Exploring factors of adherence to weight loss interventions in population with overweight/obesity: an umbrella review.

Adherence is key for achieving the optimal benefits from a weight loss intervention. Despite the number of studies on factors that promote adherence, their findings suggest inconsistent and fragmented evidence. The aim of this study was to review the existing factors of adherence to weight loss interventions and to find factors that facilitate the design of effective intervention programs. Six databases were searched for this umbrella review; after the screening process, 21 studies were included. A total of 47 factors were identified in six groups as relevant for adherence: (i) sociodemographic (n = 7), (ii) physical activity (n = 2), (iii) dietary (n = 8), (iv) behavioral (n = 4), (v) pharmacological (n = 3), and (vi) multi-intervention (n = 23). In addition, a map of adherence factors was created. The main findings are that with respect to demographic factors, the development of personalized intervention strategies based on the characteristics of specific populations is encouraged. Moreover, self-monitoring has been shown to be effective in behavioral, dietary, and multi-interventions, while technology has shown potential in dietary, behavioral, and multi-interventions. In addition, multi-interventions are adherence-promoting strategies, although more evidence is required on adherence to pharmacological interventions. Overall, the factor map can be controlled and modified by researchers and practitioners to improve adherence to weight loss interventions.

Efficacy of Split Versus Full-Body Resistance Training on Strength and Muscle Growth: A Systematic Review With Meta-Analysis.

ABSTRACT: Ramos-Campo, DJ, Benito-Peinado, PJ, Caravaca, LA, Rojo-Tirado, MA, and Rubio-Arias, JÁ. Efficacy of split versus full-body resistance training on strength and muscle growth: a systematic review with meta-analysis. J Strength Cond Res 38(7): 1330-1340, 2024-No previous study has systematically compared the effect of 2 resistance training routines commonly used to increase muscle mass and strength (i.e., split [Sp] and full-body [FB] routines). Our objective was to conduct a systematic review and meta-analysis following PRISMA guidelines to compare the effects on strength gains and muscle growth in healthy adults. 14 studies (392 subjects) that compared Sp and FB routines in terms of strength adaptations and muscle growth were included. Regarding the effects of the Sp or FB routine on both bench press and lower limbs strength, the magnitude of the change produced by both routines was similar (bench press: mean difference [MD] = 1.19; [-1.28, 3.65]; p = 0.34; k = 14; lower limb: MD = 2.47; [-2.11, 7.05]; p = 0.29; k = 14). Concerning the effect of the Sp vs. FB routine on muscle growth, similar effects were observed after both routines in the cross-sectional area of the elbow extensors (MD = 0.30; [-2.65, 3.24]; p = 0.84; k = 4), elbow flexors (MD = 0.17; [-2.54, 2.88]; p = 0.91; k = 5), vastus lateralis (MD = -0.08; [-1.82, 1.66]; p = 0.93; k = 5), or lean body mass (MD = -0.07; [-1.59, 1.44]; p = 0.92; k = 6). In conclusion, the present systematic review and meta-analysis provides solid evidence that the use of Sp or FB routines within a resistance training program does not significantly impact either strength gains or muscle hypertrophy when volume is equated. Consequently, individuals are free to confidently select a resistance training routine based on their personal preferences.

The real bacterial filtration efficiency to evaluate the effective protection of facemasks used for the prevention of respiratory diseases.

The real protection offered by facemasks to control the transmission of respiratory viruses is still undetermined. Most of the manufacturing regulations, as well as scientific studies, have focused on studying the filtration capacity of the fabrics from which they are made, ignoring the air that escapes through the facial misalignments, and which depends on the respiratory frequencies and volumes. The objective of this work was to define a Real Bacterial Filtration Efficiency for each type of facemask, considering the bacterial filtration efficiency of the manufacturers and the air that passes through them. Nine different facemasks were tested on a mannequin with three gas analyzers (measuring inlet, outlet, and leak volumes) inside a polymethylmethacrylate box. In addition, the differential pressure was measured to determine the resistance offered by the facemasks during the inhalation and exhalation processes. Air was introduced with a manual syringe for 180 s simulating inhalations and exhalations at rest, light, moderate and vigorous activities (10, 60, 80 and 120 L/min, respectively). Statistical analysis showed that practically half of the air entering to the system is not filtered by the facemasks in all intensities (p < 0.001, ηp2 = 0.971). They also showed that the hygienic facemasks filter more than 70% of the air, and their filtration does not depend on the simulated intensity, while the rest of the facemasks show an evidently different response, influenced by the amount of air mobilized. Therefore, the Real Bacterial Filtration Efficiency can be calculated as a modulation of the Bacterial Filtration Efficiencies that depends on the type of facemask. The real filtration capacity of the facemasks has been overestimated during last years since the filtration of the fabrics is not the real filtration when the facemask is worn.

