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The early identification of speech and language delays is a crucial first step in the effective prevention of developmental and socioemotional problems. Children's early cognitive and language development has bearing on later development and readiness for learning and social competence. The Speech and Language Pathology Early Screening Instrument (SLPESI) was developed to identify possible speech and language delays in 18 to 21-month-old children. The purpose of the present study was to pilot the SLPESI and assess its ability to identify speech and language delays in children of this age group. A total of 252 children, aged 17-23 months, participated in the SLPESI. The test took less than five minutes to administer. Of the 252 children screened, 56 (22%) were recommended for assessment by a Speech and Language Pathologist (S-LP) based on the results of the questionnaire. Of those recommended, 34 came in for assessment and 31 (91%) were assessed and diagnosed with speech and language delays ranging from mild to severe. In order to examine the reliability of the SLPESI, 19 children who passed the initial screening procedure were brought in for a follow-up assessment. Of these, 18 had age-appropriate speech and language skills and one had a mild to moderate speech and language delay. The SLPESI proved to be a quick and effective screening instrument that may help predict speech and language delays in children 18-21 months of age. [ABSTRACT FROM AUTHOR]

Current research on protein supplementation has focused on the effectiveness of post-workout (PWO) consumption of specific proteins and/or amino acids. Further research shows that pwo protein supplementation can significantly increase skeletal muscle protein synthesis and reduce protein breakdown in muscles, especially if intake is timed properly. Whole foods, protein supplements, and amino acid supplements are the primary sources of pwo protein. Most commercially available protein supplements are produced from sources such as milk, egg albumin, soy, wheat, and collagen. This article examines the wide variety of protein sources and proposes a comprehensive guide for strength and conditioning coaches. [ABSTRACT FROM AUTHOR]

Children with lived cancer experience encounter adversity, therefore experiences promoting psychosocial health are necessary. This pilot study determined the impact of recreational oncology camps (ROC) on resilience, hope, social support, and mental well-being in youth who have lived with cancer. Youth (6-18 years) with cancer experience enrolled in an 11-day session of ROC (Muskoka, Ontario, Canada) were invited to participate. Participants completed a survey [Children's Hope Scale (CHS), Child and Youth Resilience Measure (CYRM-R), Social Provisions Scale (SPS-5), and Short Warwick-Edinburgh Mental Wellbeing Scale (SWEMWBS)] on the first (T1) and last day (T2) of camp, and 3 months post-camp (T3). Repeated-measures ANOVAs evaluated differences in survey scores among time points. Ten participants (14.1 ± 2.5 years) were included in the analysis. CHS scores at T3 were lower than T1 and T2 (F = 9.388, p = 0.008). CYRM-R, SPS-5, and SWEMWBS scores were high but did not differ between time points. Hope decreased 3 months post-camp, suggesting a need for continued psychosocial support. Overall, the ROC environment is associated with positive psychosocial health.

Despite exercise intolerance being predictive of outcomes in pulmonary arterial hypertension (PAH), its underlying cardiac mechanisms are not well described. The aim of the study was to explore the biventricular response to exercise and its associations with cardiorespiratory fitness in children with PAH. Participants underwent incremental cardiopulmonary exercise testing and simultaneous exercise echocardiography on a recumbent cycle ergometer. Linear mixed models were used to assess cardiac function variance and associations between cardiac and metabolic parameters during exercise. Eleven participants were included with a mean age of 13.4 ± 2.9 yr old. Right ventricle (RV) systolic pressure (RVsp) increased from a mean of 59 ± 25 mmHg at rest to 130 ± 40 mmHg at peak exercise ( P < 0.001), whereas RV fractional area change (RV-FAC) and RV-free wall longitudinal strain (RVFW-S l ) worsened (35.2 vs. 27%, P = 0.09 and -16.6 vs. -14.6%, P = 0.1, respectively). At low- and moderate-intensity exercise, RVsp was positively associated with stroke volume and O 2 pulse ( P < 0.1). At high-intensity exercise, RV-FAC, RVFW-S l , and left ventricular longitudinal strain were positively associated with oxygen uptake and O 2 pulse ( P < 0.1), whereas stroke volume decreased toward peak ( P = 0.04). In children with PAH, the increase of pulmonary pressure alone does not limit peak exercise, but rather the concomitant reduced RV functional reserve, resulting in RV to pulmonary artery (RV-PA) uncoupling, worsening of interventricular interaction and LV dysfunction. A better mechanistic understanding of PAH exercise physiopathology can inform stress testing and cardiac rehabilitation in this population. NEW & NOTEWORTHY In children with pulmonary arterial hypertension, there is a marked increase in pulmonary artery pressure during physical activity, but this is not the underlying mechanism that limits exercise. Instead, right ventricle-to-pulmonary artery uncoupling occurs at the transition from moderate to high-intensity exercise and correlates with lower peak oxygen uptake. This highlights the more complex underlying pathological responses and the need for multiparametric assessment of cardiac function reserve in these patients when feasible.

The objective of this pilot study was to characterize relationships between skeletal muscle energy metabolism and body composition in healthy adults with varied amounts and distribution of adipose tissue. In vivo muscle energetics were quantified using dynamic 31 P magnetic resonance spectroscopy with knee extension exercise standardized to subject lean body mass. Spearman's correlation analysis examined relationships between muscle metabolism indices and measures of adiposity including body mass index (BMI), total body fat, and quadriceps intermuscular adipose tissue (IMAT). Post hoc partial correlations were examined controlling for additional body composition measures. Kruskal-Wallis tests with Dunn-Sidak post hoc comparisons evaluated group differences in energy metabolism based on body composition profiles (i.e., lean, normal-weight obese, and overweight-obese) and IMAT tertiles. BMI negatively correlated with end-exercise muscle pH after correcting for IMAT and total body fat ( r = -0.46, P = 0.034). Total adiposity negatively correlated with maximum oxidative capacity after correcting for IMAT ( r = -0.54, P = 0.013). IMAT positively correlated with muscle proton buffering capacity after correcting for total body fat ( r = 0.53, P = 0.023). Body composition groups showed differences in end-exercise fall in [PCr] with normalized workload ( P = 0.036; post hoc: overweight-obese < lean, P = 0.029) and maximum oxidative capacity ( P = 0.021; post hoc: normal-weight obese < lean, P = 0.016). IMAT tertiles showed differences in end-exercise fall in [PCr] with normalized workload ( P = 0.035; post hoc: 3rd < 1st, P = 0.047). Taken together, these results support increased adiposity is associated with reduced muscle energetic efficiency with more reliance on glycolysis, and when accompanied with reduced lean mass, is associated with reduced maximum oxidative capacity. NEW & NOTEWORTHY Skeletal muscle energy production is influenced by both lean body mass and adipose tissue but the effect of their distribution on energy metabolism is unclear. This study examined variations in quadriceps muscle energy metabolism in healthy adults with varied relative amounts of lean and adipose tissue. Results suggest increased adiposity is associated with reduced muscle energetic efficiency with more reliance on glycolysis, and when accompanied with reduced lean mass, is associated with reduced maximum oxidative capacity.

Children who experience early life stress demonstrate changes to their stress responses, which may modulate long-term health. Childhood cancer presents significant stress during diagnosis, treatment, and survivorship. We hypothesized that children who have completed chemotherapy treatment for ALL will demonstrate altered hormone patterns in response to a stressor compared with healthy controls. Twelve pediatric ALL survivors and 12 healthy controls completed the Trier Social Stress Test. Salivary samples, heart rate, and self-report ratings of stress were collected at baseline, pretest, and posttest. Between group comparison showed baseline (interleukin [IL]-8) was significantly higher in the survivor group versus controls (survivors: 89.9, 40.1-544.9 pg ml -1 ; controls: 30.7, 5.6-241.9 pg ml -1 , p = .001) as was peak (IL-8) (survivors: 147.1, 71.6-1177.6 pg ml -1 ; controls: 75.5, 28.6-698.6 pg ml -1 ). Peak salivary alpha-amylase (sAA) concentration was significantly lower in the survivor group (survivors: 69.3, 19.4-195.5 U ml -1 ; controls: 91.2, 27.7-213.7 U ml -1 ; p = .04). Repeated measures ANOVA revealed significant main effects for time on cortisol (F (2.35, 50.81)  = 5.9, p < .01), sAA (F (1.56, 33.17)  = 6.6, p < .01), stress ratings (F (3.42, 88.14)  = 53.4, p < .001), and heart rate (F (8, 83)  = 16.8, p < .05). Significant main effects for group were observed for IL-8 (F (1, 23)  = 8.2, p < .01) and tumor necrosis factor-α (F (1, 23)  = 6.8, p < .05). Significant interaction effects for group × time were found for sAA (F (5, 106)  = 2.8, p < .05). Our results indicate that childhood ALL survivors have similar responses to stress as healthy controls, but lower sympatho-adrenal-medullary reactivity. Therefore, altered stress regulation may present a pathway modulating long-term health in this population., (© 2022 Wiley Periodicals LLC.)

