Potential relevance of a motor skill "proficiency barrier" on health-related fitness in youth.

This study investigated the potential impact of a motor skill proficiency barrier on measures of cardiorespiratory (CRF) and musculoskeletal (MSF) fitness in youth. A sample of 241 youth (114 girls) aged 10 - 18 years, completed the Motor Competence Assessment battery with composite scores indexed according to age- and gender-adjusted percentile scores. Motor competence (MC) levels were categorized as low (≤ 25%tile - proficiency barrier), moderate (≥ 26%tile to < 75%tile), and high (≥ 75%tile). CRF levels (Health Risk, Needs Improvement, and Healthy) were assessed using the Fitnessgram® 20 m PACER test. Low (≤ 20%tile), moderate (≥ 21%tile to ≤ 80%tile), and high (≥ 80%tile) MSF levels were assessed using grip strength normative data. Two 3 × 3 chi-square tests were conducted to determine the probability of MC level predicting CRF and MSF levels. Results demonstrated statistically significant models for performance on both the PACER (χ2[4, N = 241] = 22.65, p < .001) and grip strength (χ2[4, N = 241] = 23.95, p < .001). Strong evidence of a proficiency barrier impacting CRF was noted, as no low skilled youth met the "Healthy" fitness zone standards for PACER performance. Evidence supporting a barrier with grip strength was not as strong, as 20.8% of youth exhibiting low MC displayed high grip strength. However, all individuals with high levels of MC demonstrated at least moderate grip strength. Results emphasize the importance of developing MC during childhood as it may provide a protective effect against unhealthy CRF and MSF across youth.HighlightsThese data support the notion of Seefeldt's (1980) proficiency barrier as it relates to CRF, as no youth demonstrating low MC met the healthy fitness zone criteria for PACER performance. The development of MC may both directly and indirectly provide a protective effect against unhealthy CRF levels across childhood and adolescence.Evidence supporting a proficiency barrier with MSF as measured by grip strength was not as strong; however, all individuals with high levels of MC demonstrated at least moderate grip strength. Thus, the development of MC may be a protective factor to mitigate low levels of MSF via enhanced neuromuscular function.Promoting the development of MC in a variety of developmentally appropriate activities and settings (e.g. MC skills practice, structured and unstructured play, and performance contexts) is important to promote positive trajectories of CRF and MSF across childhood and adolescence.

Comparison of Physical Activity Between Children With and Without Autism Spectrum Disorder: A Systematic Review and Meta-Analysis.

Lower levels of physical activity (PA) are often observed among children with autism spectrum disorder (ASD) compared to children without ASD; however, some studies have demonstrated few to no PA differences between the two groups. The purpose of this systematic review with meta-analysis was to compare the differences in PA between children (2-18 years) with and without ASD. An exhaustive search of five online databases was completed, and 31 studies met the inclusion criteria. A pooled random-effects Hedges's g model was used to determine differences in PA between children with and without ASD. Children with ASD were found to be significantly less physically active than children without ASD (Δ = -0.62, p < .001). Subgroup analyses revealed significant moderate to large differences in PA by intensity level, age, setting, and measurement methods. Future studies are needed to further explore the underlying mechanisms associated with lower levels of PA among children with ASD.

The Relationship Between Actual and Perceived Motor Competence in Children, Adolescents and Young Adults: A Systematic Review and Meta-analysis.

BACKGROUND: Actual and perceived motor competence are important correlates of various health-related behaviors. As such, numerous studies have examined the association between both constructs in children and adolescents. OBJECTIVES: The first aim of this review and meta-analysis was to systematically examine, analyze and summarize the scientific evidence on the relationship between actual and perceived motor competence (and by extension more general physical self-perception) in children, adolescents and young adults with typical and atypical development. The second aim was to examine several a priori determined potential moderators (i.e., age, sex, and developmental status of study participants, as well as level of alignment between measurement instruments) of the relationship between actual motor competence and perceived motor competence/physical self-perception. DESIGN: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and was registered with PROSPERO on August 21st 2017. DATA SOURCES: A systematic literature search of five electronic databases (i.e., MEDLINE, SPORTDiscus, Web of Science, PsycINFO and EMBASE) with no date restrictions was conducted. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligibility criteria included (1) a study sample of youth aged 3-24 years, (2) an assessment of actual motor competence and perceived motor competence/physical self-perception, and (3) a report of the association between both, using a cross-sectional, longitudinal, or experimental design. Only original articles published in peer-reviewed journals with at least the title and abstract in English were considered. ANALYSES: Meta-analyses were conducted by type of actual motor competence (i.e., overall motor competence, locomotor, object control, stability/balance and sport-specific competence) through univariate and multivariable random-effects meta-regression and clustered random-effects meta-regression models. RESULTS: Of the 1643 articles screened, 87 were included for the qualitative review, while 69 remained for the final meta-analyses. All included studies had some risk of bias with only 15% meeting five of the six examined criteria. Significant (p < 0.001) pooled effects were found for overall motor competence (N = 54; r = 0.25; 95% CI [0.20, 0.29]), locomotor (N = 45; r = 0.19; 95% CI [0.13, 0.25]), object control (N = 50; r = 0.22; 95% CI [0.17, 0.27]), stability/balance (N = 8; r = 0.21; 95% CI [0.12, 0.30]), and sport-specific competence (N = 8; r = 0.46; 95% CI [0.28, 0.61]). None of the hypothesized moderators significantly influenced the relationship between actual motor competence and perceived motor competence/physical self-perception. CONCLUSIONS: The strength of the association between actual motor competence and perceived motor competence/physical self-perception in youth is low to moderate, with current data demonstrating that the strength of association does not differ by age, sex, developmental status, or alignment between measurement instruments. However, this review highlights the lack of clarity on the relationship between actual motor competence and perceived motor competence/physical self-perception. Future research should address issues surrounding the design of studies and measurement of actual motor competence and perceived motor competence/physical self-perception as well as explore other potential confounding variables (i.e., product- versus process-oriented assessments, race, culture) that might affect the relationship between these two constructs.

