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Leigh M. Vanderloo, Jonathan L. Maguire, David W. H. Dai, Patricia C. Parkin, Cornelia M. Borkhoff, Mark S. Tremblay, Laura N. Anderson, Catherine S. Birken and on behalf of the TARGet Kids! Collaboration

Background: This study aimed to examine the association between physical activity (PA) and a total cardio metabolic risk (CMR) score in children aged 3–12 years. Secondary objectives were to examine the association between PA and individual CMR factors. Methods: A longitudinal study with repeated measures was conducted with participants from a large primary care practice-based research network in Toronto, Canada. Mixed effects models were used to examine the relationship between parent-reported physical activity and outcome variables (total CMR score, triglycerides, glucose, high-density lipoprotein cholesterol, systolic blood pressure, waist circumference, weight-to-height ratio, and non-high-density lipoprotein cholesterol). Results: Data from 1885 children (6.06 y, 54.4% male) with multiple visits (n = 2670) were included in the analyses. For every unit increase of 60 minutes of PA, there was no evidence of an association with total CMR score (adjusted: −0.02 [−0.014 to 0.004], P = .11]. For the individual CMR components, there was evidence of a weak association between PA and systolic blood pressure (−0.01 [−0.03 to −0.01], P < .001) and waist-to-height ratio (−0.81 [−1.62 to −0.003], P < .001). Conclusion: Parent-reported PA among children aged 3–12 years was not statistically associated with total CMR, but was weakly associated with systolic blood pressure and waist-to-height ratio.

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Jill Whitall, Farid Bardid, Nancy Getchell, Melissa M. Pangelinan, Leah E. Robinson, Nadja Schott and Jane E. Clark

In Part I of this series I, we looked back at the 20th century and re-examined the history of Motor Development research described in Clark & Whitall’s 1989 paper “What is Motor Development? The Lessons of History”. We now move to the 21st century, where the trajectories of developmental research have evolved in focus, branched in scope, and diverged into three new areas. These have progressed to be independent research areas, co-existing in time. We posit that the research focus on Dynamical Systems at the end of the 20th century has evolved into a Developmental Systems approach in the 21st century. Additionally, the focus on brain imaging and the neural basis of movement have resulted in a new approach, which we entitled Developmental Motor Neuroscience. Finally, as the world-wide obesity epidemic identified in the 1990s threatened to become a public health crisis, researchers in the field responded by examining the role of motor development in physical activity and health-related outcomes; we refer to this research area as the Developmental Health approach. The glue that holds these research areas together is their focus on movement behavior as it changes across the lifespan.

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Carley O’Neill and Shilpa Dogra

Background: Low- and moderate-intensity exercise training has been shown to be effective for reducing general anxiety and anxiety sensitivity among adults with asthma. Exercise frequency and intensity have been shown to play an integral role in reducing anxiety sensitivity; however, less is known about the impact of high-intensity interval training (HIIT) on anxiety in adults with asthma. Methods: A 6-week HIIT intervention was conducted with adults with asthma. Participants completed HIIT (10% peak power output for 1 min, 90% peak power output for 1 min, repeated 10 times) 3 times per week on a cycle ergometer. Preintervention and postintervention assessments included the Anxiety Sensitivity Index-3 and the Body Sensations Questionnaire. Results: Total Anxiety Sensitivity Index-3 (PRE: 17.9 [11.8]; POST 12.4 [13], P = .002, Cohen d = 0.4, n = 20) and Body Sensations Questionnaire (PRE: 2.4 [1.0]; POST: 2.0 [0.8], P = .007, Cohen d = 0.3) improved from preintervention to postintervention. Conclusion: A 6-week HIIT intervention leads to improved anxiety among adults with asthma. Future research should determine the impact of HIIT among adults with asthma with clinical anxiety.