Exercise intolerance is a common adverse effect of childhood cancer, contributing to impaired health and well-being. While reduced aerobic fitness has been attributed to central cardiovascular deficiencies, the involvement of peripheral musculature has not been investigated. We studied peripheral muscle function in children following cancer treatment using noninvasive phosphorus-31 magnetic resonance spectroscopy. Ten acute lymphoblastic leukemia (ALL) and 1 lymphoma patient 8 to 18 years of age who completed treatment 6 to 36 months prior and 11 healthy controls participated in the study. Phosphorus-31 magnetic resonance spectroscopy was used to characterize muscle bioenergetics at rest and following an in-magnet knee-extension exercise. Exercise capacity was evaluated using a submaximal graded treadmill test. Both analysis of variance and Cohen d were used as statistical methods to determine the statistical significance and magnitude of differences, respectively, on these parameters between the patient and control groups. The patients treated for ALL and lymphoma exhibited lower anaerobic function ( P =0.14, d =0.72), slower metabolic recovery ( P =0.08, d =0.93), and lower mechanical muscle power ( d =1.09) during exercise compared with healthy controls. Patients demonstrated lower estimated VO 2peak (41.61±5.97 vs. 47.71±9.99 mL/min/kg, P =0.11, d =0.76), lower minutes of physical activity (58.3±35.3 vs. 114.8±79.3 min, P =0.12, d =0.99) and higher minutes of inactivity (107.3±74.0 vs. 43.5±48.3 min, d =1.04, P <0.05). Children treated for ALL and lymphoma exhibit altered peripheral skeletal muscle metabolism during exercise. Both deconditioning and direct effects of chemotherapy likely contribute to exercise intolerance in this population., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Adiposity and mitochondrial dysfunction are related factors contributing to metabolic disease development. This pilot study examined whether in vivo and ex vivo indices of mitochondrial metabolism were differentially associated with body composition in males and females., Methods: Thirty-four participants including 19 females (mean 27 yr) and 15 males (mean 29 yr) had body composition assessed by dual energy x-ray absorptiometry and magnetic resonance (MR) imaging. Monocyte reserve capacity and maximal oxygen consumption rate (OCR) were determined ex vivo using extracellular flux analysis. In vivo quadriceps mitochondrial function was measured using 31 P-MR spectroscopy based on post-exercise recovery kinetics (τPCr). The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated from fasting glucose and insulin levels. Variables were log-transformed, and Pearson correlations and partial correlations were used for analyses., Results: Mitochondrial metabolism was similar between sexes (p > 0.05). In males only, higher fat mass percent (FM%) was correlated with lower reserve capacity (r = - 0.73; p = 0.002) and reduced muscle mitochondrial function (r = 0.58, p = 0.02). Thigh subcutaneous adipose tissue was inversely related to reserve capacity in males (r = - 0.75, p = 0.001), but in females was correlated to higher maximal OCR (r = 0.48, p = 0.046), independent of FM. In females, lean mass was related to greater reserve capacity (r = 0.47, p = 0.04). In all participants, insulin (r = 0.35; p = 0.04) and HOMA-IR (r = 0.34; p = 0.05) were associated with a higher τPCr., Conclusions: These novel findings demonstrate distinct sex-dependent associations between monocyte and skeletal muscle mitochondrial metabolism with body composition. With further study, increased understanding of these relationships may inform sex-specific interventions to improve mitochondrial function and metabolic health., (© 2022. The Author(s).)

Magnetic Resonance Imaging (MRI) is well-suited for imaging peripheral blood flow due to its non-invasive nature and excellent spatial resolution. Although MRI is routinely used in adults to assess physiological changes in chronic diseases, there are currently no MRI-based data quantifying arterial flow in pediatric or adolescent populations during exercise. Therefore the current research sought to document femoral arterial blood flow at rest and following exercise in a pediatric-adolescent population using phase contrast MRI, and to present test-retest reliability data for this method. Ten healthy children and adolescents (4 male; mean age 14.8 ± 2.4 years) completed bloodwork and resting and exercise MRI. Baseline images consisted of PC-MRI of the femoral artery at rest and following a 5 × 30 s of in-magnet exercise. To evaluate test-retest reliability, five participants returned for repeat testing. All participants successfully completed exercise testing in the MRI. Baseline flow demonstrated excellent reliability (ICC = 0.93, p = 0.006), and peak exercise and delta rest-peak flow demonstrated good reliability (peak exercise ICC = 0.89, p = 0.002, delta rest-peak ICC = 0.87, p = 0.003) between-visits. All three flow measurements demonstrated excellent reliability when assessed with coefficients of variance (CV's) (rest: CV = 6.2%; peak exercise: CV = 7.3%; delta rest-peak: CV = 7.1%). The mean bias was small for femoral arterial flow. There was no significant mean bias between femoral artery flow visits 1 and 2 at peak exercise. There were no correlations between age or height and any of the flow measurements. There were no significant differences between male and female participants for any of the flow measurements. The current study determined that peripheral arterial blood flow in children and adolescents can be evaluated using non-invasive phase contrast MRI. The MRI-based techniques that were used in the current study for measuring arterial flow in pediatric and adolescent patients demonstrated acceptable test-retest reliability both at rest and immediately post-exercise., (© 2022 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Exercise intolerance is common in people with CF (pwCF), but not universal among all individuals. While associated with disease prognosis, exercise intolerance is not simply a reflection of the degree of lung disease. In people with severe CF, respiratory limitations may contribute more significantly to impaired exercise capacity than in those with mild-moderate CF. At all levels of disease severity, there are peripheral factors e.g., abnormal macro- and micro-vascular function that impair blood flow and reduce oxygen extraction, and mitochondrial defects that diminish metabolic efficiency. We discuss advances in understanding the central and peripheral mechanisms underlying exercise intolerance in pwCF. Exploring both the central and peripheral factors that contribute to exercise intolerance in CF can help inform the development of new therapeutic targets, as well as help define prognostic criteria., (Copyright © 2021. Published by Elsevier B.V.)

Background: The roles of physical activity (PA) and exercise within the management of cystic fibrosis (CF) are recognised by their inclusion in numerous standards of care and treatment guidelines. However, information is brief, and both PA and exercise as multi-faceted behaviours require extensive stakeholder input when developing and promoting such guidelines., Method: On 30 th June and 1 st July 2021, 39 stakeholders from 11 countries, including researchers, healthcare professionals and patients participated in a virtual conference to agree an evidence-based and informed expert consensus about PA and exercise for people with CF. This consensus presents the agreement across six themes: (i) patient and system centred outcomes, (ii) health benefits, iii) measurement, (iv) prescription, (v) clinical considerations, and (vi) future directions. The consensus was achieved by a stepwise process, involving: (i) written evidence-based synopses; (ii) peer critique of synopses; (iii) oral presentation to consensus group and peer challenge of revised synopses; and (iv) anonymous voting on final proposed synopses for adoption to the consensus statement., Results: The final consensus document includes 24 statements which surpassed the consensus threshold (>80% agreement) out of 30 proposed statements., Conclusion: This consensus can be used to support health promotion by relevant stakeholders for people with CF.

