ROBERTSON, R. J., F. L. GOSS, N. F. BOER, J. A. PEOPLES, A. J. FOREMAN, I. M. DABAYEBEH, N. B. MILLICH, G. BALASEKARAN, S. E. RIECHMAN, J. D. GALLAGHER, and T. THOMPKINS. Children’s OMNI Scale of Perceived Exertion: mixed gender and race validation. Med. Sci. Sports Exerc., Vol. 32, No. 3, pp. 452–458, 2000. The newly developed Children’s OMNI Scale of Perceived Exertion (category range: 0 to 10) was validated using separate cohorts of female and male, African American and white subjects. Each of the four cohorts contained 20 clinically normal, nonobese children, 8–12 yr of age. A cross-sectional, perceptual estimation paradigm using a single multi-stage cycle ergometer test protocol was used. Oxygen uptake (V̇O2; mL·min−1), heart rate (HR; beats·min−1) and ratings of perceived exertion for the overall body (RPE-Overall), legs (RPE-Legs), and chest (RPE-Chest) were determined at the end of each continuously administered 3-min power output (PO) (i.e., 25, 50, 75, and 100 W) test stage. The range of responses over the four POs for all cohorts was V̇O2: 290.8 to 1204.0 mL·min−1; HR: 89.2 to 164.4 beats·min−1; and RPE-Overall, RPE-Legs, and RPE-Chest: 0.85 to 9.1. First-order correlation and linear regression analyses were performed for each cohort separately and the total sample using a repeated measures paradigm over the four POs. For all correlation/regression paradigms RPE-Overall, RPE-Legs, and RPE-Chest distributed as a positive linear function of both V̇O2 and HR; r = 0.85 to 0.94;P < 0.01. Differences between RPE-Overall, RPE-Legs, and RPE-Chest were examined with ANOVA for the repeated measures paradigm. RPE-Legs was higher (P < 0.01) than RPE-Chest and RPE-Overall at 25, 50, 75, and 100 W. RPE-Chest did not differ from RPE-Overall at 25 and 50 W but was lower (P < 0.01) than RPE-Overall at 75 and 100 W. The psycho-physiological responses provide validity evidence for use of the Children’s OMNI Scale over a wide range of dynamic exercise intensities.

Interleukin-15 (IL-15) is an anabolic cytokine that is produced in skeletal muscle and directly affects muscle anabolism in animal and in vitro models. The contribution of IL-15 variability in muscle responses to 10 wk of resistance exercise training in young men and women was examined by measuring acute and chronic changes in IL-15 protein in plasma and characterizing genetic variation in the IL-15 receptor-α gene (IL15RA). Participants trained 3 days a week at 75% of one repetition maximum, performing three sets (6–10 repetitions) of 13 resistance exercises. Plasma IL-15 protein was significantly increased ( P < 0.05) immediately after acute resistance exercise but did not change with training and was not associated with variability in muscle responses with training. A single nucleotide polymorphism in exon 7 of IL15RA was strongly associated with muscle hypertrophy and accounted for 7.1% of the variation in regression modeling. A polymorphism in exon 4 was also independently associated with muscle hypertrophy and accounted for an additional 3.5% of the variation in hypertrophy. These results suggest that IL-15 is an important mediator of muscle mass response to resistance exercise training in humans and that genetic variation in IL15RA accounts for a significant proportion of the variability in this response.

The aim of this study was to predict indoor rowing performance in 12 competitive female rowers (age 21.3 - 3.6 years, height 1.68 - 0.54 m, body mass 67.1 - 11.7 kg; mean - s ) using a 30 s rowing sprint, maximal oxygen uptake and the blood lactate response to submaximal rowing. Blood lactate and oxygen uptake ( V O 2 ) were measured during a discontinuous graded exercise test on a Concept II rowing ergometer incremented by 25 W for each 2 min stage; the highest V O 2 measured during the test was recorded as V O 2max (mean = 3.18 - 0.35 l· min -1 ). Peak power (380 - 63.2 W) and mean power (368 - 60.0 W) were determined using a modified Wingate test protocol on the Concept II rowing ergometer. Rowing performance was based on the results of the 2000 m indoor rowing championship in 1997 (466.8 - 12.3 s). Laboratory testing was performed within 3 weeks of the rowing championship. Submitting mean power (Power), the highest and lowest five consecutive sprint power outputs (Maximal and Minimal), percent fatigue in the sprint test (Fatigue), V O 2max (l· min -1 ), V O 2max (ml·kg -1 ·min -1 ), V O 2 at the lactate threshold, power at the lactate threshold (W), maximal lactate concentration, lactate threshold (percent V O 2max ) and V E max (l·min -1 ) to a stepwise multiple regression analysis produced the following model to predict 2000 m rowing performance: Time 2000 =- 0.163 (Power)14.213 ·( V O 2max l· min -1 ) + 0.738· (Fatigue) + 567.259 ( R 2 = 0.96, standard error = 2.89). These results indicate that, in the women studied, 75.7% of the variation in 2000 m indoor rowing performance time was predicted by peak power in a rowing Wingate test, while V O 2max and fatigue during the Wingate test explained an additional 12.1% and 8.2% of the variance, respectively.