Effect of Menstrual Cycle Phase on the Recovery Process of High-Intensity Interval Exercise-A Cross-Sectional Observational Study.

Although the study of the menstrual cycle influence on endurance exercise has recently increased, there is a lack of literature studying its influence on females' cardiorespiratory recovery. Thus, the aim of the present work was to assess menstrual cycle influence on post-exercise recovery following a high intensity interval exercise in trained females. Thirteen eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early follicular phase (EFP), late follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed (vVO2peak) with a 90-s rest between bouts and a final 5-min active recovery at 30% vVO2peak. All variables were averaged every 15 s, obtaining 19 moments during recovery (time factor). To analyze the effects of the menstrual cycle on the final active cardiorespiratory recovery, an ANOVA for repeated measures was performed. ANOVA showed an effect on menstrual cycle phase on ventilation (EFP: 1.27 ± 0.35; LFP: 1.19 ± 0.36; MLP: 1.27 ± 0.37), breathing frequency (EFP: 35.14 ± 7.14; LFP: 36.32 ± 7.11; MLP: 37.62 ± 7.23), and carbon dioxide production (EFP: 1120.46 ± 137.62; LFP: 1079.50 ± 129.57; MLP: 1148.78 ± 107.91). Regarding the interaction results (phase x time), ventilation is higher at many of the recovery times during the MLP, with less frequent differences between EFP and LFP (F = 1.586; p = 0.019), while breathing reserve is lower at many of the recovery times during MLP, with less time differences between EFP and LFP (F = 1.643; p = 0.013). It seems that the menstrual cycle affects post-exercise recovery specially during the MLP, rising ventilation and lowering breathing reserve, giving rise to an impaired ventilatory efficiency.

Influence of oral contraceptive phase on cardiorespiratory response to exercise in endurance-trained athletes.

OBJECTIVE: The aim of the study was to analyse the cardiorespiratory response to exercise during an oral contraceptive (OC) cycle in endurance-trained women. METHODS: Sixteen low-dose monophasic OC pill (OCP) users performed an interval-running protocol. The protocol consisted of eight 3 min bouts at 85% of participants' maximal aerobic speed (vV̇o2peak) with a 90s recovery at 30% vV̇o2peak in two OC phases: a withdrawal phase (WP) and an active pill phase (APP). The non-parametric Wilcoxon test was applied to analyse differences (p < 0.05) in performance variables between OC cycle phases. RESULTS: Throughout the high-intensity intervals, higher ventilation (WP 80.90 ± 11.49 L/min, APP 83.10 ± 13.33 L/min; p < 0.001) and relative perceived exertion (WP 14.51 ± 2.58, APP 15.11 ± 3.11; p = 0.001) during the APP were found, whereas carbon dioxide production (WP 2040.92 ± 262.93 mL/min, APP 2010.25 ± 305.68 mL/min; p = 0.003) was higher in the WP. During the active recovery intervals, ventilation (WP 65.78 ± 9.90 L/min, APP 67.88 ± 12.66 L/min; p < 0.001) was higher in the APP, while heart rate (WP 159.93 ± 10.26 bpm, APP 159.74 ± 12.83 bpm; p = 0.029) was higher in the WP. CONCLUSION: An increase in ventilation occurs during the APP, which is accompanied by higher perceived exertion. Therefore, coaches and athletes should be aware of these variations, especially perceived exertion, in regard to women's training programmes, in order to improve their performance, wellness and adherence to physical activity.

Cardiorespiratory response to high intensity interval exercise inendurance-trained postmenopausal women

