Comparing the validity and output of the GT1M and GT3X accelerometer in 5- to 9-year-old children

The purpose of this study was to compare the validity and output of the biaxial ActiGraph GT1M and the triaxial GT3X (ActiGraph, LLC, Pensacola, FL, USA)accelerometer in 5- to 9-year-old children. Thirty-two children wore the two monitors while their energy expenditure was measured with indirect calorimetry. They performed four locomotor and four play activities in an exercise laboratory and were further measured during 12 minutes of a sports lesson. Validity evidence in relation to indirect calorimetry was examined with linear regression equations applied to the laboratory data. During the sports lessons predicted energy expenditure according to the regression equations was compared to measured energy expenditure with the Wilcoxon-signed rank test and the Spearman correlation. To compare the output, agreement between counts of the two monitors during the laboratory activities was assessed with Bland-Altman plots. The evidence of validity was similar for both monitors. Agreement between the output of the two monitors was good for vertical counts (mean bias = −14 ± 22 counts) but not for horizontal counts (−17 ± 32 counts). The current results indicate that the two accelerometer models are able to estimate energy expenditure of a range of physical activities equally well in young children. However, they show output differences for movement in the horizontal direction.

Fructose and Galactose Enhance Post-Exercise Human Liver Glycogen Synthesis

Both liver and muscle glycogen stores play a fundamental role in exercise and fatigue, but the effect of different CHO sources on liver glycogen synthesis in humans is unclear. The aim was to compare the effect of maltodextrin (MD) drinks containing galactose, fructose, or glucose on postexercise liver glycogen synthesis.

Secondary prevention through cardiac rehabilitation: physical activity counselling and exercise training: key components of the position paper from the Cardiac Rehabilitation Section of the European Association of Cardiovascular Prevention and Rehabilitation

Cardiac patients after an acute event and/or with chronic heart disease deserve special attention to restore their quality of life and to maintain or improve functional capacity. They require counselling to avoid recurrence through a combination of adherence to a medication plan and adoption of a healthy lifestyle. These secondary prevention targets are included in the overall goal of cardiac rehabilitation (CR). Cardiac rehabilitation can be viewed as the clinical application of preventive care by means of a professional multi-disciplinary integrated approach for comprehensive risk reduction and global long-term care of cardiac patients. The CR approach is delivered in tandem with a flexible follow-up strategy and easy access to a specialized team. To promote implementation of cardiac prevention and rehabilitation, the CR Section of the EACPR (European Association of Cardiovascular Prevention and Rehabilitation) has recently completed a Position Paper, entitled 'Secondary prevention through cardiac rehabilitation: A condition-oriented approach'. Components of multidisciplinary CR for seven clinical presentations have been addressed. Components include patient assessment, physical activity counselling, exercise training, diet/nutritional counselling, weight control management, lipid management, blood pressure monitoring, smoking cessation, and psychosocial management. Cardiac rehabilitation services are by definition multi-factorial and comprehensive, with physical activity counselling and exercise training as central components in all rehabilitation and preventive interventions. Many of the risk factor improvements occurring in CR can be mediated through exercise training programmes. This call-for-action paper presents the key components of a CR programme: physical activity counselling and exercise training. It summarizes current evidence-based best practice for the wide range of patient presentations of interest to the general cardiology community.

Acclimatization improves submaximal exercise economy at 5533m

We tested whether the better subjective exercise tolerance perceived by mountaineers after altitude acclimatization relates to enhanced exercise economy. Thirty-two mountaineers performed progressive bicycle exercise to exhaustion at 490 m and twice at 5533 m (days 6–7 and day 11), respectively, during an expedition to Mt. Muztagh Ata. Maximal work rate (Wmax) decreased from mean ± SD 356 ± 73 watts at 490 m to 191 ± 49 watts and 193 ± 45 watts at 5533 m, days 6–7 and day 11, respectively; corresponding maximal oxygen uptakes (VO2max) were 50.7 ± 9.5, 26.3 ± 5.6, 24.7 ± 7.0 mL/min/kg (P = 0.0001 5533 m vs 490 m). On days 6–7 (5533 m), VO2 at 75% Wmax (152 ± 37 watts) was 1.75 ± 0.45 L/min, oxygen saturation 68 ± 8%. On day 11 (5533 m), at the same submaximal work rate, VO2 was lower (1.61 ± 0.47 L/min, P < 0.027) indicating improved net efficiency; oxygen saturation was higher (74 ± 7%, P < 0.0004) but ratios of VO2 to work rate increments remained unchanged. On day 11, mountaineers climbed faster from 4497 m to 5533 m than on days 5–6 but perceived less effort (visual analog scale 50 ± 15 vs 57 ± 20, P = 0.006) and reduced symptoms of acute mountain sickness. We conclude that the better performance and subjective exercise tolerance after acclimatization were related to regression of acute mountain sickness and improved submaximal exercise economy because of lower metabolic demands for non-external work-performing functions.

