagon in its first aid kit, and 46.9% would be willing to administer it personally. Women, physical education teachers, and headmasters had a more positive perception of the school than their colleagues. Teachers with a positive perception of school preparation and with a positive attitude to administer glucagon were significantly younger than those with no positive perception and attitude., Conclusions: The study results suggest that teachers of public schools in our health area have not been specifically trained in the care of patients with T1DM and perceive that their educational centers are not qualified to address diabetic emergencies., (Copyright © 2017 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.)

The aim of this study was to determine if reactive oxygen species (ROS) could play a role in blunting Thr 172 -AMP-activated protein kinase (AMPK)-α phosphorylation in human skeletal muscle after sprint exercise in hypoxia and to elucidate the potential signaling mechanisms responsible for this response. Nine volunteers performed a single 30-s sprint (Wingate test) in two occasions while breathing hypoxic gas ([Formula: see text] = 75 mmHg): one after the ingestion of placebo and another following the intake of antioxidants (α-lipoic acid, vitamin C, and vitamin E), with a randomized double-blind design. Vastus lateralis muscle biopsies were obtained before, immediately after, and 30- and 120-min postsprint. Compared with the control condition, the ingestion of antioxidants resulted in lower plasma carbonylated proteins, attenuated elevation of the AMP-to-ATP molar ratio, and reduced glycolytic rate ( P < 0.05) without significant effects on performance or V̇o 2 The ingestion of antioxidants did not alter the basal muscle signaling. Thr 172 -AMPKα and Thr 184/187 -transforming growth factor-β-activated kinase 1 (TAK1) phosphorylation were not increased after the sprint regardless of the ingestion of antioxidants. Thr 286 -CaMKII phosphorylation was increased after the sprint, but this response was blunted by the antioxidants. Ser 485 -AMPKα1/Ser 491 -AMPKα2 phosphorylation increased immediately after the sprints coincident with increased Akt phosphorylation. In summary, antioxidants attenuate the glycolytic response to sprint exercise in severe acute hypoxia and modify the muscle signaling response to exercise. Ser 485 -AMPKα1/Ser 491 -AMPKα2 phosphorylation, a known mechanism of Thr 172 -AMPKα phosphorylation inhibition, is increased immediately after sprint exercise in hypoxia, probably by a mechanism independent of ROS. NEW & NOTEWORTHY The glycolytic rate is increased during sprint exercise in severe acute hypoxia. This study showed that the ingestion of antioxidants before sprint exercise in severe acute hypoxia reduced the glycolytic rate and attenuated the increases of the AMP-to-ATP and the reduction of the NAD + -to-NADH.H + ratios. This resulted in a modified muscle signaling response with a blunted Thr 286 -CaMKII but similar AMP-activated protein kinase phosphorylation responses in the sprints preceded by the ingestion of antioxidants., (Copyright © 2017 the American Physiological Society.)

In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt -1 ·day -1 ) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein ( n = 8) or sucrose ( n = 7; 0.8 g·kg body wt -1 ·day -1 ). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr 1141 OBR, phospho-Tyr 985 OBR, JAK2, and phospho-Tyr 1007/1008 JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr 705 STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively ( P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression ( r  = -0.75), phospho-Tyr 985 OBR ( r  = 0.88), and phospho-Tyr 705 STAT3/STAT3 ( r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles. NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling., (Copyright © 2017 the American Physiological Society.)

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.