Objetivo: Analizar la respuesta cardiorrespiratoria en mujeres deportistas postmenopáusicas y compararla con la de las eumenorreicas. Material y método: Veintiuna mujeres eumenorreicas (30,5±6,5 años, 58,4±8,7 kg, 25,2±6,7% masa grasa, 48,4±4,4 ml/kg/min V̇O2peak) y trece postmenopáusicas (51,3±3,6 años, 54,1±4,1 kg, 24,2±5,2% masa grasa, 46,01±9,8 ml/kg/min V̇O2peak) entrenadas realizaron un protocolo de interválico de alta intensidad. Éste consistió en 8 series de 3 minutos al 85% con descansos de 90 segundos al 30% de su velocidad aeróbica máxima. Las mujeres eumenorreicas realizaron el protocolo en su fase folicular temprana. Las variables cardiorrespiratorias fueron constantemente monitorizadas a lo largo del protocolo. Resultados: El test de U Mann-Whitney mostró que la respuesta cardiorrespiratoria en el protocolo interválico fue menor en las mujeres postmenopáusicas comparado con las eumenorreicas para la ventilación (66,9±10,1 vs 78,6±11,1 l/min; p<0,001), consumo de oxígeno (33,7±3,9 vs 38,6±4,1 ml/kg/min; p<0,001), porcentaje del consumo máximo de oxígeno (79,6±5,3 vs 76,0±10,6 %; p=0,003), frecuencia cardiaca (154,6±9,5 vs 167,3±11,4 lpm; p<0,001) y producción de dióxido de carbono (1914.8±248,9 vs 2127,5±296,8 ml/min; p<0,001). Por el contrario, el porcentaje de la máxima producción de dióxido de carbono (60.6±15.0 vs 65,3±8,9 %; p=0,010), cociente respiratorio (1,03±0,08 vs 0,96±0,06; p<0,001) y el porcentaje del máximo cociente respiratorio (75,4±19,0 vs 83,3±8,2 %; p<0,001) fue mayor en el grupo de postmenopáusicas. Por último, el porcentaje de la frecuencia cardiaca máxima (91,9±1,7 vs 91,1±2,4 %, p=0,443) y el porcentaje de la ventilación máxima (71,9±6,7 vs 71,1±8,4 %, p=0,138) no mostraron diferencias entre grupos.(AU)

Objectives: To evaluate the cardiorespiratory response to high-intensity interval exercise in endurance-trained postmeno­pausal women and compare it with their counterparts eumenorrheic females. Material and method: Twenty-one eumenorrheic (30.5±6.5 years, 58.4±8.7 kg, 25.2±6.7% fat mass, 48.4±4.4 ml/kg/min V̇O2peak) and thirteen postmenopausal (51.3±3.6 years, 54.1±4.1 kg, 24.2±5.2% fat mass, 46.01±9.8 ml/kg/min V̇O2peak) endurance-trained women performed a high-intensity interval running protocol consisted of 8 bouts of 3-min at 85% with 90-s recovery at 30% of their maximal aerobic speed. It was carried out in the early-follicular phase for the eumenorrheic group and at any time for the postmenopausal group. Cardiorespiratory variables were continuously monitored throughout the protocol. Results: The Mann–Whitney U test reported lower values in postmenopausal women compared to eumenorrheic females for ventilation (66.9±10.1 vs 78.6±11.1 l/min; p<0.001), oxygen consumption (33.7±3.9 vs 38.6±4.1 ml/kg/min; p<0.001), % maximal oxygen consumption (79.6±5.3 vs 76.0±10.6 %; p=0.003), heart rate (154.6±9.5 vs 167.3±11.4 bpm; p<0.001) and carbon dioxide production (1914.8±248.9 vs 2127.5±296.8 ml/min; p<0.001). On the contrary, % maximal carbon dioxide production (60.6±15.0 vs 65.3±8.9 %; p=0.010), respiratory exchange ratio (1.03±0.08 vs 0.96±0.06; p<0.001) and % maximal respiratory exchange ratio (75.4±19.0 vs 83.3±8.2 %; p<0.001) were higher in the postmenopausal group. Finally, % maximal heart rate (91.9±1.7 vs 91.1±2.4 %, p=0.443) and % maximal ventilation (71.9±6.7 vs 71.1±8.4 %, p=0.138) lacked of difference between study groups.(AU)

Effect of Different Types of Face Masks on the Ventilatory and Cardiovascular Response to Maximal-Intensity Exercise.