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Nicolas Aguilar-Farias, Sebastian Miranda-Marquez, Pia Martino-Fuentealba, Kabir P. Sadarangani, Damian Chandia-Poblete, Camila Mella-Garcia, Jaime Carcamo-Oyarzun, Carlos Cristi-Montero, Fernando Rodriguez-Rodriguez, Pedro Delgado-Floody, Astrid Von Oetinger, Teresa Balboa-Castillo, Sebastian Peña, Cristobal Cuadrado, Paula Bedregal, Carlos Celis-Morales, Antonio Garcia-Hermoso and Andrea Cortínez-O’Ryan

Background: The study summarizes the findings of the 2018 Chilean Report Card (RC) on Physical Activity (PA) for Children and Adolescents and compares the results with the first Chilean RC and with other countries from the Global Matrix 3.0. Methods: A Research Work Group using a standardized methodology from the Global Matrix 3.0 awarded grades for 13 PA-related indicators based on the percentage of compliance for defined benchmarks. Different public data sets, government reports, and papers informed the indicators. Results: The grades assigned were for (1) “behaviors that contribute to overall PA levels”: overall PA, D−; organized sport participation, D−; active play, INC; and active transportation, F; (2) “factors associated with cardiometabolic risk”: sedentary behavior, C−; overweight and obesity, F; fitness, D; sleep, INC; and (3) “factors that influence PA”: family and peers, F; school, D; inclusion, INC; community and built environment, B; government strategies and investments, B−. Conclusions: Chile’s grades remained low compared with the first RC. On the positive side, Chile is advancing in environmental and policy aspects. Our findings indicate that the implementation of new strategies should be developed through collaboration between different sectors to maximize effective investments for increasing PA and decreasing sedentary time among children and adolescents in Chile.

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Alex M. Ehlert, Hannah M. Twiddy and Patrick B. Wilson

Caffeine ingestion can improve performance across a variety of exercise modalities but can also elicit negative side effects in some individuals. Thus, there is a growing interest in the use of caffeine mouth rinse solutions to improve sport and exercise performance while minimizing caffeine’s potentially adverse effects. Mouth rinse protocols involve swilling a solution within the oral cavity for a short time (e.g., 5–10 s) before expectorating it to avoid systemic absorption. This is believed to improve performance via activation of taste receptors and stimulation of the central nervous system. Although reviews of the literature indicate that carbohydrate mouth rinsing can improve exercise performance in some situations, there has been no attempt to systematically review the available literature on caffeine mouth rinsing and its effects on exercise performance. To fill this gap, a systematic literature search of three databases (PubMed, SPORTDiscus, and Web of Science) was conducted by two independent reviewers. The search resulted in 11 randomized crossover studies that were appraised and reviewed. Three studies found significant positive effects of caffeine mouth rinsing on exercise performance, whereas the remaining eight found no improvements or only suggestive benefits. The mixed results may be due to heterogeneity in the methods across studies, interindividual differences in bitter tasting, and differences in the concentrations of caffeine solutions. Future studies should evaluate how manipulating the concentration of caffeine solutions, habitual caffeine intake, and genetic modifiers of bitter taste influence the efficacy of caffeine mouth rinsing as an ergogenic strategy.

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Luana Siqueira Andrade, Stephanie Santana Pinto, Mariana Ribeiro Silva, Paula Carolini Campelo, Samara Nickel Rodrigues, Mariana Borba Gomes, Vitor Lima Krüger, Graciele Ferreira de Ferreira and Cristine Lima Alberton

Background: The purpose of this study was to investigate the effects of 2 water-based aerobic training programs on functional capacity and quality of life (QoL) of older women. Design: Randomized clinical trial. Methods: A total of 41 women (64.3 [3.1] y) were randomized into a continuous (CTG) and an interval (ITG) water-based aerobic training group. Training programs were performed with exercise intensity based on rating of perceived exertion throughout 12 weeks (twice a week). Functional tests with and without dual-task and QoL questionnaire were applied pretraining and posttraining. Per protocol and intention to treat analysis were conducted using generalized estimating equations, with Bonferroni post hoc test (α = .05). Results: The per protocol analysis showed an increase in the 30-second chair stand (6% [12%] vs 18% [13%]), 6-minute walk (4% [7%] vs 2% [8%]), and 5-m habitual gait velocity (6% [11%] vs 4% [7%]) tests after CTG and ITG training groups. In addition, the intention to treat analysis revealed an increase in the 30-second chair stand test (7% [13%] vs 12% [13%]) and physical domain of QoL (8% [26%] vs 14% [22%]) after CTG and ITG training groups, as well as an increase in the gait velocity with verbal task after CTG (6% [11%]). Conclusions: Both water-based aerobic training programs induced similar improvements in the functional capacity and maintained the QoL perception in older women.

