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Backround: Low physical activity and high sedentary behaviour is a concern already during preschool period with potential impacts on children's future cognitive health in school. However, longitudinal data regarding the associations of physical activity, sedentary time and cognition at young age are limited, thus the aim of this study was to investigate whether objectively monitored moderate-to-vigorous physical activity (MVPA) and sedentary time at preschool age are related to cognitive skills in the first grade of school among boys and girls., Methods: Participants were boys (n = 50, aged 6.6 ± 0.5 years) and girls (n = 41, aged 6.5 ± 0.5 years) from thirteen kindergartens and the same children after entering first grade of school. MVPA and sedentary time were measured by means of accelerometer. Modified Boehm-3 test was used to assess cognitive skills., Results: MVPA in preschool was unrelated to perceptual, conceptual or verbal skills in school in boys and girls. In boys, higher sedentary time in preschool was associated with higher conceptual skills (β = 0.461, p = 0.040) in school after adjustment for age, baseline conceptual skills, accelerometer wear time and parental education., Conclusions: In conclusion, higher sedentariness in preschool is associated with higher conceptual skills in grade one among boys but not in girls. MVPA in preschool is unrelated to cognitive skills in school among boys and girls. The results indicate that perceptual, conceptual and verbal skills in first grade of school are not affected by MVPA level in preschool neither among boys, nor girls. Regarding conceptual skills in school, boys might benefit from sedentary activities during preschool period., Competing Interests: Declarations. Ethics approval and consent to participate: This study complies with the Declaration of Helsinki and was performed according to the Research Ethics Committee of the University of Tartu, Estonia (reference 254/T-13 and 266/T-8, date 19 January 2015 and 16 January 2017, respectively) approval. Informed consent to participate was obtained from the parents or legal guardians of any participant. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children's and adolescents' (5-17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions., Methods: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders' top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country., Results: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally., Conclusions: The Global Matrix 4.0 represents the largest compilation of children's and adolescents' PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

This study investigated longitudinal relationships between physical activity (PA), fitness and cognitive performance at early years. In total, 147 children at the age of 6.6 and 7.6 years participated in the study. PA and sedentary behaviour (SB) were registered with accelerometer. Skinfold thickness measurements were used to assess body composition. Children's cardiorespiratory fitness (CRF), muscular strength and speed-agility fitness was assessed using PREFIT fitness test battery and static balance by EUROFIT test battery. Cognitive skills were measured with modified Boehm-3 test. Linear regression analyses showed that PA at the age of 6.6 years was positively, while SB was negatively associated with the conceptual skills at the age of 7.6 years after adjusting for confounders. Positive associations were observed between CRF, lower-limbs strength relative to fat-free mass, static balance at the age of 6.6 years with perceptual skills at 7.6 years in unadjusted analysis. PA and fitness were not associated with verbal abilities. Physically active lifestyle and CRF, relative explosive strength of the lower limbs, balance at 6.6 years in kindergarten predict conceptual and perceptual skills, but does not predict verbal abilities 1 year later at first grade in school. SB affects negatively conceptual skills.

Little is known about the longitudinal trajectories and associations regarding physical activity (PA), physical fitness (PF), and cognitive skills in childhood. Accelerometer-based PA, sedentary behavior (SB), PF, and cognitive skills were measured in Estonian children ( n = 147) in kindergarten (6.6 years) and again at school (7.6 years). Children were subgrouped into lower and upper quartiles by their moderate-to-vigorous PA (MVPA) at 6.6 years. Children in the upper quartile had lower SB, higher PA, and greater muscular strength. Attending school, MVPA in the lower quartile improved. In both subgroups, most strength values and cognitive skills improved, while balance deteriorated in first grade. In the upper quartile, a greater MPA at 6.6 years predicted lower perceptual skills at 7.6 years. A greater SB at 6.6 years predicted higher verbal skills, light and moderate PA and MVPA, and lower verbal skills at 7.6 years after taking into account confounding factors such as the child's sex, age, awake wear time (AWT), maternal education, and/or child's sports participation. A vigorous PA at 6.6 years predicted perceptual (in upper quartile) or verbal (in lower quartile) skills at 7.6 years after controlling for similar confounders. No correlation for PF at 6.6 years and cognitive skills at 7.6 years existed; after adjusting for the above-mentioned confounders relative to upper/lower-limb strength, the 4 × 10 m shuttle run results predicted higher perceptual or verbal skills; static balance and cardiorespiratory fitness predicted lower verbal skills. Cardiorespiratory fitness predicted higher perceptual skills after controlling for sex, age, and AWT. Overall, PA and strength were constantly better and SB lower in the upper quartile, yet the lower quartile demonstrated improved MVPA in first grade, and both subgroups increased most components of their strength and cognitive skills in first grade. Higher levels of VPA at kindergarten predicted either better perceptual or verbal skills in first grade after controlling for confounders; the opposite associations were found for other PA levels and cognitive skills in the higher quartile. PF components at kindergarten predicted either superior or inferior cognitive skills in first grade after adjusting for confounders.