The development of new models of face masks makes it necessary to compare their impact on exercise. Therefore, the aim of this work was to compare the cardiopulmonary response to a maximal incremental test, perceived ventilation, exertion, and comfort using FFP2 or Emotion masks in young female athletes. Thirteen healthy sportswomen (22.08 ± 1.75 years) performed a spirometry, and a graded exercise test on a treadmill, with a JAEGER® Vyntus CPX gas analyzer using an ergospirometry mask (ErgoMask) or wearing the FFP2 or the Emotion mask below the ErgoMask, randomized on 3 consecutive days. Also, menstrual cycle status was monitored to avoid possible intrasubject alterations. The results showed lower values for the ErgoMask+FFP2, compared to ErgoMask or ErgoMask+Emotion, in forced vital capacity (3.8 ± 0.2, 4.5 ± 0.2 and 4.1 ± 0.1 l, respectively); forced expiratory volume in 1 s (3.3 ± 0.2, 3.7 ± 0.2 and 3.5 ± 0.1 l); ventilation (40.9 ± 1.5, 50.6 ± 1.5 and 46.9 ± 1.2 l/min); breathing frequency (32.7 ± 1.1, 37.4 ± 1.1 and 35.3 ± 1.4 bpm); VE/VO2 (30.5 ± 0.7, 34.6 ± 0.9 and 33.6 ± 0.7); VE/VCO2 (32.2 ± 0.6, 36.2 ± 0.9 and 34.4 ± 0.7) and time to exhaustion (492.4 ± 9.7, 521.7 ± 8.6 and 520.1 ± 9.5 s) and higher values in inspiratory time (0.99 ± 0.04, 0.82 ± 0.03 and 0.88 ± 0.03 s). In conclusion, in young healthy female athletes, the Emotion showed better preservation of cardiopulmonary responses than the FFP2.

Methodological Approach of the Iron and Muscular Damage: Female Metabolism and Menstrual Cycle during Exercise Project (IronFEMME Study).

Background: The increase in exercise levels in the last few years among professional and recreational female athletes has led to an increased scientific interest about sports health and performance in the female athlete population. The purpose of the IronFEMME Study described in this protocol article is to determine the influence of different hormonal profiles on iron metabolism in response to endurance exercise, and the main markers of muscle damage in response to resistance exercise; both in eumenorrheic, oral contraceptive (OC) users and postmenopausal well-trained women. Methods: This project is an observational controlled randomized counterbalanced study. One hundered and four (104) active and healthy women were selected to participate in the IronFEMME Study, 57 of which were eumenorrheic, 31 OC users and 16 postmenopausal. The project consisted of two sections carried out at the same time: iron metabolism (study I) and muscle damage (study II). For the study I, the exercise protocol consisted of an interval running test (eight bouts of 3 min at 85% of the maximal aerobic speed), whereas the study II protocol was an eccentric-based resistance exercise protocol (10 sets of 10 repetitions of plate-loaded barbell parallel back squats at 60% of their one repetition maximum (1RM) with 2 min of recovery between sets). In both studies, eumenorrheic participants were evaluated at three specific moments of the menstrual cycle: early-follicular phase, late-follicular phase and mid-luteal phase; OC users performed the trial at two moments: withdrawal phase and active pill phase. Lastly, postmenopausal women were only tested once, since their hormonal status does not fluctuate. The three-step method was used to verify the menstrual cycle phase: calendar counting, blood test confirmation, and urine-based ovulation kits. Blood samples were obtained to measure sex hormones, iron metabolism parameters, and muscle damage related markers. Discussion: IronFEMME Study has been designed to increase the knowledge regarding the influence of sex hormones on some aspects of the exercise-related female physiology. Iron metabolism and exercise-induced muscle damage will be studied considering the different reproductive status present throughout well-trained females' lifespan.

Body Composition Changes after a Weight Loss Intervention: A 3-Year Follow-Up Study.

Studies comparing different types of exercise-based interventions have not shown a consistent effect of training on long-term weight maintenance. The aim of this study was to compare the effects of exercise modalities combined with diet intervention on body composition immediately after intervention and at 3 years' follow-up in overweight and obese adults. Two-hundred thirty-nine people (107 men) participated in a 6-month diet and exercise-based intervention, split into four randomly assigned groups: strength group (S), endurance group (E), combined strength and endurance group (SE), and control group (C). The body composition measurements took place on the first week before the start of training and after 22 weeks of training. In addition, a third measurement took place 3 years after the intervention period. A significant interaction effect (group × time) (p = 0.017) was observed for the fat mass percentage. It significantly decreased by 5.48 ± 0.65%, 5.30 ± 0.65%, 7.04 ± 0.72%, and 4.86 ± 0.65% at post-intervention for S, E, SE, and C, respectively. Three years after the intervention, the fat mass percentage returned to values similar to the baseline, except for the combined strength and endurance group, where it remained lower than the value at pre-intervention (p < 0.05). However, no significant interaction was discovered for the rest of the studied outcomes, neither at post-intervention nor 3 years later. The combined strength and endurance group was the only group that achieved lower levels of fat mass (%) at both post-intervention and 3 years after intervention, in comparison with the other groups.