Introduction: Regular physical activity (PA) can reduce the risk of developing type 2 diabetes, but adherence to time-orientated (150 min week -1 or more) PA guidelines is very poor. A practical and time-efficient PA regime that was equally efficacious at controlling risk factors for cardio-metabolic disease is one solution to this problem. Herein, we evaluate a new time-efficient and genuinely practical high-intensity interval training (HIT) protocol in men and women with pre-existing risk factors for type 2 diabetes., Materials and Methods: One hundred eighty-nine sedentary women ( n  = 101) and men ( n  = 88) with impaired glucose tolerance and/or a body mass index >27 kg m -2 [mean (range) age: 36 (18-53) years] participated in this multi-center study. Each completed a fully supervised 6-week HIT protocol at work-loads equivalent to ~100 or ~125% [Formula: see text]. Change in [Formula: see text] was used to monitor protocol efficacy, while Actiheart™ monitors were used to determine PA during four, weeklong, periods. Mean arterial (blood) pressure (MAP) and fasting insulin resistance [homeostatic model assessment (HOMA)-IR] represent key health biomarker outcomes., Results: The higher intensity bouts (~125% [Formula: see text]) used during a 5-by-1 min HIT protocol resulted in a robust increase in [Formula: see text] (136 participants, +10.0%, p  < 0.001; large size effect). 5-by-1 HIT reduced MAP (~3%; p  < 0.001) and HOMA-IR (~16%; p  < 0.01). Physiological responses were similar in men and women while a sizeable proportion of the training-induced changes in [Formula: see text], MAP, and HOMA-IR was retained 3 weeks after cessation of training. The supervised HIT sessions accounted for the entire quantifiable increase in PA, and this equated to 400 metabolic equivalent (MET) min week -1 . Meta-analysis indicated that 5-by-1 HIT matched the efficacy and variability of a time-consuming 30-week PA program on [Formula: see text], MAP, and HOMA-IR., Conclusion: With a total time-commitment of <15 min per session and reliance on a practical ergometer protocol, 5-by-1 HIT offers a new solution to modulate cardio-metabolic risk factors in adults with pre-existing risk factors for type 2 diabetes while approximately meeting the MET min week -1 PA guidelines. Long-term randomized controlled studies will be required to quantify the ability for 5-by-1 HIT to reduce the incidence of type 2 diabetes, while strategies are required to harmonize the adaptations to exercise across individuals.

The loss of fat-free mass (FFM) caused by very-low-calorie diets (VLCD) can be attenuated by exercise. The aim of this study was to determine the role played by exercise and dietary protein content in preserving the lean mass and performance of exercised and non-exercised muscles, during a short period of extreme energy deficit (~23 MJ deficit/day). Fifteen overweight men underwent three consecutive experimental phases: baseline assessment (PRE), followed by 4 days of caloric restriction and exercise (CRE) and then 3 days on a control diet combined with reduced exercise (CD). During CRE, the participants ingested a VLCD and performed 45 min of one-arm cranking followed by 8 h walking each day. The VLCD consisted of 0.8 g/kg body weight/day of either whey protein (PRO, n = 8) or sucrose (SU, n = 7). FFM was reduced after CRE ( P < 0.001), with the legs and the exercised arm losing proportionally less FFM than the control arm [57% ( P < 0.05) and 29% ( P = 0.05), respectively]. Performance during leg pedaling, as reflected by the peak oxygen uptake and power output (Wpeak), was reduced after CRE by 15 and 12%, respectively ( P < 0.05), and recovered only partially after CD. The deterioration of cycling performance was more pronounced in the whey protein than sucrose group ( P < 0.05). Wpeak during arm cranking was unchanged in the control arm, but improved in the contralateral arm by arm cranking. There was a linear relationship between the reduction in whole-body FFM between PRE and CRE and the changes in the cortisol/free testosterone ratio (C/FT), serum isoleucine, leucine, tryptophan, valine, BCAA, and EAA ( r = -0.54 to -0.71, respectively, P < 0.05). C/FT tended to be higher in the PRO than the SU group following CRE ( P = 0.06). In conclusion, concomitant low-intensity exercise such as walking or arm cranking even during an extreme energy deficit results in remarkable preservation of lean mass. The intake of proteins alone may be associated with greater cortisol/free testosterone ratio and is not better than the ingestion of only carbohydrates for preserving FFM and muscle performance in interventions of short duration.

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.