Objectives: Sclerostin is an important regulator of bone mass involving the Wnt/β-catenin signalling pathway. Relatively few studies have investigated the relationships of circulating sclerostin levels with adiposity-related and muscle-related biochemical factors in individuals with increased energy metabolism. The aim of this study was to investigate the associations of circulating sclerostin with adipokines, myokines, osteokines and body composition values in lean adolescent females with increased physical activity., Methods: A total of 73 adolescent females who were physically active and aged 14-18 years old participated in the study. Sclerostin, leptin, resistin, tumour necrosis factor (TNF)-α, interleukin (IL)-6, irisin, osteocalcin, C-terminal telopeptide of type I collagen (CTx), insulin-like growth factor (IGF)-1 and insulin were obtained from fasting blood samples. Body composition was measured by dual-energy X-ray absorptiometry (DXA) and analyzed for body fat mass, lean body mass, bone mineral content and muscle mass., Results: Serum sclerostin (117.9 ± 60.3 pg/mL) was correlated with age, age at menarche, body fat, muscle mass, training activity, leptin, TNF-α, irisin, osteocalcin, CTx and IGF-1. Multivariate linear regression analysis demonstrated that fat mass ( β = 0.434; p = 0.001), leptin ( β = -0.308; p = 0.015), irisin ( β = 0.227; p = 0.024) and CTx ( β = 0.290; p = 0.031) were the most important predictors of serum sclerostin concentration., Conclusions: Bone-derived sclerostin is associated with specific adipokine, myokine and osteokine values in lean adolescent females with increased physical activity. These results suggest that the interactions between bone, adipose and muscle tissues could also be associated with circulating sclerostin concentrations., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

This study examined sclerostin and cytokine responses to an endurance training session in male single sculling rowers. Sixteen highly trained rowers performed a 2-h rowing exercise (distance: 23.8 ± 0.9 km; heart rate: 138 ± 8  beats.min -1 ; intensity: 79.8 ± 2.1% of the anaerobic threshold). Rowing resulted significant increment (p < 0.05) in sclerostin (36%), interleukin (IL)-6 (345%), IL-10 (129%) and monocyte chemoattractant protein-1 (MCP-1) (132%), while increases in irisin (6%) and tumour necrosis factor-α (3%) were not significant (p > 0.05). There was a correlation between the pre-to-post-exercise increase in sclerostin and the distance covered (r = 0.67; p = 0.005) as a marker of energy expenditure, and weekly training volume (r = 0.66; p = 0.005) as a marker of training stress. Post-exercise gain in MCP-1 was the most important predictor of post-exercise gain in sclerostin (β = 0.543; p = 0.040). In conclusion, acute non-impact rowing training session with a total body mode induced increases in sclerostin and also in IL-6, IL-10 and MCP-1 concentrations, while post-exercise gain in MCP-1 was the main determinant of post-exercise gain in sclerostin. Exercise-induced increase in sclerostin could be regarded as a signal for metabolic reaction to the energy cost of acute exercise in rowers.