Hepcidin response to interval running exercise is not affected by oral contraceptive phase in endurance-trained women.

The use of oral contraceptives (OCs) by female athletes may lead to improved iron status, possibly through the regulation of hepcidin by sex hormones. The present work investigates the response of hepcidin and interleukin-6 (IL-6) to an interval exercise in both phases of the OC cycle. Sixteen endurance-trained OC users (age 25.3 ± 4.7 years; height 162.4 ± 5.7 cm; body mass 56.0 ± 5.7 kg; body fat percentage 24.8 ± 6.0%; peak oxygen consumption [VO2peak ]: 47.4 ± 5.5 mL min-1 kg-1 ) followed an identical interval running protocol during the withdrawal and active pill phases of the OC cycle. This protocol consisted of 8 × 3 minutes bouts at 85% VO2peak speed with 90 seconds recovery intervals. Blood samples were collected pre-exercise, and at 0 hour, 3 hours, and 24 hours post-exercise. Pre-exercise 17ß-estradiol was lower (P = .001) during the active pill than the withdrawal phase (7.91 ± 1.81 vs 29.36 ± 6.45 pg/mL [mean ± SEM]). No differences were seen between the OC phases with respect to hepcidin or IL-6 concentrations, whether taking all time points together or separately. However, within the withdrawal phase, hepcidin concentrations were higher at 3 hours post-exercise (3.33 ± 0.95 nmol/L) than at pre-exercise (1.04 ± 0.20 nmol/L; P = .005) and 0 hour post-exercise (1.41 ± 0.38 nmol/L; P = .045). Within both OC phases, IL-6 was higher at 0 hour post-exercise than at any other time point (P < .05). Similar trends in hepcidin and IL-6 concentrations were seen at the different time points during both OC phases. OC use led to low 17ß-estradiol concentrations during the active pill phase but did not affect hepcidin. This does not, however, rule out estradiol affecting hepcidin levels.

Indirect Markers of Muscle Damage Throughout the Menstrual Cycle.

CONTEXT: The indirect markers of muscle damage have been previously studied in females. However, inconclusive results have been found, possibly explained by the heterogeneity regarding monitoring and verification of menstrual-cycle phase. PURPOSE: To determine whether the fluctuations in sex hormones during the menstrual cycle influence muscle damage. METHODS: A total of 19 well-trained eumenorrheic women (age 28.6 [5.9] y; height 163.4 [6.1] cm; weight 59.6 [5.8] kg body mass) performed an eccentric-based resistance protocol consisting of 10 × 10 back squats at 60% of their 1-repetition maximum on the early follicular phase (EFP), late follicular phase, and midluteal phase of the menstrual cycle. Range of motion, muscle soreness, countermovement jump, and limb circumferences were evaluated prior to 24 and 48 hours postexercise. Perceived exertion was evaluated after each set. RESULTS: Differences in sex hormones indicated that tests were adequately performed in the different menstrual-cycle phases. Prior to exercise, muscle soreness was higher in the EFP (4.7 [7.7]) than in the late follicular phase (1.1 [3.2]; P = .045). No other variables showed significant differences between phases. Time-point differences (baseline, 24, and 48 h) were observed in knee range of motion (P = .02), muscle soreness, countermovement jump, and between sets for perceived exertion (P < .001). CONCLUSION: Although the protocol elicited muscle damage, hormonal fluctuations over the menstrual cycle did not seem to affect indirect markers of muscle damage, except for perceived muscle soreness. Muscle soreness was perceived to be more severe before exercise performed in EFP, when estrogen concentrations are relatively low. This may impair women's predisposition to perform strenuous exercise during EFP.

Strength plus Endurance Training and Individualized Diet Reduce Fat Mass in Overweight Subjects: A Randomized Clinical Trial.