Citizen science reveals unexpected continental-scale evolutionary change in a model organism

Organisms provide some of the most sensitive indicators of climate change and evolutionary responses are becoming apparent in species with short generation times. Large datasets on genetic polymorphism that can provide an historical benchmark against which to test for recent evolutionary responses are very rare, but an exception is found in the brown-lipped banded snail (Cepaea nemoralis). This species is sensitive to its thermal environment and exhibits several polymorphisms of shell colour and banding pattern affecting shell albedo in the majority of populations within its native range in Europe. We tested for evolutionary changes in shell albedo that might have been driven by the warming of the climate in Europe over the last half century by compiling an historical dataset for 6,515 native populations of C. nemoralis and comparing this with new data on nearly 3,000 populations. The new data were sampled mainly in 2009 through the Evolution MegaLab, a citizen science project that engaged thousands of volunteers in 15 countries throughout Europe in the biggest such exercise ever undertaken. A known geographic cline in the frequency of the colour phenotype with the highest albedo (yellow) was shown to have persisted and a difference in colour frequency between woodland and more open habitats was confirmed, but there was no general increase in the frequency of yellow shells. This may have been because snails adapted to a warming climate through behavioural thermoregulation. By contrast, we detected an unexpected decrease in the frequency of Unbanded shells and an increase in the Mid-banded morph. Neither of these evolutionary changes appears to be a direct response to climate change, indicating that the influence of other selective agents, possibly related to changing predation pressure and habitat change with effects on micro-climate.

Gender-specific usage of intramyocellular lipids and glycogen during exercise

PURPOSE: Gender-specific differences in substrate utilization during exercise have been reported, typically such that women rely more on fat than men. This study investigated whether gender differences exist in the utilization of intramyocellular lipids (IMCL) and glycogen. METHODS: IMCL and glycogen, as well as total fat and carbohydrate (CHO) oxidation were measured in nine males and nine females before, during, and after an endurance exercise. The trained subjects exercised on a bicycle ergometer at 50% maximal workload for 3 h. IMCL and glycogen were determined in the thigh by magnetic resonance spectroscopy. Oxygen uptake (VO(2)) and carbon dioxide production were determined by open circuit spirometry to calculate total fat and CHO oxidation. Relative power output, percent of maximum heart rate, VO(2peak), and respiratory exchange ratio were the same. RESULTS: Average fat oxidation was the same, whereas CHO oxidation was significantly higher in males compared with females. The relative contribution of these fuels to total energy used were similar in males and females. Males and females depleted IMCL and glycogen significantly (P < 0.001) during the 3-h exercise. IMCL levels at rest (P < 0.05) and its depletion during exercise (P < 0.001) were significantly higher in males compared with females, whereas glycogen was stored and used in the same range by both genders. CONCLUSION: During this 3-h exercise, energy supplies from fat and CHO were similar in both genders, and males as well as females reduced their IMCL stores significantly. The larger contribution of IMCL during exercise in males compared with females could either be a result of gender-specific substrate selection, or different long-term training habit.

Eccentric exercise in coronary patients: central hemodynamic and metabolic responses

With lengthening (eccentric) muscle contractions, the magnitude of locomotor-muscle mass and strength increase has been demonstrated to be greater compared with shortening (concentric) muscle contractions. In healthy subjects, energy demand and heart rate responses with eccentric exercise are small relative to the amount of muscle force produced. Thus, eccentric exercise may be an attractive alternative to resistance exercise for patients with limited cardiovascular exercise tolerance.

The effect of aerobic exercise on intrahepatocellular and intramyocellular lipids in healthy subjects

BACKGROUND Intrahepatocellular (IHCL) and intramyocellular (IMCL) lipids are ectopic lipid stores. Aerobic exercise results in IMCL utilization in subjects over a broad range of exercise capacity. IMCL and IHCL have been related to impaired insulin action at the skeletal muscle and hepatic level, respectively. The acute effect of aerobic exercise on IHCL is unknown. Possible regulatory factors include exercise capacity, insulin sensitivity and fat availability subcutaneous and visceral fat mass). AIM To concomitantly investigate the effect of aerobic exercise on IHCL and IMCL in healthy subjects, using Magnetic Resonance spectroscopy. METHODS Normal weight, healthy subjects were included. Visit 1 consisted of a determination of VO2max on a treadmill. Visit 2 comprised the assessment of hepatic and peripheral insulin sensitivity by a two-step hyperinsulinaemic euglycaemic clamp. At Visit 3, subcutaneous and visceral fat mass were assessed by whole body MRI, IHCL and IMCL before and after a 2-hours aerobic exercise (50% of VO(2max)) using ¹H-MR-spectroscopy. RESULTS Eighteen volunteers (12M, 6F) were enrolled in the study (age, 37.6±3.2 years, mean±SEM; VO(2max), 53.4±2.9 mL/kg/min). Two hours aerobic exercise resulted in a significant decrease in IMCL (-22.6±3.3, % from baseline) and increase in IHCL (+34.9±7.6, % from baseline). There was no significant correlation between the exercise-induced changes in IMCL and IHCL and exercise capacity, subcutaneous and visceral fat mass and hepatic or peripheral insulin sensitivity. CONCLUSIONS IMCL and IHCL are flexible ectopic lipid stores that are acutely influenced by physical exercise, albeit in different directions. TRIAL REGISTRATION ClinicalTrial.gov NCT00491582.