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Rodrigo dos Santos Guimarães, Alcides Correa de Morais Junior, Raquel Machado Schincaglia, Bryan Saunders, Gustavo Duarte Pimentel and João Felipe Mota

Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. −0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. −1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.

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Sarah A. Roelker, Elena J. Caruthers, Rachel K. Hall, Nicholas C. Pelz, Ajit M.W. Chaudhari and Robert A. Siston

Two optimization techniques, static optimization (SO) and computed muscle control (CMC), are often used in OpenSim to estimate the muscle activations and forces responsible for movement. Although differences between SO and CMC muscle function have been reported, the accuracy of each technique and the combined effect of optimization and model choice on simulated muscle function is unclear. The purpose of this study was to quantitatively compare the SO and CMC estimates of muscle activations and forces during gait with the experimental data in the Gait2392 and Full Body Running models. In OpenSim (version 3.1), muscle function during gait was estimated using SO and CMC in 6 subjects in each model and validated against experimental muscle activations and joint torques. Experimental and simulated activation agreement was sensitive to optimization technique for the soleus and tibialis anterior. Knee extension torque error was greater with CMC than SO. Muscle forces, activations, and co-contraction indices tended to be higher with CMC and more sensitive to model choice. CMC’s inclusion of passive muscle forces, muscle activation-contraction dynamics, and a proportional-derivative controller to track kinematics contributes to these differences. Model and optimization technique choices should be validated using experimental activations collected simultaneously with the data used to generate the simulation.

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Thorben Hülsdünker, Martin Ostermann and Andreas Mierau

Although neural visual processes play a crucial role in sport, experiments have been restricted to laboratory conditions lacking ecological validity. Therefore, this study examined the feasibility of measuring visual evoked potentials in a sport-specific visuomotor task. A total of 18 international elite young table tennis athletes (mean age 12.5 years) performed a computer-based and a sport-specific visuomotor reaction task in response to radial motion-onset stimuli on a computer screen and table tennis balls played by a ball machine, respectively. A 64-channel electroencephalography system identified the N2 and N2-r motion-onset visual evoked potentials in the motion-sensitive midtemporal visual area. Visual evoked potential amplitudes were highly correlated between conditions (N2 r = .72, N2-r r = .74) although significantly lower in the sport-specific task than in the lab-based task (N2 p < .001, N2-r p < .001). The results suggest that sport-specific visual stimulation is feasible to evoke visual potentials. This emphasizes the investigation of visual processes under more ecologically valid conditions in sport and exercise science.

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Sathvik Namburar, William Checkley, Oscar Flores-Flores, Karina M. Romero, Katherine Tomaino Fraser, Nadia N. Hansel, Suzanne L. Pollard and GASP Study Investigators

Background: The authors sought to examine physical activity patterns among children with and without asthma in 2 peri-urban communities in Lima, Peru, to identify socioeconomic and demographic risk factors for physical inactivity and examine the relationship between asthma and physical activity. Methods: The authors measured mean steps per day in 114 children (49 with asthma and 65 without) using pedometers worn over a 1-week period. They also used the 3-day physical activity recall to determine the most common activities carried out by children. Results: The authors found that 84.2% of the children did not meet the daily international physical activity recommendations. Girls took significantly fewer mean steps per day as compared with boys (2258 fewer steps, 95% confidence interval, 1042–3474), but no other factors, including asthma status, showed significant differences in the mean daily steps. Mean daily steps were positively associated with higher socioeconomic status among girls, and current asthma had a larger inverse effect on daily steps in boys when compared with girls. Conclusion: Physical activity levels were below recommended guidelines in all children. There is a need for policy and neighborhood-level interventions to address low physical activity levels among Peruvian youth. Special focus should be given to increasing the physical activity levels in girls.