To determine the influence of androgen receptor CAG and GGN repeat polymorphisms on fat mass and maximal fat oxidation (MFO), CAG and GGN repeat lengths were measured in 128 young boys, from which longitudinal data were obtained in 45 of them [mean ± SD: 12.8 ± 3.6 years old at recruitment, and 27.0 ± 4.8 years old at adult age]. Subjects were grouped as CAG short (CAG S ) if harboring repeat lengths ≤  21, the rest as CAG long (CAG L ); and GGN short (GGN S ) if GGN repeat lengths ≤  23, or long if >  23 (GGN L ). CAG S and GGN S were associated with lower adiposity than CAG L or GGN L (P < 0.05). There was an association between the logarithm of CAG repeats polymorphism and the changes of body mass (r = 0.34, P = 0.03). At adult age, CAG S men showed lower accumulation of total body and trunk fat mass, and lower resting metabolic rate (RMR) and MFO per kg of total lean mass compared with CAG L (P < 0.05). GGN S men also showed lower percentage of body fat (P < 0.05). In summary, androgen receptor CAG and GGN repeat polymorphisms are associated with RMR, MFO, fat mass, and its regional distribution in healthy male adolescents, influencing fat accumulation from adolescence to adult age., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

To determine the level of hypoxia from which muscle activation (MA) is reduced during incremental exercise to exhaustion (IE), and the role played by PIO2 in this process, ten volunteers (21 ± 2 years) performed four IE in severe acute hypoxia (SAH) (PIO2 = 73 mmHg). Upon exhaustion, subjects were asked to continue exercising while the breathing gas mixture was swiftly changed to a placebo (73 mmHg) or to a higher PIO2 (82, 92, 99, and 142 mmHg), and the IE continued until a new exhaustion. At the second exhaustion, the breathing gas was changed to room air (normoxia) and the IE continued until the final exhaustion. MA, as reflected by the vastus medialis (VM) and lateralis (VL) EMG raw and normalized root mean square (RMSraw, and RMSNz, respectively), normalized total activation index (TAINz), and burst duration were 8-20% lower at exhaustion in SAH than in normoxia (P < 0.05). The switch to a placebo or higher PIO2 allowed for the continuation of exercise in all instances. RMSraw, RMSNz, and TAINz were increased by 5-11% when the PIO2 was raised from 73 to 92, or 99 mmHg, and VL and VM averaged RMSraw by 7% when the PIO2 was elevated from 73 to 142 mmHg (P < 0.05). The increase of VM-VL average RMSraw was linearly related to the increase in PIO2, during the transition from SAH to higher PIO2 (R (2) = 0.915, P < 0.05). In conclusion, increased PIO2 at exhaustion reduces fatigue and allows for the continuation of exercise in moderate and SAH, regardless of the effects of PIO2 on MA. At task failure, MA is increased during the first 10 s of increased PIO2 when the IE is performed at a PIO2 close to 73 mmHg and the PIO2 is increased to 92 mmHg or higher. Overall, these findings indicate that one of the central mechanisms by which severe hypoxia may cause central fatigue and task failure is by reducing the capacity for reaching the appropriate level of MA to sustain the task. The fact that at exhaustion in severe hypoxia the exercise was continued with the placebo-gas mixture demonstrates that this central mechanism has a cognitive component.