Studies with overweight people are a priority in order to observe the effect of the timing of intervention on pre-obesity people. The aim was to compare different physical activity programs plus an individualized hypocaloric diet on body composition in overweight subjects. A randomized controlled clinical trial was carried out in overweight adults with no history of relevant illness. Primary outcome was total fat mass (TFM). Participants were allocated into four activity programs with equal intensity and volume of exercise for 22 weeks: strength training (S), endurance training (E), strength + endurance training (SE), and 'adhering to physical activity recommendations' (C). Participants followed a diet with 25% less energy (50%-55% carbohydrates, 30%-35% fat) measured by accelerometer. Variables were assessed at baseline and at the end of the intervention. Body composition was measured by dual-energy X-ray absorptiometry. One hundred nineteen from 205 subjects were randomized in the four exercise groups (S = 30/E = 30/SE = 30/C = 29) and 84 participants (36 men/48 women) ended the intervention (S = 19/E = 25/SE = 22/C = 18). At the end of the experiment, all groups except C increased their total physical activity (S = 1159 ± 1740; E = 1625 ± 1790; SE = 1699 ± 2516; C = 724 ± 1979 MET-min/week). Using an ANOVA-test, improvements were observed in body weight (S = -4.6 ± 4.5; E = -6.6 ± 4.6; SE = -8.5 ± 2.8; C = -6.1 ± 5.6 kg, p = 0.059) and TFM (S = -4.24 ± 2.02; E = -4.74 ± 2.96; SE = -6.74 ± 3.27; C = -3.94 ± 4.18%; p < 0.05). The main conclusion was that there were no adverse events. Strength and endurance training with a balanced, individualized hypocaloric diet was the most effective at reducing weight loss and fat mass in overweight subjects. Trial registration: NCT01116856.

The relative age effect on physical fitness in preschool children.

The aim of the present study was to investigate the existence of a relative age effect (RAE) on physical fitness of preschoolers. Anthropometry and physical fitness were assessed in 3147 children (3-5 years old) using the PREFIT battery. Based on the birth year, participants were divided into 3year groups (3-, 4- and 5-years). Within each year group, 4quarter groups were created: quarter 1, preschoolers born from January to March; quarter 2, from April to June; quarter 3, from July to September; quarter 4, from October to December. The MANCOVA analysis revealed a main effect of year group (Wilks' λ = 0.383; F10,5996 = 369.64; p < 0.001, ηp 2 = 0.381) and of quarter (Wilks' λ = 0.874; F15,8276.6 = 27.67; p < 0.001; ηp 2 = 0.044) over the whole battery of tests. To the best of our knowledge, this is the first study to report the existence of RAE at the preschool stage. In general, performance improved as the relative age increased (i.e., those born in quarter 1 performed better than those in the other quarters). Individualization strategies should be addressed within the same academic year not only in elementary or secondary years but also in preschoolers.

A Single Question of Parent-Reported Physical Activity Levels Estimates Objectively Measured Physical Fitness and Body Composition in Preschool Children: The PREFIT Project.

Physical inactivity is recognized as a determinant of low physical fitness and body composition in preschool children, which in turn, are important markers of health through the lifespan. Objective methods to assess physical activity, physical fitness and body composition in preschool children are preferable; however, they have some practical limitations in the school context. Therefore, the aim of this study was to test whether a single question regarding physical activity level of preschool children, reported by their parents, could be used as an alternative screening tool of physical fitness and body composition. The information was obtained from 10 different cities throughout Spain, gathering a total of 3179 healthy preschool children (52.8% boys and 47.2% girls) aged 3-5 years. Physical activity levels of preschool children were reported by parents using a single question with five response options (very low, low, average, high, or very high). Physical fitness and body composition were assessed with the PREFIT fitness battery. The results showed that parents' perception of their children's physical activity was positively associated with all objectively measured physical fitness components (ßrange = -0.094 to 0.113; all p < 0.020); and negatively with body composition indicators as measured (ßrange = -0.113 to -0.058; all p < 0.001). The results showed significant differences in all physical fitness and body composition z-scores across the parent-reported physical activity levels (all p < 0.017 and all p < 0.001, respectively), as well as, for the fitness index (p < 0.001). Our study suggests that in school settings with insufficient resources to objectively assess fitness and body composition, parents-reported physical activity level by means of a single question might provide useful information about these important health markers in preschool children.

Effect of induced alkalosis on performance during a field-simulated BMX cycling competition.