Soccer referees represent a specialized population who are required to perform decisional or perceptual tasks during physical exertion. Recent studies have demonstrated that submaximal acute exercise has a positive impact on cognitive performance. However, less is known about the impact of more strenuous exertion on cognitive performance. This study assessed the effect of moderate and maximal intensity exercise exertion on a cognitive performance in sub-elite soccer referees. Twelve experienced soccer referees (4 female, 8 male) were recruited. Data were collected on 2 separate days. Baseline fitness level was assessed by a standardized aerobic capacity test (VO 2max Test) on Day 1, along with practice trials of the Stroop Color Word Test (Stroop Test) for evaluating cognitive performance. On Day 2, cognitive performance was assessed before, during, and after an incremental intensity exercise protocol based on the Fédération International de Football Association (FIFA) referee fitness test. Relative to results obtained at rest performance on the Stroop Test improved at moderate exertion and at maximal exertion during the modified FIFA fitness test (F = 18.97, p = .005). Mean time to completion (in seconds) of the interference Stroop task significantly improved (p < .05) between rest and moderate exertion [-3.0 ± 3.0 seconds] and between rest and maximal exertion [-4.8 ± 2.6 seconds]. In summary, we observed that cognitive performance was found to improve when sub-elite soccer referees performed moderate and maximal exercise relative to results obtained at rest. It is possible that referees focus their attention to improve goal-oriented processing in the brain during physical exertion., (© Journal of Sports Science and Medicine.)

Stress is a ubiquitous experience that can be adaptive or maladaptive. Physiological stress regulation, or allostasis, can be disrupted at any point along the regulatory pathway resulting in adverse effects for the individual. Children with cancer exhibit significant changes to these pathways in line with stress dysregulation and long-term effects similar to those observed in other early-life stress populations, which are thought to be, in part, a result of cytotoxic cancer treatments. Children with cancer may have disruption to several steps in the stress-regulatory pathway including cognitive-affective function, neurological disruption to stress regulatory brain regions, altered adrenal and endocrine function, and disrupted tissue integrity, as well as lower engagement in positive coping behaviours such as physical activity and pro-social habits. To date, there has been minimal study of stress reactivity patterns in childhood illness populations. Nor has the role of stress regulation in long-term health and function been elucidated. We conclude that consideration of stress regulation in childhood cancer may be crucial in understanding and treating the disease.

Objective: To evaluate the feasibility of studying creatine in juvenile dermatomyositis (JDM). Secondary objectives were to determine the effect of creatine on muscle function and metabolism, aerobic capacity, fatigue, physical activity, and quality of life (QOL), as well as its safety., Methods: We conducted a 6-month, double-blind, randomized, multiple-baseline design; patients were assigned to creatine or placebo. Feasibility was assessed using attended study visits, completed study procedures, and adherence. Muscle function, aerobic capacity, and muscle strength were assessed with standardized exercise tests. Muscle metabolism was assessed using a 31-Phosphorus Magnetic Resonance Spectroscopy protocol. Fatigue, physical activity, and QOL were assessed by questionnaires. Statistical significance was estimated using a randomization (permutation) test. Changes in outcome measures taken at baseline and end-of-study were calculated using paired t -tests., Results: Median (range) adherence to the study drug was 88.5% (20.5-95.5%) and the proportion of subjects with 80% adherence or higher was 76.9%. There were no missed study visits. There were no statistically significant changes in muscle function, strength, aerobic capacity, disease activity, fatigue, physical activity, or QOL while subjects were receiving creatine compared to placebo. There were statistically significant adaptations in muscle metabolism (e.g., decrease in change in muscle pH following exercise, and decrease in phosphate/phosphocreatine ratio) at the end-of-study compared to baseline. There were no significant adverse effects., Conclusion: Creatine supplementation in children with JDM is feasible to study, and is safe and well-tolerated; it may lead to improvements in muscle metabolism., (Copyright © 2021 by the Journal of Rheumatology.)

Massage therapy is a common postexercise muscle recovery modality; however, its mechanisms of efficacy are uncertain. We evaluated the effects of massage on systemic inflammatory responses to exercise and postexercise muscle performance and soreness. In this crossover study, nine healthy male athletes completed a high-intensity intermittent sprint protocol, followed by massage therapy or control condition. Inflammatory markers were assessed pre-exercise; postexercise; and at 1, 2, and 24 h postexercise. Muscle performance was measured by squat and drop jump, and muscle soreness on a Likert scale. Significant time effects were observed for monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), drop jump performance, squat jump performance, and soreness. No significant effects for condition were observed. However, compared with control, inflammatory marker concentrations (IL-8, TNFα, and MCP-1) returned to baseline levels earlier following the massage therapy condition ( p < 0.05 for all). IL-6 returned to baseline levels earlier following the control versus massage therapy condition ( p < 0.05). No differences were observed for performance or soreness variables. MCP-1 area under the curve (AUC) was negatively associated with squat and drop jump performance, while IL-10 AUC was positively associated with drop jump performance ( p < 0.05 for all). In conclusion, massage therapy promotes resolution of systemic inflammatory signaling following exercise but does not appear to improve performance or soreness measurements.

Objective: This study aims to noninvasively quantify blood flow in the uterine arteries (UTAs) and umbilical vein (UV) using phase-contrast magnetic resonance imaging (PC-MRI) and test whether these correlate with maternal fitness parameters., Method: Resting UTA and UV flows were measured in 23 healthy 30 ± 3-year-old women who engaged in moderate-intensity physical activity during pregnancy. Participant fitness was characterized in the second and third trimesters using the submaximal oxygen uptake (VO 2 ) test measuring heart rate (HR), VO 2 , ventilation (ventilatory equivalent [VE]/VO 2 ), and the Borg rating of perceived exertion (respiratory quotient [RQ]). Linear regression models were used to determine the associations between blood flow and maternal fitness measures., Results: Blood flows in the UTA (957 ± 241 mL/min) and UV (132 ± 38 mL/min/kg) were successfully measured in 20 (87%) participants. Neither was associated with any physical fitness parameters (HR, VO 2 , VE/VO 2 , and RQ) nor with any second-to-third trimester change in these parameters., Conclusion: PC-MRI can be used to noninvasively measure blood flow in the UTA and UV. Neither resting UTA nor UV flow is associated with maternal fitness parameters. This is the first MRI-based study to provide novel hemodynamic data suggesting decoupling between maternal moderate fitness level and the maternal-placental-fetal hemodynamic system in healthy, normal body mass index (BMI) pregnancies., (© 2019 John Wiley & Sons, Ltd.)

Haematopoietic stem cell transplant (HSCT) is an intensive therapy for some pediatric hematological illnesses. Survivors are at risk for adverse effects including exercise intolerance. Peripheral tissue dysfunction may contribute to exercise intolerance; therefore, we examined the feasibility of a magnetic resonance spectroscopy (MRS) protocol to evaluate skeletal muscle metabolism in children post-HSCT. We measured demographic characteristics, aerobic exercise capacity (YMCA protocol), and skeletal muscle function in response to exercise (MRS; Siemens 3T MRI) in five children post-allogeneic HSCT and five age/body mass index-matched healthy controls (HCs). The mean age (± standard deviation) of the HSCT group and HC group were 11 ± 1.2 and 12.8 ± 2.4 years, respectively. Children post-HSCT had a lower peak aerobic exercise capacity compared to HCs (27.8 ± 3.4 vs. 40.3 ± 8.1 mL kg -1 min -1 , respectively; p = 0.015). Exercise MRS testing protocols were successfully completed by all HSCT and HC participants; however, MRS-derived skeletal muscle metabolism variables were not different between the two groups. In conclusion, the use of exercise protocols in conjunction with MRS to assess peripheral skeletal muscle metabolism was achievable in children post-HSCT. In the future, larger studies should determine if skeletal muscle function is associated with exercise capacity in children post-HSCT.

Background: Physical activity (PA) is associated with a diverse range of health benefits. International guidelines suggest that children should be participating in a minimum of 60 min of moderate to vigorous intensity PA per day to achieve these benefits. However, current guidelines are intended for healthy children, and thus may not be applicable to children with a chronic disease. Specifically, the dose of PA and disease specific exercise considerations are not included in these guidelines, leaving such children with few, if any, evidence-based informed suggestions pertaining to PA. Thus, the purpose of this narrative review was to consider current literature in the area of exercise as medicine and provide practical applications for exercise in five prevalent pediatric chronic diseases: respiratory, congenital heart, metabolic, systemic inflammatory/autoimmune, and cancer., Methods: For each disease, we present the pathophysiology of exercise intolerance, summarize the pediatric exercise intervention research, and provide PA suggestions., Results: Overall, exercise intolerance is prevalent in pediatric chronic disease. PA is important and safe for most children with a chronic disease, however exercise prescription should involve the entire health care team to create an individualized program., Conclusions: Future research, including a systematic review to create evidence-based guidelines, is needed to better understand the safety and efficacy of exercise among children with chronic disease.