Influence of physical activity and acute exercise on cognitive performance and saliva testosterone in preadolescent school children

We investigated whether the chronic physical activity participation had an impact on the acute effects of a short bout of 12 min of intensive physical activity on cognitive performance and testosterone concentration in primary school students (n = 42, mean age = 9.69, SD = .44; experimental group (EG), n = 27; control group (CG), n = 15). Furthermore, we looked for associations between testosterone concentration and cognitive performance. After the intervention, participants of the EG showed better cognitive performances as compared to the CG. We further observed a significant group (EG, CG) test (pre, post) activity level (high, low) interaction. Post hoc pairwise comparisons revealed that after acute physical activity the testosterone concentration was diminished only in habitually low active children. The results indicate that intensive physical activity only attenuates the reactivity of the hypothalamic-pituitary-gonadal axis in habitually low active preadolescents, but had a beneficial effect on cognitive performance for all participants independent of their physical activity level and testosterone.

The effect of acute exercise and psychosocial stress on fine motor skills and testosterone concentration in the saliva of high school students

Little is known about the influence of different stressors on fine motor skills, the concentration of testosterone (T), and their interaction in adolescents. Therefore, 62 high school students aged 14–15 years were randomly assigned to two experimental groups (exercise, psychosocial stress) and a control group. Exercise stress was induced at 65–75% of the maximum heart rate by running for 15 minutes (n = 24). Psychosocial stress was generated by an intelligence test (HAWIK- IV), which was uncontrollable and characterized by social-evaluative-threat to the students (n=21). The control group followed was part of a regular school lesson with the same duration (n = 28). Saliva was collected after a normal school lesson (pre-test) as well as after the intervention/control period (post-test) and was analyzed for testosterone. Fine motor skills were assessed pre- and post-intervention using a manual dexterity test (Flower Trail) from the Movement Assessment Battery for Children-2. A repeated measure ANCOVA including gender as a covariate revealed a significant group by test interaction, indicating an increase in manual dexterity only for the psychosocial stress group. Correlation analysis of all students shows that the change of testosterone from pre- to post-test was directly linked (r = 2.31, p = .01) to the changes in manual dexterity performance. Participants showing high increases in testosterone from pre- to post-test made fewer mistakes in the fine motor skills task. Findings suggest that manual dexterity increases when psychosocial stress is induced and that improvement of manual dexterity performance corresponds with the increase of testosterone.

Effects of exercise on anxiety and depression disorders: Review of meta-analyses and neurobiological mechanisms

Anxiety and depression are the most frequently diagnosed psychological diseases showing a high co-morbidity. They have a severe impact on the lives of the persons concerned. Many meta-analytical studies suggested a positive anxiolytic and depression reducing effect of exercise programs. The aim of the present article is to synthesize metaanalyses on the effects of exercise on anxiety and depression and to describe average effect sizes. For this purpose 37 meta-analyses were included reporting 50 effect sizes for anxiety scores of 42,264 participants and depression scores of 48,207 persons. The average documented anxiolytic effect of exercise in these reviews was small, 0.34. In contrast, the effect of exercise on depression was significantly higher and at a moderate level, 0.56. Data of randomized controlled trials suggest higher sizes for the effect of exercise on anxiety and depression leading to increases up to moderate and large effects, respectively. Additionally, exercise seems to be more beneficial for patients compared to participants within a nonclinical, normal range of psychological disease. Especially for the effect of exercise on anxiety, more high quality meta-analyses of randomized controlled trials are needed. Finally, possible neurobiological explanations are suggested for the positive effect of exercise on psychological disorders like anxiety and depression.

Subjective well-being and exercise in the second halt of life: a critical review of theoretical approaches

Research has shown repeatedly that the “feeling better” effect of exercise is far more moderate than generally claimed. Examinations of subgroups in secondary analyses also indicate that numerous further variables influence this relationship. One reason for inconsistencies in this research field is the lack of adequate theoretical analyses. Well-being output variables frequently possess no construct definition, and little attention is paid to moderating and mediating variables. This article integrates the main models in an overview and analyzes how secondary analyses define well-being and which areas of the construct they focus on. It then applies a moderator and/or mediator framework to examine which person and environmental variables can be found in the existing explanatory approaches in sport science and how they specify the influence of these moderating and mediating variables. Results show that the broad understanding of well-being in many secondary analyses makes findings difficult to interpret. Moreover, physiological explanatory approaches focus more on affective changes in well-being, whereas psychological approaches also include cognitive changes. The approaches focus mostly on either physical or psychological person variables and rarely combine the two, as in, for example, the dual-mode model. Whereas environmental variables specifying the treatment more closely (e.g., its intensity) are comparatively frequent, only the social support model formulates variables such as the framework in which exercise is presented. The majority of explanatory approaches use simple moderator and/or mediator models such as the basic mediated (e.g., distraction hypothesis) or multiple mediated (e.g., monoamine hypotheses) model. The discussion draws conclusions for future research.