Background: Impaired fat oxidation is linked to cardiometabolic risk. Maximal fat oxidation rate (MFO) reflects metabolic flexibility and is influenced by lean mass, muscle strength, muscle quality - defined as the ratio of strength to mass - and cardiorespiratory fitness. The relationship between these factors and fat oxidation is not fully understood. The aim is to analyze the associations of lean-mass, muscle strength and quality with fat oxidation parameters in young adults, considering the mediating role of VO 2 max., Methods: A cross-sectional observational study. Eighty-one adults (50 males, 31 females; age 22.8 ± 4.4, BMI 25.70 ± 5.75, lean-mass 54.19 ± 8.78, fat-mass 18.66 ± 11.32) Body composition assessment by bioimpedance determine fat and lean-mass. Indirect calorimetry at rest and exercise was used for the calculation of fat oxidation. An incremental exercise protocol in a cycle ergometer with two consecutive phases was performed. The first to determine MFO consisted of 3 min steps of 15W increments with a cadence of 60rpm. The test was stopped when RQ ≥ 1. After 5 min rest, a phase to detect VO 2 max began with steps of 15W/min until exhaustion. Muscular strength was assessed by handgrip dynamometry and the standing longitudinal jump test. A strength cluster was calculated with handgrip and long jump adjusted by sex and age. Data were analyzed using multiple linear regression and mediation analyses., Results: Total lean-mass and leg lean-mass were not associated with MFO. Long jump, relativized by lean-mass and by leg lean-mass have a standardized indirect effect on MFO of 0.50, CI: 0.32-0.70, on MFO/lean-mass 0.43, CI:0.27-0.60 and MFO/leg lean-mass 0.44, CI: 0.30-0.06, which VO 2 max mediated, VO 2 max/lean-mass and VO 2 max/leg lean-mass, respectively (all p  < 0.01). The handgrip/arm lean-mass had an indirect effect of 0.25 (CI: 0.12-0.38) on MFO/leg lean-mass, with VO 2 max/leg lean-mass as the mediator ( p  < 0.01). The Cluster/lean-mass and Cluster/Extremities lean-mass have a standardized indirect effect on MFO/lean-mass (0.34, CI: 0.20-0.48) and MFO/leg lean-mass (0.44, CI: 0.28-0.60), mediated by VO2max/lean-mass and VO2max/leg lean-mass ( p  < 0.01)., Conclusions: Muscular strength and quality have an indirect effect on MFO mediated by VO 2 max. These findings suggest the importance of muscle quality on MFO.

Purpose: The aim of this study was to determine if the expression of the mitochondrial biogenesis-regulating proteins SIRT1, SIRT3 and PGC-1alpha in human skeletal muscle is influenced by adiposity., Method: Twenty-nine male subjects were recruited into three groups: control (n = 10), obese (n = 10) and post-obese (n = 9). Intentionally, groups were matched by age, aerobic capacity and in addition the control and post-obese groups also by BMI. Muscle biopsies were obtained from the m. deltoid and vastus lateralis. PGC-1alpha, SIRT1 and SIRT3 protein expression was analyzed by Western blot., Result: PGC-1alpha, SIRT1 and SIRT3 protein expression was similar regardless of the level of adiposity. Only a main effect of group on SIRT1 protein showed a trend toward higher expression in post-obese than control and obese (P = 0.09). Despite similar muscle fiber-type composition (previously reported), PGC-1alpha, SIRT1 and SIRT3 protein expression was higher in leg compared to arm muscle in all groups (P < 0.05)., Conclusion: This study shows that PGC-1alpha, SIRT1 and SIRT3 protein expression in basal conditions was not altered in humans with different levels of adiposity but similar aerobic capacity. The expression of PGC-1alpha, SIRT1 and SIRT3 was higher in vastus lateralis than in deltoid muscle, indicating that local rather than systemic factors prevail in regulating the level of expression of these proteins.

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)ACCβ, 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)ACCβ 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.

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., (© 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.)