Background: Children and adolescents with juvenile idiopathic arthritis (JIA) are less physically active than their healthy peers and are at high risk of missing out on the general health benefits of physical activity. Wearable activity trackers are a promising option for intervening in this population with potential advantages over traditional exercise prescriptions. The objectives of this study were to: (1) determine the feasibility of a wearable activity tracker intervention in adolescents with JIA; and (2) estimate the variability in response to a wearable activity tracker intervention on the physical activity levels of adolescents with JIA., Methods: Participants aged 12-18 years with JIA were recruited during their routine rheumatology clinic visits at a tertiary care hospital. Participants completed the 3-Day Physical Activity Recall self-reported questionnaire at baseline, 1 week and 5 week follow-up. At the 1 week follow up, participants were instructed to start wearing an activity tracker for 28 consecutive days. Participants completed a feasibility questionnaire at their end of study visit. Participant demographics, adherence rates and feasibility outcomes were summarized using descriptive statistics. The effect of wearing a tracker on moderate-to-vigorous physical activity (MVPA) and total metabolic equivalents (METs) per day were analyzed using a paired t-test., Results: Twenty-eight participants (74% female; median age 15.1, range 12.8-18.6) were included in the analysis. All of the participants were able to synchronize the activity tracker to a supported device, use the activity tracker correctly and complete the study measurements. On average, participants had activity logged on their smartphone application for 72% of the intervention period. The standard deviation of the change in mean METs/day was 12.148 and for mean MVPA blocks/day was 3.143 over the study period., Conclusion: Wrist worn activity tracking is a feasible intervention for adolescent patients with JIA. More research is needed to examine the effect of activity tracking on physical activity levels., Trial Registration: Not an applicable clinical device trial as per the criteria listed on ClinicalTrials.gov as the primary objective is feasibility.

Bone imaging is currently the best non-invasive way to assess changes to bone associated with aging or chronic disease. However, common imaging techniques such as dual energy x-ray absorptiometry are associated with limitations. Magnetic resonance imaging (MRI) is a radiation-free technique that can measure bone microarchitecture. However, published MRI bone assessment protocols use specialized MRI coils and sequences and therefore have limited transferability across institutions. We developed a protocol on a Siemens 3 Tesla MRI machine, using a commercially available coil (Siemens 15 CH knee coil), and manufacturer supplied sequences to acquire images at the tibia. We tested the reproducibility of the FSE and the GE Axial sequences and hypothesized that both would generate reproducible trabecular bone parameters. Eight healthy adults (age 25.5 ± 5.4 years) completed three measurements of each MRI sequence at the tibia. Each of the images was processed for 8 different bone parameters (such as volumetric bone volume fraction). We computed the coefficient of variation (CV) and intraclass correlation coefficients (ICC) to assess reproducibility and reliability. Both sequences resulted in trabecular parameters that were reproducible (CV <5% for most) and reliable (ICC >80% for all). Our study is one of the first to report that a commercially available MRI protocol can result in reproducible data, and is significant as MRI may be an accessible method to measure bone microarchitecture in clinical or research environments. This technique requires further testing, including validation and evaluation in other populations.

The aortic pulse wave velocity (PWV) measured via cardiac magnetic resonance (CMR) can be used to non-invasively assess changes in arterial stiffness and potential underlying vascular dysfunction. This technique could unmask early arterial dysfunction in overweight and obese youth at risk for cardiovascular disease. We sought to determine the association between vascular stiffness, percentage body fat, body mass index (BMI), and cardiac function in adolescents across the weight spectrum through both CMR and standard applanation tonometry (AT)-based PWV measurements. PWV and left-ventricular cardiac function were assessed using 3.0 T CMR in obese and overweight (OB/OW) participants (n = 12) and controls (n = 7). PWV was also estimated via carotid-femoral AT. OB/OW participants did not differ from healthy-weight controls regarding cardiometabolic risk factors or physical activity levels, but there was a trend towards higher levels of triglycerides in obese/overweight participants (P = 0.07). Mean PWV was higher in obese participants when corrected for age and sex (P = 0.01), and was positively associated with BMI (β = 0.51, P = 0.02). PWV estimated through AT was not significantly different between groups. Cardiac function measured by left-ventricular ejection fraction z-score was inversely associated with mean PWV (β = -0.57, P = 0.026). Increasing arterial stiffness and decreasing cardiac function were evident among our overweight and obese cohort. PWV estimated by CMR could detect early increases in arterial stiffness vs. traditional AT measurements of PWV., (© 2017 World Obesity Federation.)

Background: Malignant hyperthermia (MH), a pharmacogenetic disorder of skeletal muscle, presents with a potentially lethal hypermetabolic reaction to certain anesthetics. However, some MH-susceptible patients experience muscle weakness, fatigue, and exercise intolerance in the absence of anesthetic triggers. The objective of this exploratory study was to elucidate the pathophysiology of exercise intolerance in patients tested positive for MH with the caffeine-halothane contracture test. To this end, we used phosphorus magnetic resonance spectroscopy, blood oxygen level-dependent functional magnetic resonance imaging (MRI), and traditional exercise testing to compare skeletal muscle metabolism in MH-positive patients and healthy controls., Methods: Skeletal muscle metabolism was assessed using phosphorus magnetic resonance spectroscopy and blood oxygen level-dependent functional MRI in 29 MH-positive patients and 20 healthy controls. Traditional measures of physical capacity were employed to measure aerobic capacity, anaerobic capacity, and muscle strength., Results: During 30- and 60-second exercise, MH-positive patients had significantly lower ATP production via the oxidative pathway compared to healthy controls. MH-positive patients also had a longer recovery time with blood oxygen level-dependent functional MRI compared to healthy controls. Exercise testing revealed lower aerobic and anaerobic capacity in MH-positive patients compared to healthy controls., Conclusions: Results of this exploratory study suggest that MH-positive patients have impaired aerobic metabolism compared to healthy individuals. This could explain the exercise intolerance exhibited in MH-susceptible patient population.

Background: Obesity is associated with cardiometabolic disturbances, which may have significant implications for musculoskeletal health and exercise tolerance., Objective: We sought to determine the association between muscle structure, function, and metabolism in adolescents across the weight spectrum., Methods: This cross-sectional case-control study included overweight and obese participants (n = 24) 8-18 years of age with a body mass index (BMI) ≥ 85th percentile for age and gender, and non-obese participants (n = 24) with a BMI < 85 th percentile. Body composition, physical activity, peak aerobic capacity, cardiometabolic blood markers and insulin resistance (measured by the homeostatic model assessment of insulin resistance, HOMA-IR), skeletal muscle mitochondrial oxidative capacity (via 31 Phosphorous-Magnetic Resonance Spectroscopy, 31 P-MRS, to assess phosphocreatine (PCr) recovery after exercise), and extramyocellular and intramyocellular lipid (IMCL) levels (via 1 Hydrogen-MRS) were assessed. Stepwise regression was performed to examine the factors associated with oxidative capacity., Results: bese and overweight patients had similar age, height, and physical activity to non-obese controls, but obese and overweight participants exhibited higher insulin resistance. Obese and overweight participants had longer PCr recovery than non-obese controls following 5x30s of moderate-intensity exercise (51.2 ± 20.1 s vs. 23.9 ± 7.5 s, p = 0.004). In univariate correlation analysis, impaired PCr recovery was associated with a higher BMI z-score (r s  = 0.51, p < 0.001), circulating triglycerides (r s  = 0.41, p = 0.005), and HOMA-IR (r s  = 0.46, p = 0.001). In stepwise multivariate regression analysis, impaired PCr recovery was associated with a higher BMI z-score (β = 0.47, p = 0.002), but not insulin resistance (β = 0.07, p = 0.07) or circulating triglycerides (β = 0.16 p = 0.33)., Conclusion: A slower phosphocreatine recovery following aerobic exercise is strongly associated with increasing adiposity. A slower metabolic recovery following aerobic exercise stress suggests that endurance exercise training in obese adolescents may be an optimal strategy to target exercise intolerance in this cohort., (© 2016 World Obesity Federation.)