Ischemia reperfusion injury, KATP channels, and exercise-induced cardioprotection against apoptosis.

Exercise is a potent stimulus against cardiac ischemia reperfusion (IR) injury, although the protective mechanisms are not completely understood. The study purpose was to examine whether the mitochondrial or sarcolemmal ATP-sensitive potassium channel (mito K(ATP) or sarc K(ATP), respectively) mediates exercise-induced cardioprotection against post-IR cell death and apoptosis. Eighty-six, 4-mo-old male Sprague Dawley rats were randomly assigned to treadmill exercise (Ex; 30 m/min, 3 days, 60 min, ∼70 maximal oxygen uptake) and sedentary (Sed) treatments. Rats were exposed to regional cardiac ischemia (50 min) and reperfusion (120 min) or Sham (170 min; no ligation) surgeries. Exercise subgroups received placebo (saline), 5-hydroxydecanoate (5HD; 10 mg/kg ip), or HMR1098 (10 mg/kg ip) to inhibit mito K(ATP) or sarc K(ATP) channel. Comprehensive outcome assessments included post-IR ECG arrhythmias, cardiac tissue necrosis, redox perturbations, and autophagy biomarkers. No arrhythmia differences existed between exercised and sedentary hearts following extended-duration IR (P < 0.05). The sarc K(ATP) channel was confirmed essential (P = 0.002) for prevention of antinecrotic tissue death with exercise (percent infarct, Sed = 42%; Ex = 20%; Ex5HD = 16%; ExHMR = 42%), although neither the mito K(ATP) (P = 0.177) nor sarc K(ATP) (P = 0.274) channel provided post-IR protection against apoptosis (terminal deoxynucleotidyl transferase deoxy UTP-mediated nick-end labeling-positive nuclei/mm(2), Sham = 1.8 ± 0.5; Sed = 19.4 ± 6.7; Ex = 7.5 ± 4.6; Ex5HD = 14.0 ± 3.9; ExHMR = 11.1 ± 1.8). Exercise preconditioning also appears to preserve basal autophagy levels, as assessed by Beclin 1 (P ≤ 0.001), microtubule-associated protein-1 light-chain 3B ratios (P = 0.020), and P62 (P ≤ 0.001), in the hours immediately following IR. Further research is needed to better understand these findings and corresponding redox changes in exercised hearts.

Mitochondrial KATP channel inhibition blunts arrhythmia protection in ischemic exercised hearts.

The mechanisms responsible for anti-arrhythmic protection during ischemia-reperfusion (IR) in exercised hearts are not fully understood. The purpose of this investigation was to examine whether the ATP-sensitive potassium channels in the mitochondria (mito K(ATP)) and sarcolemma (sarc K(ATP)) provide anti-arrhythmic protection in exercised hearts during IR. Male Sprague-Dawley rats were randomly assigned to cardioprotective treadmill exercise or sedentary conditions before IR (I = 20 min, R = 30 min) in vivo. Subsets of exercised animals received pharmacological inhibitors for mito K(ATP) (5-hydroxydecanoate) or sarc K(ATP) (HMR1098) before IR. Blinded analysis of digital ECG tracings revealed that mito K(ATP) inhibition blunted the anti-arrhythmic effects of exercise, while sarc K(ATP) inhibition did not. Endogenous antioxidant enzyme activities for total, CuZn, and Mn superoxide dismutase, catalase, and glutathione peroxidase from ischemic and perfused ventricular tissue were not mitigated by IR, although oxidative stress was elevated in sedentary and mito K(ATP)-inhibited hearts from exercised animals. These findings suggest that the mito K(ATP) channel provides anti-arrhythmic protection as part of exercise-mediated cardioprotection against IR. Furthermore, these data suggest that the observed anti-arrhythmic protection may be associated with preservation of redox balance in exercised hearts.