The purpose of the study was to assess the longitudinal associations of physical activity (PA) with body composition and physical fitness (PF) at the 12-month follow-up during the transition from kindergarten to school in Estonian children aged 6 to 8 years (n = 147). PA and sedentary behavior (SB) were assessed using the accelerometer. Body composition was measured from triceps and subscapular skinfold thicknesses and PF using PREFIT test battery. SB at the mean age of 6.6 year had negative relation with upper and lower body strength and motor fitness at the mean age of 7.6 year in adjusted models. Light PA (LPA) and moderate PA(MPA) at 6.6 year were positively and SB was negatively associated with fat-free mass index (FFMI) at 7.6 year after adjustments for confounders [vigorous PA (VPA), total awake wear time, child's sex, age at measurement]. Substituting 5 min/d of SB at 6.6 year with 5 min of VPA was related to higher FFMI at 7.6 year. In adjusted models, VPA at 6.6 year was positively associated with cardiorespiratory fitness at 7.6 year, greater baseline VPA or moderate-to-vigorous PA (MVPA) predicted greater upper body strength a year later and LPA, MPA, VPA, MVPA at 6.6 year were positively related to lower body strength at follow-up. In adjusted analysis greater VPA at 6.6 year was related to better motor fitness at follow-up. Promoting higher-intensity PA and reducing SB at preschool may have long-term effects on body composition and PF in children at the first grade., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Regular physical activity (PA) has been associated with decreased risk of many chronic diseases and increased longevity among older adults. In addition, ageing has been associated with higher levels of different inflammatory biomarkers while the association between inflammatory biomarkers and PA has remained controversial. The aim of the current investigation was to examine the association between blood biomarkers and objectively assessed PA among a sample of healthy older women with different levels of PA engagement. A total of 81 healthy women were recruited. Study participants were allocated to three groups according to accelerometer-obtained PA data. Body composition was assessed with dual-energy X-ray absorptiometry. Fasting blood samples were collected for the measurement of resistin, leptin, tumour necrosis factor alpha (TNFα) and C-reactive protein (CRP) concentrations. There were no significant differences between groups for resistin, leptin, TNFα and for CRP concentrations; however, higher moderate-to-vigorous physical activity (MVPA) groups tended to have lower level of blood biomarker concentrations. There was a significant negative relationship between resistin and steps per day. Inverse association between leptin and MVPA was significant after controlling for age. In multivariate stepwise linear regression analysis, steps per day were the strongest independent predictor for resistin, whereas for leptin, TNFα and CRP the strongest independent predictor was whole body fat mass. In conclusion, this study demonstrated negative association between resistin concentration and steps per day. Sedentary time and light PA had no relationship with resistin, leptin, TNFα or CRP concentrations.

Background: The aim of this study was to investigate physical fitness and physical activity (PA) of 6-7-year-old children just before entering school according to their sports club (SC) participation and weight status, and to examine possible associations of their body mass index, fat mass and fat-free mass with physical fitness and PA., Methods: A total of 256 preschoolers aged 6 to 7 years participated in the study. Physical fitness was assessed using PREFIT test battery and objective PA by 7 day accelerometry. Body composition was estimated using two skinfold thickness parameters. SC participation and parental data were assessed by questionnaires., Results: Children participating in SC had higher moderate-to-vigorous PA, vigorous PA and cardiorespiratory fitness than children not participating in SC. Overweight children had lower results in cardiorespiratory fitness and all weight-bearing fitness tests, and better results in handgrip strength test in comparison with normal weight children. Significant associations were found between body composition indices and physical fitness tests. PA level was associated with fat-free mass and physical fitness but not with fatness indices., Conclusions: Weight-status and body composition together with PA level were associated with physical fitness level. The differences in physical fitness based more upon weight status than SC participation among 6-7-years old children., Competing Interests: The authors have declared that no competing interests exist.

Background and objectives: Studies indicate that genetic and lifestyle factors influence optimal bone development. Adaptations in bone mineral characteristics related to physical activity (PA) are most often observed in pre- and peri-puberty. Longitudinal associations between bone mineral accrual and objectively measured PA in puberty are poorly understood. The present study aims to investigate whether pubertal PA at different intensities is related to bone mineral characteristics in individuals at 18 years of age. Materials and Methods: Anthropometrics, pubertal stage, bone age and PA by accelerometer were measured in 88 boys at the mean age of 12.1 (T1), 13.1 (T2), 14.0 (T3) and 18.0 years (T4). Different bone mineral parameters were measured by dual-energy X-ray at T4. Stepwise multiple regression analysis was performed to determine the effect of bone age, body mass and PA characteristics on measured bone mineral parameters at 18 years of age. Results: Total PA in puberty together with mean pubertal body mass predicted 35.5% of total body (TB) bone mineral density (BMD), 43.0% of TB less head (LH) bone mineral content (BMC) and 48.1% of BMC/height in individuals at 18 years of age. Vigorous PA and body mass in puberty predicted 43.2% of femoral neck (FN) BMD; bone age at T1, vigorous PA and body mass in puberty predicted 47.3% of FN BMC at 18 years of age. No associations between pubertal PA levels and lumbar spine bone mineral characteristics in individuals at 18 years of age were found. Conclusions: Physical activity in puberty has a significant impact on bone mineral characteristics in individuals at 18 years of age, with total PA being a significant predictor of TB BMD and TB LH BMC as well as BMC/height, whereas vigorous PA is a significant predictor of FN BMD and FN BMC., Competing Interests: The authors declare no conflict of interest.