Purpose: Sprint interval training (SIT) stimulates rapid metabolic adaptations within skeletal muscle but the nature of neuromuscular adaptions is unknown. Omega-3 polyunsaturated fatty acids (N-3 PUFA) are suggested to enhance neuromuscular adaptations to exercise., Methods: We measured the neuromuscular adaptations to SIT (Study-1) and conducted a placebo-controlled randomized double blinded study to determine the effect of N-3 PUFA supplementation on neuromuscular adaptations to SIT (Study-2). In Study-1, seven active men (24.4 ± 2.6 years, VO 2 peak 43.8 ± 8.7 ml kg min -1 ) completed 2-weeks of SIT with pre- and post-training 10 km cycling time trials (TT). In Study-2, 30 active men (24.5 ± 4.2 years, VO 2 peak 41.0 ± 5.1 ml kg min -1 ) were randomly assigned to receive N-3 PUFA (2330 mg day -1 ) (n = 14) or olive oil (n = 16) during 2-weeks of SIT with pre- and post-training TTs. Four week post-training, a SIT session and TT were also performed. Change in neuromuscular function was assessed from resting twitches, quadriceps maximal voluntary contraction (MVC) force, and potentiated twitch force (Q tw )., Results: Study-1 showed that SIT did not elicit significant neuromuscular adaptations. Study-2 showed that N-3 PUFA supplementation had no significant effect on neuromuscular adaptations. Training caused lower MVC force [mean ± SD; N-3 PUFA -9 ± 11%, placebo -9 ± 13% (p < 0.05 time)] and Q tw peripheral fatigue [N-3 PUFA -10 ± 19%, placebo -14 ± 13% (p < 0.05 time)]. TT time was lower after training in all groups [Study-1 -10%, Study-2 N-3 PUFA -8%, placebo -12% (p < 0.05 time)]., Conclusion: Two weeks of SIT improved TT performance in the absence of measurable neuromuscular adaptations. N-3 PUFA supplementation had no significant effect on SIT training adaptations.

Mild traumatic brain injury (mTBI) is common in youth, especially in those who participate in sport. Recent investigations from our group have shown that asymptomatic children and adolescents with mTBI continue to exhibit alterations in neural activity and cognitive performance compared with those without a history of mTBI. This is an intriguing finding, given that current return-to-learn and return-to-play protocols rely predominately on subjective symptom reports, which may not be sensitive enough to detect subtle injury-related changes. As a result, youth may be at greater risk for re-injury and long-term consequences if they are cleared for activity while their brains continue to be compromised. It is currently unknown whether mTBI also affects brain microstructure in the developing brain, particularly cortical thickness, and whether such changes are also related to cognitive performance. The present study examined cortical thickness in 13 asymptomatic youth (10-14 years old) who had sustained an mTBI 3-8 months prior to testing compared with 14 age-matched typically developing controls. Cortical thickness was also examined in relation to working memory performance during single and dual task paradigms. The results show that youth who had sustained an mTBI had thinner cortices in the left dorsolateral prefrontal region and right anterior and posterior inferior parietal lobes. Additionally, cortical thinning was associated with slower reaction time during the dual-task condition in the injured youth only. The results also point to a possible relationship between functional and structural alterations as a result of mTBI in youth, and lend evidence for neural changes beyond symptom resolution.

Non-communicable disease is a leading threat to global health. Physical inactivity is a large contributor to this problem; in fact, the WHO ranks it as the fourth leading risk factor for overall morbidity and mortality worldwide. In Canada, at least 4 of 5 adults do not meet the Canadian Physical Activity Guidelines of 150 min of moderate-to-vigorous physical activity per week. Physicians play an important role in the dissemination of physical activity (PA) recommendations to a broad segment of the population, as over 80% of Canadians visit their doctors every year and prefer to get health information directly from them. Unfortunately, most physicians do not regularly assess or prescribe PA as part of routine care, and even when discussed, few provide specific recommendations. PA prescription has the potential to be an important therapeutic agent for all ages in primary, secondary and tertiary prevention of chronic disease. Sport and exercise medicine (SEM) physicians are particularly well suited for this role and should collaborate with their primary care colleagues for optimal patient care. The purpose of this Canadian Academy and Sport and Exercise Medicine position statement is to provide an evidence-based, best practices summary to better equip SEM and primary care physicians to prescribe PA and exercise, specifically for the prevention and management of non-communicable disease. This will be achieved by addressing common questions and perceived barriers in the field.Author note This position statement has been endorsed by the following nine sport medicine societies: Australasian College of Sports and Exercise Physicians (ACSEP), American Medical Society for Sports Medicine (AMSSM), British Association of Sports and Exercise Medicine (BASEM), European College of Sport & Exercise Physicians (ECOSEP), Norsk forening for idrettsmedisin og fysisk aktivite (NIMF), South African Sports Medicine Association (SASMA), Schweizerische Gesellschaft für Sportmedizin/Swiss Society of Sports Medicine (SGSM/SSSM), Sport Doctors Australia (SDrA), Swedish Society of Exercise and Sports Medicine (SFAIM), and CASEM., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Exercise- and hypoxia-induced hyperventilation decreases the partial pressure of end-tidal carbon dioxide (PETCO2), which in turn exerts many physiological effects. Several breathing circuits that control PETCO2 have been previously described, but their designs are not satisfactory for exercise studies where changes in inspired oxygen (FIO2) may be desired. This study is the first report of a breathing system that can maintain PETCO2 constant within a single session of graded submaximal exercise and graded hypoxia. Thirteen fit and healthy subjects completed two bouts of exercise consisting of three 3min stages on a cycle ergometer with increasing exercise intensity in normoxia (Part A; 142±14, 167±14, 192±14W) or with decreasing FIO2 at a constant exercise intensity (Part B; 21, 18, and 14%). One bout was a control (CON) where PETCO2 was not manipulated, while during the other bout the investigator clamped PETCO2 within 2mmHg (CO2Clamp) using sequential gas delivery (SGD). During the final 30s of each exercise stage during CO2Clamp, PETCO2 was successfully maintained in Part A (43±4, 44±4, 44±3mmHg; P=0.44) and Part B (45±3, 46±3, 45±3mmHg; P=0.68) despite the increases in ventilation due to exercise. These findings demonstrate that this SGD circuit can be used to maintain isocapania in exercising humans during progressively increasing exercise intensities and changing FIO2., (Copyright © 2016 Elsevier B.V. All rights reserved.)

We sought to determine whether a 9-day remote ischemic preconditioning (IPC) causes improvements in exercise performance, energetics, and blood pressure. Ten participants (mean age 24 ± 4 years) had no changes in aerobic capacity (preintervention: 38 ± 10 mL/(kg·min)(-1) vs. postintervention: 38 ± 10 mL/(kg·min)(-1)), blood pressure (preintervention: 112 ± 7/66 ± 6 mm Hg vs. postintervention: 112 ± 10/62 ± 5 mm Hg), cardiac phosphocreatinine-to-adenosine-triphosphate ratio (preintervention: 2.1 ± 0.5 vs. postintervention: 2.3 ± 0.4), and postexercise skeletal muscle phosphocreatine recovery (preintervention: 34 ± 11 s vs. postintervention: 31 ± 11 s). Short-term remote IPC may be ineffective in improving these outcomes.