To determine the mechanisms causing task failure during incremental exercise to exhaustion (IE), sprint performance (10 s all-out isokinetic) and muscle metabolites were measured before (control) and immediately after IE in normoxia (P(IO2) 143 mmHg) and hypoxia (P(IO2): 73 mmHg) in 22 men (22 ± 3 years). After IE, subjects recovered for either 10 or 60 s, with open circulation or bilateral leg occlusion (300 mmHg) in random order. This was followed by a 10 s sprint with open circulation. Post-IE peak power output (W(peak)) was higher than the power output reached at exhaustion during IE (P < 0.05). After 10 and 60 s recovery in normoxia, W(peak) was reduced by 38 ± 9 and 22 ± 10% without occlusion, and 61 ± 8 and 47 ± 10% with occlusion (P < 0.05). Following 10 s occlusion, W(peak) was 20% higher in hypoxia than normoxia (P < 0.05), despite similar muscle lactate accumulation ([La]) and phosphocreatine and ATP reduction. Sprint performance and anaerobic ATP resynthesis were greater after 60 s compared with 10 s occlusions, despite the higher [La] and [H(+)] after 60 s compared with 10 s occlusion recovery (P < 0.05). The mean rate of ATP turnover during the 60 s occlusion was 0.180 ± 0.133 mmol (kg wet wt)(-1) s(-1), i.e. equivalent to 32% of leg peak O2 uptake (the energy expended by the ion pumps). A greater degree of recovery is achieved, however, without occlusion. In conclusion, during incremental exercise task failure is not due to metabolite accumulation or lack of energy resources. Anaerobic metabolism, despite the accumulation of lactate and H(+), facilitates early recovery even in anoxia. This points to central mechanisms as the principal determinants of task failure both in normoxia and hypoxia, with lower peripheral contribution in hypoxia., (© 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.)

Unlabelled: The effects of basketball on basal concentrations of testosterone and cortisol and its associations to body composition and physical performance remain to be determined., Aim: The main aim of this study was to determine the effects of playing position on physical fitness, percentage of body fat and hormonal profile in professional basketball players (BP)., Method: Jump performance (SJ, CMJ and ABK), 30 m running speed and treadmill VO2max tests were conducted in 12 male BP (24.1 years) from the first division league of Spain (ACB). The percentage of body fat was determined from anthropometry, and hemoglobin, glucose, testosterone and cortisol concentrations were measured from fasting blood samples. BP were divided into 3 groups depending on playing positions: guards (GU), forwards (FW) and centers (CE) (n = 4 in each group)., Results: GU had greater percentage of body fat (%BF) than CE (p < 0.05). CE developed greater positive mechanical impulse than GU in all jump types (p < 0.05) and achieved higher maximal instantaneous power than GU and FW in the SJ and ABK (p < 0.05). Centers had more plasma testosterone than guards (p < 0.05). All groups a similar relative VO2max., Conclusion: Center position was associated to lower adiposity and higher jumping performance than playing as guards. All playing positions induced a similar effect on aerobic power., (Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.)

To determine whether a fast reduction in fat mass can be achieved in 4 days by combining caloric restriction (CR: 3.2 kcal/kg body weight per day) with exercise (8-h walking + 45-min arm cranking per day) to induce an energy deficit of ∼5000 kcal/day, 15 overweight men underwent five experimental phases: pretest, exercise + CR for 4 days (WCR), control diet + reduced exercise for 3 days (DIET), and follow-up 4 weeks (POST1) and 1 year later (POST2). During WCR, the diet consisted solely of whey protein (n = 8) or sucrose (n = 7) (0.8 g/kg body weight per day). After WCR, DIET, POST1, and POST2, fat mass was reduced by a mean of 2.1, 2.8, 3.8, and 1.9 kg (P < 0.05), with two thirds of this loss from the trunk; and lean mass by 2.8, 1.0, 0.5, and 0.4 kg, respectively. After WCR, serum glucose, insulin, homeostatic model assessment, total and low-density lipoprotein cholesterol and triglycerides were reduced, and free fatty acid and cortisol increased. Serum leptin was reduced by 64%, 50%, and 33% following WCR, DIET, and POST1, respectively (P < 0.05). The effects were similar in both groups. In conclusion, a clinically relevant reduction in fat mass can be achieved in overweight men in just 4 days by combining prolonged exercise with CR., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The aim was to develop a unipedal stance test for the assessment of balance using a force platform., Methods: A single-leg balance test was conducted in 23 students (mean ± SD) age: 23 ± 3 years) in a standard position limiting the movement of the arms and non-supporting leg. Six attempts, with both the jumping (JL) and the contralateral leg (CL), were performed under 3 conditions: 1) eyes opened; 2) eyes closed; 3) eyes opened and executing a precision task. The same protocol was repeated two-week apart., Results: The mean and the best result of the six attempts performed each day were taken as representative of balance. The speed of the centre of pressure (CP-Speed) showed excellent reliability for the "best result" analysis in all tests (ICCs 0.87-0.97), except in the test with the eyes closed performed on the CL (ICC<0.4). The CP-Speed had better reliability with the "best result" than with the "mean result" analysis (P<0.05), whilst no significant differences were observed between the JL and the CL (P=0.71 and P=0.96 for mean and best results analysis, respectively). A lower dispersion in the Bland and Altman graph was observed with the eyes opened than closed, and the dynamic test., Conclusion: The single-leg stance balance test proposed is a reliable method to assess balance, especially when performed in a static position, with the eyes opened and using the best result of six attempts as reference, independently of the stance leg.