Purpose: Vigorous physical activity (VPA) has been proven to promote osteogenesis in adolescents; however the specifics of the optimal pattern of frequency and duration of VPA are unknown. The main goal of the present study was to analyze the associations of different length of VPA bouts with bone health., Methods: 180 healthy male adolescents (11-13 years) had their bone mineral content and density assessed by dual-energy X-ray absorptiometry scans at the whole body, femoral neck (FN) and lumbar spine and their physical activity measured by an accelerometer during one week., Results: VPA was the intensity with the strongest associations with bone mineral parameters especially at the FN. Subjects whose longest VPA bout was 5 min or above had higher FN bone mineral density (BMD) than those who did not complete any 5-min bout and these differences were greater with participants who reached 15 consecutive minutes of VPA (>15': 0.977 ± 0.020 g/cm2; 5'-15': 0.907 ± 0.009 g/cm2; <5': 0.876 ± 0.009 g/cm2; all p < 0.05). When comparing the relevance of VPA bouts and volume of physical activity, the group with low volume and having a VPA bout had better FN BMD compared to the group with high volume but no VPA bout. Additionally, the group with both high volume and VPA bout showed better FN BMD than the rest of the groups., Conclusions: VPA may be the most effective activity intensity to improve bone mineral density and content of adolescent boys, with greater benefits if VPA periods either long or frequent., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Accumulating sufficient moderate to vigorous physical activity is recognized as a key determinant of physical, physiological, developmental, mental, cognitive, and social health among children and youth (aged 5-17 y). The Global Matrix 3.0 of Report Card grades on physical activity was developed to achieve a better understanding of the global variation in child and youth physical activity and associated supports., Methods: Work groups from 49 countries followed harmonized procedures to develop their Report Cards by grading 10 common indicators using the best available data. The participating countries were divided into 3 categories using the United Nations' human development index (HDI) classification (low or medium, high, and very high HDI)., Results: A total of 490 grades, including 369 letter grades and 121 incomplete grades, were assigned by the 49 work groups. Overall, an average grade of "C-," "D+," and "C-" was obtained for the low and medium HDI countries, high HDI countries, and very high HDI countries, respectively., Conclusions: The present study provides rich new evidence showing that the situation regarding the physical activity of children and youth is a concern worldwide. Strategic public investments to implement effective interventions to increase physical activity opportunities are needed.

Background: To better understand the childhood physical inactivity crisis, Report Cards on physical activity of children and youth were prepared concurrently in 30 very high Human Development Index countries. The aim of this article was to present, describe, and compare the findings from these Report Cards., Methods: The Report Cards were developed using a harmonized process for data gathering, assessing, and assigning grades to 10 common physical activity indicators. Descriptive statistics were calculated after converting letter grades to interval variables, and correlational analyses between the 10 common indicators were performed using Spearman's rank correlation coefficients., Results: A matrix of 300 grades was obtained with substantial variations within and between countries. Low grades were observed for behavioral indicators, and higher grades were observed for sources of influence indicators, indicating a disconnect between supports and desired behaviors., Conclusion: This analysis summarizes the level and context of the physical activity of children and youth among very high Human Development Index countries, and provides additional evidence that the situation regarding physical activity in children and youth is very concerning. Unless a major shift to a more active lifestyle happens soon, a high rate of noncommunicable diseases can be anticipated when this generation of children reaches adulthood.