Fetal movements, which include body and breathing movement, are important indicators of fetal well-being and nervous system development. These have been shown to be affected by intrauterine conditions. While maternal physical activity does induce a change in intrauterine conditions and physiology, its impact on fetal movements is still unclear. This paper will provide a brief review of the literature and outline the current knowledge with regards to the effects of maternal exercise on fetal body and breathing movements., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Biomarkers of inflammation, muscle damage, and oxidative stress after high-intensity exercise have been described previously; however, further understanding of their role in the postexercise recovery period is necessary. Because these markers have been implicated in cell signaling, they may be specifically related to the training adaptations induced by high-intensity exercise. Thus, a clear model showing their responses to exercise may be useful in characterizing the relative recovery status of an athlete. The purpose of this study was twofold: (a) to investigate the time course of markers of muscle damage and inflammation in the blood from 3 to 72 hours after combined training exercises and (b) to investigate indicators of oxidative stress and damage associated with increased reactive oxygen species production during high-intensity exercise in elite athletes. Nineteen male athletes performed a combination of high-intensity aerobic and anaerobic training exercises. Samples were acquired immediately before and at 3, 6, 12, 24, 48, and 72 hours after exercise. The appearance and clearance of creatine kinase and lactate dehydrogenase in the blood occurred faster than previous studies have reported. The neutrophil/lymphocyte ratio summarizes the mobilization of 2 leukocyte subpopulations in a single marker and may be used to predict the end of the postexercise recovery period. Further analysis of the immune response using serum cytokines indicated that high-intensity exercise performed by highly trained athletes only generated inflammation that was localized to the skeletal muscle. Biomarkers are not a replacement for performance tests, but when used in conjunction, they may offer a better indication of metabolic recovery status. Therefore, the use of biomarkers can improve a coach's ability to assess the recovery period after an exercise session and to establish the intensity of subsequent training sessions.

Human experimentation investigating the contribution of limb movement frequency in determining the fast exercise drive to breathe has produced controversial findings. To evaluate the role of limb movement frequency in determining the fast exercise drive to breathe, endurance runners and recreationally-active controls performed two sinusoidal exercise protocols on a cycle ergometer. One protocol was performed at constant workload with sinusoidal pedaling cadence, and a second with sinusoidal workload at constant cadence. Metabolic rate (VO2) increases and means were matched between these two experiments. The ventilatory response was significantly faster when limb movement speed was varied, compared to when pedal loading was varied (18.49 ± 15.6s vs. 50.5 ± 14.5s, p<0.05). Ventilation response amplitudes were significantly higher during pedal cadence variation versus pedal loading variation (3.99 ± 0.25 vs. 2.58 ± 0.17 L/min, p<0.05). Similar findings were obtained for endurance athletes, with significantly attenuated ventilation responses to exercise versus control subjects. We conclude that fast changes in limb movement frequency are a potent stimulus for ventilation at submaximal workloads, and that this response is susceptible to attenuation through training., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Omega-3 polyunsaturated fatty acids (N-3) are essential nutrients for human health and integral components of neural tissues. There is evidence that N-3 supplementation may benefit exercise performance, however, no study has investigated the ergogenic potential of N-3 supplementation. Our objective was to determine the effect of short-term N-3 supplementation on neuromuscular-function and physical-performance in well-trained athletes., Methods: Male athletes (n = 30), 25 years (SD 4.6), training 17 h(.)wk(-1) (SD 5) completed this randomized, placebo-controlled, parallel-design study. At baseline a blood sample was collected, maximal voluntary isometric contractions (MVC) with electromyography (EMG) recordings were measured, and participants underwent various performance tests including a Wingate test and 250 kJ time trial (TT) followed by repeated MVC and EMG measurement. Participants were then randomly assigned to receive N-3 (5 ml seal oil, 375 mg EPA, 230 mg DPA, 510 mg DHA) or placebo (5 ml olive oil) for 21-days after which baseline testing was repeated. The magnitude-based inference approach was used to estimate the probability that N-3 had a beneficial effect on neuromuscular-function and performance of at least ±1%. Data are shown as mean ± 90% confidence-interval., Results: Plasma EPA was higher on N-3 than placebo (p = 0.004) but the increases in DPA and DHA were not significant (p = 0.087, p = 0.058). N-3 supplementation had an unclear effect on MVC force (4.1 ± 6.6%) but increased vastus lateralis EMG by 20 ± 18% vs placebo (very likely beneficial). N-3 supplementation reduced Wingate percent power drop by 4.76 ± 3.4 % vs placebo (very likely beneficial), but the difference in TT performance was unclear (-1.9 ± 4.8%)., Conclusion: Our data indicates N-3 PUFA supplementation improved peripheral neuromuscular function and aspects of fatigue with an unclear effect on central neuromuscular function. Clinical trial registration NCT0201433.

Object: There have been no studies to investigate the effects of cycling exercise protocols, as well as repeated bouts of exercise, on the blood oxygen level-dependent (BOLD) response in the quadriceps muscles. This study characterized BOLD signal recovery following non-ischemic bouts of exercise in the quadriceps muscles of healthy adults in order to provide a basis for application of a protocol for clinical populations., Materials and Methods: Healthy male subjects (23.7 ± 2.0 years of age, n = 10) completed three cycles of one-minute exercise (65 % of maximum workload), with two minutes of rest between each bout, on an MRI-compatible ergometer. The BOLD responses during recovery were fitted to a sigmoid model, and response kinetics (post-exercise intensity [S0]), response time (α), change in baseline BOLD signal (κ), and inflection point (β)] were measured., Results: The sigmoid function fit well to the post-exercise BOLD data (r (2) = 0.95 ± 0.04). The mean response time was 10.5 ± 3.8 seconds, change in baseline BOLD intensity was 0.15 ± 0.068, and time to half-peak was 20.2 ± 8.6 seconds., Conclusion: The proposed sigmoid model is a robust method for quantifying quadriceps BOLD response post-exercise without induced ischemia. Extension of this model to evaluate microvascular responses in patients with chronic disease could improve our understanding of exercise intolerance.

Objective: To study the effects of L-arginine (L-Arg) on total body aerobic capacity and muscle metabolism as assessed by (31)Phosphorus Magnetic Resonance Spectroscopy ((31)P-MRS) in patients with MELAS (Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episodes) syndrome., Methods: We performed a case control study in 3 MELAS siblings (m.3243A>G tRNA(leu(UUR)) in MTTL1 gene) with different % blood mutant mtDNA to evaluate total body maximal aerobic capacity (VO(2peak)) using graded cycle ergometry and muscle metabolism using 31P-MRS. We then ran a clinical trial pilot study in MELAS sibs to assess response of these parameters to single dose and a 6-week steady-state trial of oral L-Arginine., Results: At baseline (no L-Arg), MELAS had lower serum Arg (p = 0.001). On 3(1)P-MRS muscle at rest, MELAS subjects had increased phosphocreatine (PCr) (p = 0.05), decreased ATP (p = 0.018), and decreased intracellular Mg(2+) (p = 0.0002) when compared to matched controls. With L-arginine therapy, the following trends were noted in MELAS siblings on cycle ergometry: (1) increase in mean % maximum work at anaerobic threshold (AT) (2) increase in % maximum heart rate at AT (3) small increase in VO(2peak). On (31)P-MRS the following mean trends were noted: (1) A blunted decrease in pH after exercise (less acidosis) (2) increase in Pi/PCr ratio (ADP) suggesting increased work capacity (3) a faster half time of PCr recovery (marker of mitochondrial activity) following 5 minutes of moderate intensity exercise (4) increase in torque., Significance: These results suggest an improvement in aerobic capacity and muscle metabolism in MELAS subjects in response to supplementation with L-Arg. Intramyocellular hypomagnesemia is a novel finding that warrants further study., Classification of Evidence: Class III evidence that L-arginine improves aerobic capacity and muscle metabolism in MELAS subjects., Trial Registration: ClinicalTrials.gov NCT01603446.

Alpine skiing is a high-intensity intermittent sport that results in lactate accumulation and muscle acidosis, which has been shown to contribute to peripheral neuromuscular fatigue. Active recovery influences the removal of lactate from the muscle and blood by maintaining blood flow to fatigued muscles and enhancing aerobic utilization of lactate by nonfatigued tissues. The purpose of this study was to investigate the effect of on-hill active recovery on blood lactate concentration in alpine skiers. Fourteen highly trained alpine skiers (7 women, 7 men) completed 8 training runs in a 45-gate slalom or a 25-gate giant slalom corridor at 2,600 m above sea level. Skiers were randomized to active (ACT) or static recovery (CON) performed at the top of each run. Blood lactate concentration and perceived fatigue were recorded at the top and bottom of each run. Performance was measured by time to complete each training run and rate of incomplete runs. A significant time (p < 0.01) and interaction (p = 0.001) effect was observed for blood lactate concentration measured at the top, with ACT being associated with significantly lower values. A significant time effect (p < 0.001) was observed for blood lactate concentration measured at the bottom. Training run completion time was longer (p ≤ 0.05), and higher rate of incomplete runs were observed in the CON group, despite no between-group differences in rating of perceived fatigue. On-hill active recovery performed between runs promotes blood lactate clearance in alpine skiers and is associated with delayed fatigue as indicated by faster training runs and fewer incomplete runs.