OBJECTIVES: The aim of the present study was to test the effect of sodium bicarbonate (NaHCO3-) ingestion on performance during a simulated competition on a Bicycle Motocross (BMX) track. DESIGN: Double-blind cross-over study. METHODS: Twelve elite male BMX cyclists (age: 19.2±3.4 years; height: 174.2±5.3cm; body mass: 72.4±8.4kg) ingested either NaHCO3- (0.3g.kg-1 body weight) or placebo 90min prior to exercise. The cyclists completed three races in a BMX Olympic track interspersed with 15min of recovery. Blood samples were collected to assess the blood acid-base status. Performance, cardiorespiratory, heart rate variability (HRV) as well as subjective variables were assessed. RESULTS: The main effect of condition (NaHCO3- vs. placebo) was observed in pH, bicarbonate concentration and base excess (p<0.05), with a significant blood alkalosis. No changes were found in time, peak velocity and time to peak velocity for condition (p>0.05). The HRV analysis showed a significant effect of NaHCO3- ingestion, expressed by the rMSSD30 (root mean square of the successive differences) (p<0.001). There was no effect of condition on oxygen uptake, carbon dioxide production, or pulmonary ventilation (p>0.05). Finally, there was no effect of condition for any subjective scale (p>0.05). CONCLUSIONS: We present here the first field condition study to investigate the effect of bicarbonate ingestion over performance in BMX discipline. The results showed that NaHCO3--induced alkalosis did not improve performance in a simulated BMX competition in elite BMX cyclists, although future studies should consider the effects of NaHCO3- on autonomic function as a component of recovery.

Physiological Profile of an Uphill Time Trial in Elite Cyclists.

CONTEXT: While a number of studies have researched road-cycling performance, few have attempted to investigate the physiological response in field conditions. PURPOSE: To describe the physiological and performance profile of an uphill time trial (TT) frequently used in cycling competitions. METHODS: Fourteen elite road cyclists (mean ± SD age 25 ± 6 y, height 174 ± 4.2 cm, body mass 64.4 ± 6.1 kg, fat mass 7.48% ± 2.82%) performed a graded exercise test to exhaustion to determine maximal parameters. They then completed a field-based uphill TT in a 9.2-km first-category mountain pass with a 7.1% slope. Oxygen uptake (VO2), power output, heart rate (HR), lactate concentration, and perceived-exertion variables were measured throughout the field-based test. RESULTS: During the uphill TT, mean power output and velocity were 302 ± 7 W (4.2 ± 0.1 W/kg) and 18.7 ± 1.6 km/h, respectively. Mean VO2 and HR were 61.6 ± 2.0 mL · kg-1 · min-1 and 178 ± 2 beats/min, respectively. Values were significantly affected by the 1st, 2nd, 6th, and final kilometers (P < .05). Lactate concentration and perceived exertion were 10.87 ± 1.12 mmol/L and 19.1 ± 0.1, respectively, at the end of the test, being significantly different from baseline measures. CONCLUSION: The studied uphill TT is performed at 90% of maximum HR and VO2 and 70% of maximum power output. To the authors' knowledge, this is the first study assessing cardiorespiratory parameters combined with measures of performance, perceived exertion, and biochemical variables during a field-based uphill TT in elite cyclists.

Predicting Peak Oxygen Uptake From the 6-Minute Walk Test in Patients With Pulmonary Hypertension.

PURPOSE: To determine whether the 6-minute walk test (6MWT) is a predictor of peak oxygen uptake ((Equation is included in full-text article.)O2) in patients with idiopathic pulmonary arterial hypertension (IPAH). METHODS: A total of 157 patients treated for IPAH completed a 6MWT in accordance with American Thoracic Society standards. Heart rate, pulse oximetry, and Borg rating of perceived exertion were determined at baseline and posttest. A cardiopulmonary exercise test (CPET) was performed on a cycle ergometer using a ramp protocol. Participants were stratified post hoc by age into 3 groups: children (n = 26), adolescents (n = 49), and adults (n = 82). Multiple linear regression analysis was performed to predict peak (Equation is included in full-text article.)O2 from the 6MWT. RESULTS: The regression equation generated for the children was the only model to strongly predict peak (Equation is included in full-text article.)O2 (r = 0.87; P < .001). Similar models for adolescent (r = 0.59; P < .001) and adult groups (r = 0.68; P < .001) did not achieve the same level of correlation. CONCLUSION: Six-Minute Walk Test was able to accurately predict peak (Equation is included in full-text article.)O2 in children (6-12 years) with IPAH; however, the model was weaker for predicting peak (Equation is included in full-text article.)O2 in older populations. These findings suggest that 6MWT may be as valid a test for predicting peak (Equation is included in full-text article.)O2 in children with IPAH as CPET measured peak (Equation is included in full-text article.)O2. In older IPAH populations, CPET is the only reliable method for the evaluation of peak (Equation is included in full-text article.)O2.

Discriminant models to estimate the body weight loss after a six-month long diet and exercise-based intervention.