Background: Older adults have twice as many disabilities and four times as many physical limitations as people <60 years of age. Positive influence of physical activity to prevent these limitations has been presented in some studies. However, the indispensable combination of physical abilities and body composition parameters to maintain independence in later life and their relationship with physical activity has not been studied thoroughly., Objective: The main aim of this study was to determine possible differences in body composition and mobility parameters among older women with various levels of engagement in physical activity. In addition, the relationships between mobility and distinct levels of physical activity were evaluated in healthy older women., Methods: Eighty-one healthy older women aged from 65 to 91 years participated in this study and were allocated to three groups according to weekly moderate-to-vigorous physical activity (MVPA) time in 10 min bouts: highest MVPA (H-MVPA) (n = 27), middle MVPA (M-MVPA) (n = 40) and lowest MVPA (L-MVPA) (n = 14). Body composition (fat mass [FM] and fat free mass [FFM]) variables were assessed with dual-energy X-ray absorptiometry (DXA), objective physical activity data were collected with accelerometers and mobility tests were carried out to assess static and dynamic balance, lower limbs strength and aerobic capacity., Results: No differences in body composition parameters were observed between studied groups (p > 0.0025). Women in L-MVPA covered significantly shorter distance during the six-minute walk test (6MWT) compared to H-MVPA (p = 0.000) and M-MVPA (p = 0.003) groups, performed timed-up-and-go (TUG) slower compared to H-MVPA group (p = 0.003) and five-times-sit-to-stand (FTSTS) test slower compared to H-MVPA (p = 0.006) and M-MVPA (p = 0.009) groups. There were no differences in body composition and mobility parameters between women in H-MVPA and M-MVPA groups. Regardless of bout duration, MVPA was correlated with mobility (TUG r = -0.47; FTSTS r = -0.37; 6MWT r = 0.53) parameters, whereas no relationships was observed with light physical activity (LPA)., Conclusion: MVPA is associated with body composition and mobility parameters, while LPA is not related to any measured body composition nor mobility parameters. Accordingly, healthy older women could benefit from MVPA to maintain body composition and mobility parameters to preserve independence in later life., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: To investigate the differences in the pattern of changes in serum inflammatory cytokines measured annually over a 24-month period, between less active and more active overweight boys., Participants/methods: In total, 25 pubertal overweight boys were divided by their moderate to vigorous physical activity (MVPA) levels into 2 groups: less active group (LAG; n = 10; MVPA < 60 min/d) and more active group (MAG; n = 15; MVPA > 60 min/d). Physical activity was measured by 7-day accelerometry. Serum concentration of 13 inflammatory cytokines [interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, IL-1α, IL-1β, vascular endothelial growth factor, interferon-γ, tumor necrosis factor-α, monocyte chemotactic protein-1, epidermal growth factor, and C-reactive protein] was measured at baseline (T0), after 12 months (T1), and after 24 months (T2) from fasting blood samples., Results: Serum IL-6 level was significantly higher [LAG: 1.27 (0.86, 1.98) pg/mL; MAG: 0.80 (0.52, 0.84) pg/mL] at T0 and IL-8 level [LAG: 10.26 (8.80, 11.64) pg/mL; MAG: 7.42 (6.10, 9.54) pg/mL] at T2 in LAG compared with MAG. The changes over the study period varied between different inflammatory markers. None of the slopes of any measured markers were statistically different between the LAG and MAG, although the slopes of interferon-γ and IL-10 tended to be different between the groups., Conclusions: The pattern of changes over the study period varied between different inflammatory markers, but these changes were not different between the MVPA groups. More longitudinal studies are needed to investigate whether IL-6, IL-8, IL-10, and interferon-γ would be the choice of inflammatory markers to study the associations between obesity and physical activity in future.

Background: Physical activity, sedentary time, and sleep duration have been associated with body composition among children. The purpose of the present study was to assess the associations of objectively determined daily physical activity, sedentary time, sleep duration and body composition indices in 10-12-year-old children., Methods: Two hundred and eleven schoolchildren (96 boys and 115 girls) aged 10.9 ± 0.7 years participated in this study. Objective physical activity intensity and sedentary levels were measured for seven days by accelerometry. Sleep duration was self-reported. Percentage of body fat, waist-to-height ratio and fat free mass were calculated from measured anthropometric parameters. Multiple linear regression models were used to examine the associations between sleep duration, moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA) level and body composition indices., Results: Boys exceeded girls (p < 0.05) in time spent in MVPA and VPA levels. Only 4.3% of the children met the current daily recommendation of at least 60 min MVPA per day. Sleep duration, MVPA and VPA had a negative association with percentage of body fat and waist-to-height ratio. Vigorous physical activity had a positive association with fat-free mass. Sedentary time had a positive association with percentage of body fat and negative association with fat-free mass., Conclusions: The present study suggests that both sleep duration and MVPA are associated with body composition parameters. Higher levels of MVPA are associated with lower percentage of body fat and waist-to-height ratio regardless of sleep duration. Sedentary time is associated with higher values of percentage of body fat and lower fat-free mass independently of sleep duration.

For The Year that Was-2016, I have selected three papers in the area of growth, maturation, and exercise during youth. The year of 2016 was a successful year and it was not an easy task to highlight the most significant publications in this specific area of pediatric exercise science. The first paper has been chosen because it provides, for the first time, the growth and maturational status of elite junior tennis players belonging to the top eight players in the National rankings in various ages and compares against population norms. It appeared that individual differences in growth and maturation contribute towards the selection of elite junior tennis players in both sexes, with a bias towards these athletes who are comparatively tall and heavy for their age already in younger ages. The second paper is a methodological paper and was selected because it provides a unique perspective on the use of different tracking coefficients to investigate short-term tracking of cardiorespiratory and performance-related physical fitness among adolescents during growth and maturation. Specifically, three distinct statistical approaches were applied in this paper: auto-correlations, mulitilevel modeling corrected tracking values for time-varying covariates and Cohen`s Kappa in order to identify group and individual tracking as well as individuals whose trajectories are unstable across time. This methodological paper demonstrated the importance of the selection of the statistical approach to monitor and describe short-term tracking of cardiorespiratory and performance-related physical fitness variables in adolescents during growth and maturation. The third selected paper provided some evidence that the consequence of physical activity during childhood can be far reaching as physical activity might not only promote health benefits but also have positive effects on adulthood earnings.