Purpose: This study aimed at determining the effects of bed rest on the skeletal muscle leptin signaling system., Methods: Deltoid and vastus lateralis muscle biopsies and blood samples were obtained from 12 healthy young men (mean ± SD, BMI 22.8 ± 2.7 kg/m(2)) before and after 7 days of bed rest. Leptin receptor isoforms (OB-Rs), suppressor of cytokine signaling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) protein expression and signal transducer and activator of transcription 3 (STAT3) phosphorylation were analyzed by Western blot., Results: After bed rest basal insulin concentration was increased by 53% (P < 0.05), the homeostasis model assessment (HOMA) by 40% (P < 0.05), and serum leptin concentration by 35% (P < 0.05) with no changes in body fat mass. Although the soluble isoform of the leptin receptor (s-OBR) remained unchanged, the molar excess of leptin over sOB-R was increased by 1.4-fold after bed rest (P < 0.05). OB-Rs and SOCS3 protein expression, and STAT3 phosphorylation level remained unaffected in deltoid and vastus lateralis by bed rest, as PTP1B in the deltoid. PTP1B was increased by 90% with bed rest in the vastus lateralis (P < 0.05). There was a linear relationship between the increase in vastus lateralis PTP1B and the increase in both basal insulin concentrations (r = 0.66, P < 0.05) and HOMA (r = 0.68, P < 0.05) with bed rest., Conclusions: One week of bed rest is associated with increased leptin levels without augmenting STAT3 phosphorylation indicating some degree of leptin resistance in skeletal muscle, which can be explained, at least in part, by an elevation of PTP1B protein content in the vastus lateralis muscle.

To determine if the muscle signalling response to a 30 s all-out sprint exercise is modulated by the exercise mode and the endocrine response, 27 healthy volunteers were divided in 2 groups that performed isokinetic (10 men and 5 women) and isoinertial (7 men and 5 women) Wingate tests. Blood samples and vastus lateralis muscle biopsies were taken before, immediately after, 30 and 120 min after the sprints. Groups were comparable in age, height, body weight, percentage of body fat, peak power per kg of lower extremities lean mass (Pmax) and muscle fibre types. However, the isoinertial group achieved a 25% greater mean power (Pmean). Sprint exercise elicited marked increases in the musculus vastus lateralis AMPKα, ACCβ, STAT3, STAT5 and ERK1/2 phosphorylation (all P<0.05). The AMPKα, STAT3, and ERK1/2 phosphorylation responses were more marked after the isoinertial than isokinetic test (interaction: P<0.01). The differences in muscle signalling could not be accounted for by differences in Pmax, although Pmean could explain part of the difference in AMPKα phosphorylation. The leptin, insulin, glucose, GH, IL-6, and lactate response were similar in both groups. In conclusion, the muscle signalling response to sprint exercise differs between isoinertial and isokinetic sprints., (© Georg Thieme Verlag KG Stuttgart · New York.)

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.