OBJECTIVE: African-Americans are at increased risk for type 2 diabetes. We have previously demonstrated that African-American children are hyperinsulinemic and insulin resistant compared with their white American peers. The aim of the present investigation was to assess the impact of family history of type 2 diabetes on insulin sensitivity in African-American children. RESEARCH DESIGN AND METHODS: A total of 13 prepubertal healthy children with negative family history (FH-) and 9 with positive family history (FH+) of type 2 diabetes underwent a 3-h hyperinsulinemic (40 mU x m(-2) x min(-1))-euglycemic clamp study to assess insulin sensitivity. The groups were comparable for age, pubertal status, total body adiposity determined by dual-energy X-ray absorptiometry, abdominal adiposity assessed by computed tomography scan at the level of L4-5 lumbar vertebra, and physical fitness measured by maximal oxygen consumption (VO2max). RESULTS: The FH+, compared with the FH-, group had lower insulin-stimulated glucose disposal (10.9+/-1.2 vs. 14.2+/-0.9 mg x kg(-1) x min(-1), P = 0.035) and lower nonoxidative glucose disposal (5.7+/-0.8 vs. 8.3+/-0.6 mg x kg(-1) x min(-1), P = 0.015), with no differences in rates of glucose oxidation, fat oxidation, or insulin-mediated free fatty acid suppression. Fasting hepatic glucose production assessed with [6,6-2H2]glucose and basal rates of glucose and fat oxidation were not different between the two groups. CONCLUSIONS: These data suggest that in African-American children, family history of type 2 diabetes is a risk factor for insulin resistance. These children manifest important metabolic alterations, including impaired insulin-stimulated total and nonoxidative glucose disposal early in the first decade of life. We propose that this familial tendency, combined with environmental influences, could lead to type 2 diabetes decades later.

Despite the global impact of COVID-19, studies comparing the effects of COVID-19 on population mental health across countries are sparse. This study aimed to compare anxiety and depression symptoms during the COVID-19 lockdown among adults from 11 countries and to examine their associations with country-level COVID-19 factors and personal COVID-19 exposure. A cross-sectional survey was conducted among adults (≥18 years) in 11 countries (Brazil, Bulgaria, China, India, Ireland, North Macedonia, Malaysia, Singapore, Spain, Turkey, United States). Mental health (anxiety, depression, resilient coping, hope) and other study data were collected between June–August 2020. Of the 13,263 participants, 62.8% were female and 51.7% were 18–34 years old. Participants living in Brazil had the highest anxiety and depression symptoms while participants living in Singapore had the lowest. Greater personal COVID-19 exposure was associated with increased anxiety and depression symptoms, but country-level COVID-19 factors were not. Higher levels of hope were associated with reduced anxiety and depression; higher levels of resilient coping were associated with reduced anxiety but not depression. Substantial variations exist in anxiety and depression symptoms across countries during the COVID-19 lockdown, with personal COVID-19 exposure being a significant risk factor. Strategies that mitigate COVID-19 exposure and enhance hope and resilience may reduce anxiety and depression during global emergencies.

Classroom-based physical activity (PA) interventions have received considerable attention due to improvements seen in academic achievement, classroom behaviors, and attitude toward PA. The purpose of this study was to evaluate the effectiveness of the Brain Breaks® Physical Activity Solutions in changing children’s attitudes toward PA. Students (N = 3036) aged 8–11 years from schools in Croatia, Lithuania, Macedonia, Poland, Romania, Serbia, South Africa, and Turkey were randomly assigned to either a control or an experimental group. The experimental group received Brain Breaks® videos during classroom sessions throughout the four months of intervention. Student attitudes toward PA were measured using the Attitudes toward Physical Activity Scale (APAS) before and after the intervention. Repeated measures ANOVA indicated a time interaction effect for all APAS variables except fitness. Time-by-group interaction effects with different effect sizes were found for most APAS variables, with the greatest gain effect noted in the experimental group for self-efficacy, followed by learning from the videos concerning PA benefits, exercise importance, and enjoyment from engaging in PA. This study provides evidence supporting Brain Breaks® in terms of learning experience, attitudes towards PA, and personal motivation. Using exercise videos is recommended as an interactive, technology-based PA solution that can be easily integrated into the school setting.