Self-report measures of physical activity (PA) are easy to use and popular but their reliability is often questioned. Therefore, the general aim of the present study was to investigate the association of PA questionnaires with accelerometer derived PA, in a sample of adolescent boys. In total, 191 pubertal boys (mean age 14.0 years) completed three self-report questionnaires and wore an accelerometer (ActiGraph GT1M) for 7 consecutive days. The PA questionnaires were: International Physical Activity Questionnaire-Short Form (IPAQ-SF), Tartu Physical Activity Questionnaire (TPAQ), and the Inactivity subscale from Domain-Specific Impulsivity (DSI) scale. All three questionnaires were significantly correlated with accelerometer derived MVPA: the correlations were 0.31 for the IPAQ-SF MVPA, 0.34 for the TPAQ MVPA and -0.29 for the DSI Inactivity scale. Nevertheless, none of the questionnaires can be used as a reliable individual-level estimate of MVPA in male adolescents. The boys underreported their MVPA in IPAQ-SF as compared to accelerometer-derived MVPA (respective averages 43 and 56 minutes); underreporting was more marked in active boys with average daily MVPA at least 60 minutes, and was not significant in less active boys. Conversely, MVPA index from TPAQ overestimated the MVPA in less active boys but underestimated it in more active boys. The sedentary time reported in IPAQ-SF was an underestimate as compared to accelerometer-derived sedentary time (averages 519 and 545 minutes, respectively)., Competing Interests: The authors have declared that no competing interests exist.

The purpose of this study was to evaluate the differences in body composition, neuromuscular performance, and mobility in healthy, regularly exercising and inactive older women, and examine the relationship between skeletal muscle indices and mobility. Overall, 32 healthy older women participated. They were divided into groups according to their physical activity history as regularly exercising (n = 22) and inactive (n = 10) women. Body composition, hand grip strength, leg extensor muscle strength, rapid force development, power output, and mobility indices were assessed. Regularly exercising women had lower fat mass and higher values for leg extensor muscle strength and muscle quality, and also for mobility. Leg extensor muscle strength and power output during vertical jumping and appendicular lean mass per unit of body mass were associated with mobility in healthy older women. It was concluded that long-term regular exercising may have beneficial effects on body composition and physical function in older women.

Objectives: The aim was to examine the changes in metabolic syndrome risk factors over a 2-year period, and to investigate the independent influence of baseline physical activity (PA) and cardiovascular fitness (CVF) on these changes., Methods: 120 Estonian boys (age at baseline 11.9 ± 0.1 years) were grouped according to baseline PA or CVF/kg (VO 2max/kg ) and CVF/ LBM (VO 2max/LBM ). PA was assessed by 7-day accelerometry. Total cholesterol (TC), high-density lipoprotein (HDL), triglycerides (TRG), insulin and glucose were measured and assessment for insulin resistance (HOMA-IR) and TC/HDL ratio were calculated., Results: In both CVF/ kg and CVF/ LBM , the low CVF groups had significantly higher values of HOMA-IR (P < 0.009) over time. In TRG and TC/HDL ratio values the only significant difference over time emerged between CVF/ kg groups (P < 0.001). Participants in high metabolic risk CVF/ kg group were 5.9 times more likely to have high HOMA-IR values, 2.9 times more likely to have high triglyceride values, and 3.5 times more likely to have high TC/HDL ratio values (P ≤ 0.045) in the second year follow-up compared to those who were in the low metabolic risk CVF/ kg group. In moderate-to-vigorous PA groups there were no significant differences between HOMA-IR, TRG, and TC/HDL ratio values over time., Conclusions: The results of the study indicate that CVF has a stronger longitudinal prediction value compared to moderate to vigorous physical activity in terms of metabolic risk factors in adolescent boys. Fitness remained a significant predictor if the influence of body fatness was removed from the analysis. Am. J. Hum. Biol. 28:782-788, 2016. © 2016Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Background: The 2016 Report Card on Physical Activity for Children and Youth, the first of its kind, aims to set baseline physical activity (PA) indicators using the Active Healthy Kids Global Alliance grading system., Methods: A research work group analyzed and selected data for the grade assignment meeting (GAM). During the GAM, 17 leading researchers and policy experts from Estonia assessed the data and assigned grades for each of the 9 PA indicators. In addition, recommendations were provided for further actions to improve the grades., Results: Grades from A (highest) to F (lowest) were assigned as follows: 1) Overall PA (F); 2) Organized Sport (C); 3) Active Play [incomplete data (INC)]; 4) Active Transportation (INC); 5) Sedentary Behaviors (F); 6) Family and Peers (C); 7) School (C); 8) Community and the Built Environment (B); and 9) Government (C). An indicator was marked as incomplete (INC) when there was a lack of representative quality data., Conclusions: Evidence suggests that PA levels of Estonian children remain very low, despite moderately supportive social, environmental, and regulatory factors. There are many challenges to overcome in supporting and promoting PA of children and youth (eg, cross-sectional cooperation, implementing interventions, changing social norms, empowerment of parents and educational institutions).