Background: Exercise intolerance is prevalent in individuals with Turner Syndrome (TS). We recently demonstrated that girls with TS have normal aerobic but altered skeletal muscle anaerobic metabolism compared to healthy controls (HC). The purpose of this study was to compare peripheral skeletal muscle microvascular function in girls with TS to HC after exercise. We hypothesized that girls with TS would have similar muscle blood-oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) signal responses during recovery from exercise compared to HC., Methods: Thirteen TS participants and 8 HC completed testing. BOLD MRI was used to measure skeletal muscle microvascular response during 60 second recovery, following 60 s of exercise at 65% of maximal workload. Exercise and recovery were repeated four times, and the BOLD signal time course was fit to a four-parameter sigmoid function., Results: Participants were 13.7 ± 3.1 years old and weighed 47.9 ± 14.6 kg. The mean change in BOLD signal intensity following exercise at the end of recovery, the mean response time of the function/the washout of deoxyhemoglobin, and the mean half-time of recovery were similar between the TS and HC groups., Conclusions: Our results demonstrate that compared to HC, peripheral skeletal muscle microvascular function following exercise in girls with TS is not impaired., General Significance: This study supports the idea that the aerobic energy pathway is not impaired in children with TS in response to submaximal exercise. Other mechanisms are likely responsible for exercise intolerance in TS; this needs to be further investigated.

Purpose: The purpose of this study was to investigate the effects of different cold-water immersion (CWI) protocols on the inflammatory response to and functional recovery from high-intensity exercise., Methods: Eight healthy recreationally active males completed five trials of a high-intensity intermittent sprint protocol followed by a randomly assigned recovery condition: 1 of 4 CWI protocols (CWI-10 min × 20 °C, CWI-30 min × 20 °C, CWI-10 min × 10 °C, or CWI-30 min × 10 °C) versus passive rest. Circulating mediators of the inflammatory response were measured from EDTA plasma taken pre-exercise (baseline), immediately post-exercise, and at 2, 24, and 48 h post-exercise. Ratings of perceived soreness and impairment were noted on a 10-pt Likert scale, and squat jump and drop jump were performed at these time points., Results: IL-6, IL-8, and MPO increased significantly from baseline immediately post-exercise in all conditions. IL-6 remained elevated from baseline at 2 h in the CWI-30 min × 20 °C, CWI-10 min × 10 °C, and CWI-30 min × 10 °C conditions, while further increases were observed for IL-8 and MPO in the CWI-30 min × 20 °C and CWI-30 min × 10 °C conditions. Squat jump and drop jump height were significantly lower in all conditions immediately post-exercise and at 2 h. Drop jump remained below baseline at 24 and 48 h in the CON and CWI-10 min × 20 °C conditions only, while squat jump height returned to baseline in all conditions., Conclusions: Cold-water immersion appears to facilitate restoration of muscle performance in a stretch-shortening cycle, but not concentric power. These changes do not appear to be related to inflammatory modulation. CWI protocols of excessive duration may actually exacerbate the concentration of cytokines in circulation post-exercise; however, the origin of the circulating cytokines is not necessarily skeletal muscle.

Rationale: Although peak aerobic capacity (VO(2peak)) has been linked to outcome in patients with cystic fibrosis (CF), measuring is time consuming, and requires expensive equipment and expertise that is not readily available in all centers. Other fitness parameters such as peak anaerobic power, measures of power and strength may be simpler to deliver in the clinic. The relationship between these measures and established outcomes such as forced expiratory volume in one second (FEV(1)) and peak aerobic power (VO(2peak)) in CF remains unclear. Therefore we evaluated (a) aerobic fitness, (b) anaerobic fitness, and (c) upper and lower body muscle strength to determine their relationship to FEV(1) and VO(2peak) in children with CF., Methods: Eighty-two patients (7-18 years) with CF (40 female) from the CF clinic at The Hospital for Sick Children in Toronto performed a maximal incremental cycling test to exhaustion. Anaerobic power (W) for 10 and 30 sec cycling trials as well as vertical jump (VJ) and hand grip strength (HG) were compared to FEV(1) and VO(2peak)., Results: Absolute VO(2peak) (R(2)  = 0.16, P < 0.001), anaerobic power (R(2)  = 0.21, P < 0.001), and hand grip strength (R(2)  = 0.10, P = 0.003) were significantly correlated to lung function whereas measures of explosive lower body strength (VJ) were not. Anaerobic power (R(2)  = 0.16, P = 0.001) and hand grip strength (R(2)  = 0.08, P = 0.01) were related to VO(2peak). Vertical jump was correlated with VO(2peak) (R(2)  = 0.29, P < 0.001) but not FEV(1)., Conclusions: Simple fitness tests such as hand grip strength and anaerobic cycle tests may be useful indicators of lung health and fitness., (© 2013 Wiley Periodicals, Inc.)

Hematopoietic stem-cell transplant (SCT) is increasingly used to treat children with cancer, and survival following SCT is improving. One predominant consequence of childhood cancer therapy is increased physical morbidity, which is worse in pediatric SCT recipients compared with children treated with chemotherapy or radiation alone. There are many factors that contribute to exercise intolerance and reduced physical function during the pretransplant, peritransplant, and posttransplant phases. These include side effects from chemotherapy or radiation, excessive immobility due to bed rest, infections, the negative effects of immunosuppressants, and graft vs host disease, all of which can impair cardiorespiratory fitness, muscle strength, and muscle function. Few studies have investigated the effects of exercise in childhood SCT recipients. In a small number of published studies, exercise interventions have been demonstrated to improve cardiorespiratory fitness, preserve or increase muscle mass, and improve muscle strength in children following SCT. The use of exercise as medicine may be a noninvasive and nonpharmaceutical treatment to target physical complications post-SCT. Researchers and health-care professionals should work together to develop exercise prescription guidelines for this unique and important population.

Background: A double-blinded, placebo-controlled, cross-over design was used to investigate whether two different sodium citrate dihydrate (Na-CIT) supplementation protocols improve 200 m swimming performance in adolescent swimmers., Methods: Ten, male swimmers (14.9 ± 0.4 years of age; 63.5 ± 4 kg) performed four 200 m time trials with the following treatments: acute (ACU) supplementation (0.5 g kg(-1) administered 120 min pre-trial), acute placebo (PLC-A), chronic (CHR) supplementation (0.1 g∙kg(-1) for three days and 0.3 g kg(-1) on the forth day 120 min pre-trial), and chronic placebo (PLC-C). The order of the trials was randomized, with at least a six-day wash-out period between trials. Blood samples were collected by finger prick pre-ingestion, 100 min post-ingestion, and 3 min post-trial. Performance time, rate of perceived exertion, pH, base excess, bicarbonate and lactate concentration were measured., Results: Post-ingestion bicarbonate and base excess were higher (P < 0.05) in both the ACU and CHR trials compared to placebo showing adequate pre-exercise alkalosis. However, performance time, rate of perceived exertion as well as post-trial pH and lactate concentration were not significantly different between trials. Further analysis revealed that five swimmers, identified as responders, improved their performance time by 1.03% (P < 0.05) and attained higher post-trial lactate concentrations in the ACU versus PLC-A trial (P < 0.05). They also had significantly higher post-trial lactate concentrations compared to the non-responders in the ACU and CHR trials., Conclusions: Acute supplementation of Na-CIT prior to 200 m swimming performance led to a modest time improvement and higher blood lactate concentrations in only half of the swimmers while the chronic Na-CIT supplementation did not provide any ergogenic effect in this group of adolescent swimmers., Trial Registration: Clinicaltrials.gov NCT01835912.