BACKGROUND: The main concern of the people who follow a weight loss program is the body weight loss, independently of the body composition. The aim of this study was to create a mathematical model able to discriminate the body weight change based on initial body composition variables. METHODS: The study included 239 overweight and obese participants (18-50 years; Body Mass Index (BMI)>25 and <34.9 kg/m2). Participants performed an endrance, strength or a combined endurance and strength training three times per week, or followed the American College of Sports Medicine physical activity guidelines for body weight loss, during twenty-four weeks while having 25-30% caloric restriction. Two multivariate discriminant models were performed taking into account the groups below and above the mean body weight change. RESULTS: The discriminant models obtained could discriminate the body weight change with a 65-70% of correct classification. BW, fat-free mass (FFM), and fat mass (FM) were shown to be the most discriminant variables for the discriminant models. CONCLUSIONS: People having higher FM and FFM at the beginning of an intervention will lose a greater amount of weight until the end of it.

Effects of age, sex, and treatment on weight-loss dynamics in overweight people.

The objective of this work was to evaluate how sex, age, and the kind of treatment followed affect weight loss in overweight men and women, as well as to develop an explanation for the evolution of weight-loss dynamics. The study consisted of 119 overweight participants (18-50 years old, body mass index >25 and <29.9 kg·m(-2)), who were randomly assigned to 1 of 4 treatment programs, namely, strength training (n = 30), endurance training (n = 30), a combination of strength training and endurance training (n = 30), and a careful treatment including diet and physical recommendations (n = 29). Each of the training groups exercised 3 times per week for 24 weeks, and their daily diet was restricted to a specific protocol during the testing period and controlled carefully. Body weight changes in the participants were evaluated every 15 days. Based on this study, we developed and validated different sets of equations to accurately capture the weight-loss dynamics. There were no significant differences in terms of global body weight changes from the statistical viewpoint, either regarding the carried out treatment or the individuals' ages. However, significant differences in weight-loss tendency were found depending on participant sex. We concluded that the effectiveness of different possible treatments for weight loss varies by sex and, based on our experimental observations, a quadratic function provides the most accurate model for capturing specific weight-loss dynamics. This trial is registered at Clinical Trials Gov.: number NCT01116856.

[Sugar and exercise: its importance in athletes]. / El azúcar y el ejercicio físico: su importancia en los deportistas.

Muscle glycogen, the predominant form of stored glucose in the body, and blood glucose are the main energy substrates for muscle contraction during exercise. Sucrose is an ideal substance for athletes to incorporate because it provides both glucose and fructose. Therefore, it is essential that athletes monitor their diet to maintain and increase muscle glycogen deposits, since they are a major limiting factor of prolonged exercise performance. Carbohydrate-rich diets are also recommended for endurance and ultra-endurance exercise, because they are associated with increased muscle glycogen stores, as well as delayed onset of fatigue. In addition, high carbohydrate diets and carbohydrate intake before and during exercise have shown to be beneficial due to increased concentrations of hepatic glycogen and maintenance of blood glucose. The effect of carbohydrate intake on athletic performance mainly depends on the characteristics of the exercise, the type and amount of carbohydrate ingested and the time of intake. A combination of these factors must be taken into account when analysing individual athletic performance.

El glucógeno muscular, principal almacén de glucosa en el organismo, y la glucemia sanguínea constituyen uno de los principales sustratos energéticos para la contracción muscular durante el ejercicio. El azúcar (sacarosa) es un estupendo suplemento al suministrar tanto glucosa como fructosa. Por ello, es esencial que los deportistas cuiden su alimentación, para mantener y aumentar los depósitos de este combustible, ya que las reservas de glucógeno muscular constituyen un factor limitante de la capacidad para realizar ejercicio prolongado. Las dietas ricas en hidratos de carbono se han recomendado para el ejercicio de resistencia y ultraresistencia debido a su relación con el aumento de las reservas musculares de glucógeno y la aparición tardía de la fatiga. Además de las dietas altas en carbohidratos, la ingesta de carbohidratos antes y durante el ejercicio, han demostrado ser beneficiosas debido al aumento de las concentraciones hepáticas de glucógeno y el mantenimiento de las concentraciones de glucosa en sangre. El efecto de la ingesta de carbohidratos sobre el rendimiento deportivo dependerá principalmente de las características del esfuerzo, del tipo y cantidad de carbohidratos ingeridos y del momento de la ingesta. La combinación de todos estos factores debe ser tenida en cuenta a la hora de analizar el rendimiento en las diferentes especialidades deportivas.