Background: We investigated longitudinal relationships between the biochemical markers of bone and adipose tissue with bone mineral content (BMC), bone mineral density (BMD), moderate-to-vigorous physical activity (MVPA) and sedentary time (SED) in pubertal boys., Methods: Ninety-six boys (11.9 ± 0.6 years old) were measured at baseline, after 12 and 24 months. Body composition (fat mass [FM], lean body mass [LBM]), and whole body (WB), lumbar spine (LS) and femoral neck (FN) BMD and BMC were assessed. Additionally, serum leptin, adiponectin, osteocalcin (OC) and C-terminal telopeptide of type I collagen (CTX) were measured., Results: OC had a strong longitudinal inverse effect on changes in WB&#95;BMD (p < 0.001) and LS&#95;BMD (p = 0.021), while CTX had an inverse effect only on changes in FN&#95;BMD (p = 0.011). Leptin had an inverse effect on changes in WB&#95;BMC/WB&#95;BMD (p = 0.001), FN&#95;BMD (p = 0.002) and LS&#95;BMD (p = 0.001). MVPA showed a longitudinal inverse effect on changes in leptin (p = 0.030), however no longitudinal effect of SED to biochemical markers of bone and adipose tissue was found., Conclusions: Bone metabolism markers have negative effect on bone mineral accrual during puberty. Increases in MVPA affect leptin, suggesting a positive link of MVPA through leptin metabolism on increases in bone mineralization during puberty.

Background: We aimed to examine the associations of adipocytokines and circulating bone metabolism markers with bone mineral parameters in early pubertal boys with different physical activity level., Methods: Eighty-six early pubertal boys were divided into active and non-active boys according to the accumulated moderate-to-vigorous physical activity (MVPA) level. Body composition and bone mineral parameters were assessed and testosterone, leptin, adiponectin, osteocalcin (OC), and C-terminal telopeptide of type I collagen (CTX) were measured., Results: Active subjects had significantly lower (p<0.05) body mass, body mass index (BMI), fat mass (FM), leptin, and sedentary time values, while non-active subjects had lower (p<0.05) vigorous physical activity level and femoral neck bone mineral density (FN-BMD). OC contributed to the models in physically active group and explained 6.6% and 9.7% of variance in whole body (WB) [F(5,44)=10.847; p<0.001] and lumbar spine bone mineral content (LS-BMC) [F(5,44)=4.158; p=0.004], respectively. No other biochemical parameters were found to be related to bone mineral parameters in either the active or non-active group., Conclusions: Bone metabolism markers were positively correlated with bone mineral values only in active pubertal boys. Leptin and adiponectin were not related to bone mineral parameters in active and non-active pubertal boys.

Physical exercise is known to regulate energy balance. Important to this regulatory system is the existence of several peptides that communicate the status of body energy stores to the brain and are related to the body fatness including leptin, adiponectin and ghrelin. These hormones assist in regulating energy balance as well as somatic and pubertal growth in children. It appears that rather few studies have investigated the responses of leptin, adiponectin and ghrelin to acute exercise and these studies have demonstrated no changes in these peptides as a result of exercise. Leptin levels are decreased and may remain unchanged advancing from prepuberty to pubertal maturation in young male and female athletes. A limited number of studies indicate that adiponectin levels are not different between prepubertal and pubertal athletes and untrained controls. However, in certain circumstances circulating adiponectin could be increased in young athletes after onset of puberty as a result of heavily increased energy expenditure. Ghrelin levels are elevated in young sportsmen. However, pubertal onset decreases ghrelin levels in boys and girls even in the presence of chronically elevated energy expenditure as seen in young athletes. Ghrelin may also be used as an indicator of energy imbalance across the menstrual cycle in adolescent athletes. There are no studies with high-molecular-weight adiponectin and only very few studies with acylated ghrelin responses to acute exercise and chronic training have been performed in young athletes. Since these forms of adiponectin and ghrelin have been thought to be bioactive forms, further studies with these specific forms of adiponectin and ghrelin are needed. In conclusion, further studies should be conducted to investigate the response of these hormones to acute and chronic negative energy balance to better understand their role in regulating energy balance during growth and maturation in young athletes.