Exercise is beneficial for patients with cystic fibrosis (CF) but long-term effects of physical activity on lung function evolution are unknown. We evaluated the longitudinal relationship between changes in habitual physical activity (HPA) and rate of decline in lung function in patients with CF. We tracked HPA using the Habitual Activity Estimation Scale, forced expiratory volume in 1 s (FEV₁) and Stage I exercise tests in 212 patients with CF over a 9-year period. Adjusting for sex, baseline age and FEV₁, mucoid Pseudomonas aeruginosa and CF-related diabetes, mean ± sd FEV₁ % predicted decreased by 1.63 ± 0.08% per year (p<0.0001) while mean ± sd HPA increased by 0.28 ± 0.03 h·day(-1) per year (p<0.0001) over the study period. A greater increase in HPA was associated with a slower rate of decline in FEV₁ (r=0.19, p<0.0069). Dividing subjects into "high" and "low" activity (above or below the mean rate of change of activity, respectively), a steeper rate of FEV₁ decline was observed for low (-1.90% per year) compared to high (-1.39% per year) (p=0.002). Increases in HPA are feasible despite progression of lung disease and are associated with a slower rate of decline in FEV₁, highlighting the benefit of regular physical activity, and its positive impact on lung function in patients with CF.

(31)Phosphorus Magnetic Resonance Spectroscopy ((31)P MRS) is a well-validated, noninvasive magnetic resonance imaging technique that has been used to determine cardiac and skeletal muscle energy metabolism in vivo. Few studies have documented cardiac energy metabolism in adolescents and young adult cohorts. This cross-sectional study sought to explore the association among cardiac energy metabolism, skeletal muscle energy metabolism, moderate-to-vigorous physical activity (MVPA), and age in adolescents and young adults. Ten healthy, active participants (40% male) with a mean ± SD age of 18.6 ± 4.9 years, body mass index of 21.1 ± 2.4 kg·m(-2), and median MVPA level of 83 min per weekday (lower quartile: 45 min per weekday; upper quartile: 114 min per weekday) completed the following study assessments: a (31)P MRS scan to determine cardiac and skeletal muscle energy metabolism, cardiopulmonary exercise testing to determine aerobic power, and accelerometry to determine MVPA over 7 days. Resting cardiac energy metabolism, as measured by the ratio of phosphocreatine to adenosine triphosphate (PCr/ATPβ, mean ± SD: 2.76 ± 0.65), was positively associated with skeletal muscle aerobic oxidative function (Estimate (SE): -0.1(0.01), p < 0.001), as measured by PCr recovery half-time following 60 s of exercise (34 ± 9 s). This association, which was adjusted for peak aerobic power, MVPA, age, and sex, suggests the development of an association between cardiac and skeletal muscle health at any early age. Larger studies are needed to establish normative data for both physically active and sedentary males and females that may be used for comparison in future studies involving clinical cohorts.

Purpose: To critically review the methodological quality and synthesize information from systematic reviews and high quality studies on the effects of beta alanine (BA) on exercise and athletic performance., Methods: A search strategy was developed in accordance with the standards for the reporting of scientific literature via systematic reviews. Five databases were thoroughly searched from inception to November 2012. Inclusion criteria were English language, human studies, used BA to increase exercise or athletic performance, systematic reviews or randomized controlled trials and were published in a peer-reviewed journal. Included studies were systematically graded for their methodological quality by rotating pairs of reviewers and the results were qualitatively synthesized., Results: One systematic review and 19 randomized trials were included in this review. There is one systematic review with several methodological weaknesses that limit the confidence in its results. There are moderate to high quality studies that appear to support that BA may increase power output and working capacity, decrease the feeling of fatigue and exhaustion, and have of positive effect on body composition and carnosine content. The reporting of side effects from BA supplementation in the athletic population was generally under-reported., Conclusions: There appears to be some evidence from this review that supplementation with BA may increase athletic performance. However, there is insufficient evidence examining the safety of BA supplementation and its side effects. It is therefore recommended to err on the side of caution in using BA as an ergogenic aid until there is sufficient evidence confirming its safety.

Objective: The objective of the study was to investigate the cerebrovascular hemodynamic response of cervical spine positions including rotation and cervical spine manipulation in vivo using magnetic resonance imaging technology on the vertebral artery (VA)., Methods: This pilot study was conducted as a blinded examiner cohort with 4 randomized clinical tasks. Ten healthy male participants aged 24 to 30 years (mean, 26.8 years) volunteered to participate in the study. None of the participants had a history of disabling neck, arm, or headache pain within the last 6 months. They did not have any current or history of neurologic symptoms. In a neutral head position, physiologic measures of VA blood flow and velocity at the C1-2 spinal level were obtained using phase-contrast magnetic resonance imaging after 3 different head positions and a chiropractic upper cervical spinal manipulation. A total of 30 flow-encoded phase-contrast images were collected over the cardiac cycle, in each of the 4 conditions, and were used to provide a blood flow profile for one complete cardiac cycle. Differences between flow (in milliliters per second) and velocity (in centimeters per second) variables were evaluated using repeated-measures analysis of variance., Results: The side-to-side difference between ipsilateral and contralateral VA velocities was not significant for either velocities (P = .14) or flows (P = .19) throughout the conditions. There were no other interactions or trends toward a difference for any of the other blood flow or velocity variables., Conclusions: There were no significant changes in blood flow or velocity in the vertebral arteries of healthy young male adults after various head positions and cervical spine manipulations., (© 2014. Published by National University of Health Sciences All rights reserved.)

High-intensity exercise is associated with mechanical and/or metabolic stresses that lead to reduced performance capacity of skeletal muscle, soreness and inflammation. Cold-water immersion and other forms of cryotherapy are commonly used following a high-intensity bout of exercise to speed recovery. Cryotherapy in its various forms has been used in this capacity for a number of years; however, the mechanisms underlying its recovery effects post-exercise remain elusive. The fundamental change induced by cold therapy is a reduction in tissue temperature, which subsequently exerts local effects on blood flow, cell swelling and metabolism and neural conductance velocity. Systemically, cold therapy causes core temperature reduction and cardiovascular and endocrine changes. A major hindrance to defining guidelines for best practice for the use of the various forms of cryotherapy is an incongruity between mechanistic studies investigating these physiological changes induced by cold and applied studies investigating the functional effects of cold for recovery from high-intensity exercise. When possible, studies investigating the functional recovery effects of cold therapy for recovery from exercise should concomitantly measure intramuscular temperature and relevant temperature-dependent physiological changes induced by this type of recovery strategy. This review will discuss the acute physiological changes induced by various cryotherapy modalities that may affect recovery in the hours to days (<5 days) that follow high-intensity exercise.

Context: Turner syndrome (TS) is a chromosomal disorder occurring in approximately 1 in 2500 live births. Individuals with TS report lower levels of physical activity than healthy control (HC) subjects. Cardiorespiratory limitations may contribute to the observed reduction in physical activity., Objective: The objective of this study was to compare muscle metabolism of patients with TS vs HC subjects before and after exercise using exercise testing, magnetic resonance imaging, and magnetic resonance spectroscopy techniques., Design: We hypothesized that girls and adolescents with TS would have muscle metabolic abnormalities not present in the HC population., Setting: The research was conducted at the Hospital for Sick Children in Toronto, Ontario, Canada., Participants: Fifteen participants with TS were age-, activity-, and body mass index Z-score-matched with 16 HC subjects., Main Outcome Measures: (31)P magnetic resonance spectroscopy was used to characterize muscle metabolism at rest and after 30 seconds of high-intensity exercise, 60 seconds of moderate-intensity exercise, and 5 minutes of low-intensity exercise., Results: While achieving the same workloads, participants with TS exhibited a greater difference between rest and end-exercise pH compared with HC subjects after 30 seconds (TS, 0.29 ± 0.04; HC, 0.21 ± 0.08; P = .03) and 90 seconds (TS, 0.47 ± 0.22; HC, 0.32 ± 0.13; P = .02) of exercise. During the 5-minute exercise test, similar workloads were achieved between groups; however, ATP production was greater in participants with TS vs the HC subjects via all 3 bioenergetic pathways (total ATP: TS, 0.90 ± 0.34; HC, 0.60 ± 0.25; P = .01)., Conclusions: The results of this study suggest that patients with TS exhibit greater anaerobic stress during exercise than HC subjects, which may lead to symptoms of increased muscle fatigue with short bursts of activity. Recovery metabolism after exercise appears to be similar between participants with TS and HC subjects, which is suggestive of normal mitochondrial metabolism and oxygen transport.