The aim of this investigation was to examine the effects of menstrual cycle phase on substrate oxidation and lactate concentration during exercise. Eleven eumenorrheic female rowers (18.4 ± 1.9 years; 172.0 ± 4.0 cm; 67.2 ± 8.4 kg; 27.7 ± 4.8% body fat) completed 1 h rowing ergometer exercise at 70% of maximal oxygen consumption (VO(2max)) during two different phases of the menstrual cycle: the follicular phase (FP) and the luteal phase (LP). Resting and exercise measurements of the whole body energy expenditure, oxygen consumption (VO(2)), respiratory exchange ratio (RER), substrate oxidation and lactate blood levels were made. Energy expenditure, VO(2) and heart rate during the 1-h exercise were not significantly different (P > 0.05) among menstrual cycle phases. Resting RER and RER during the entire 1 h exercise period were not significantly different among menstrual cycle phases. There was an increase (P < 0.05) in RER in the transition between rest and exercise and a further increase in RER occurred after the first 30 min of exercise at both menstrual cycle phases. Blood lactate concentrations significantly increased in the transition between rest and exercise and remained relatively constant during the whole 1 h of exercise in both menstrual cycle phases. No menstrual cycle phase effect (P > 0.05) was observed for blood lactate concentrations. In conclusion, our results demonstrated no effect of menstrual cycle phase on substrate oxidation and blood lactate concentration during rowing exercise at 70% of VO(2max) in athletes. Normally menstruating female rowers should not be concerned about their menstrual cycle phase with regard to substrate oxidation in everyday training.

Unlabelled: Recently, two single nucleotide polymorphisms at position 45 and 276 on the adiponectin gene (ADIPOQ) have been recognized as determinants of total adiponectin levels, insulin resistance, and risk for diabetes in various obese populations., Objectives: The aim of this study was to determine whether these two polymorphisms are indeed determinants in the development of metabolic disorders or whether they are secondary to other confounding factors., Methods: To do so, we have selected 170 physically active adolescent girls (mean age, 14.03 ± 1.5 years and mean body mass index, 19.98 ± 2.5 kg/m²) devoid of any metabolic diseases or confounding factors, to better attribute any findings to genotype effects. Concentration of adiponectin, insulin, and glucose were determined from blood samples with appropriate kits. Body fat parameters were evaluated with dual-energy X-ray absorptiometry, and genotype was analyzed with DNA extracted from whole blood samples followed by polymerase chain reaction and electrophoresis to separate alleles., Results: Neither single nucleotide polymorphism +45T/G nor +276G/T was related to homeostasis model assessment index or adiponectin levels; however, the presence of the G allele on site 45 favored a significant decrease in lean body mass compared with those who were T homozygous (TG:36.90/TT:41.07 kg, P < 0.05)., Conclusions: Results suggest that the reported increase in the risk of diabetes in subjects that were G allele carriers at site 45 in obese populations compared with normal-weight populations can be linked instead to a change in muscle mass or the muscle itself present in this genotype group., (© 2010 Wiley-Liss, Inc.)

The aim of this study was to investigate the possible relationships between adiponectin and leptin with blood lipids (CHOL, HDL-C, LDL-C, and TG) in physically active postmenopausal women. One hundred and thirty-four physically active practicing gymnastics (2-3 times per week) women between the ages of 51 to 85 years participated in this cross-sectional study. Body height, body mass, waist-to-hip circumference ratio (WHR), and BMI were used as anthropometrical parameters. Body composition parameters (fat%, fat mass, fat free mass) were measured by DXA. The fasting adiponectin, leptin, CHOL, HDL-C, LDL-C, and TG were measured. From the anthropometrical and body composition parameters, only WHR correlated significantly with adiponectin (r = -0.306). In addition, adiponectin correlated with TG (r = -0.277) and leptin (r = -0.381). Leptin was positively related to body mass (r = 0.261), and BMI (r = 0.274) from anthropometrical parameters and body fat% (r = 0.288) and fat mass (r = 0.298) from body composition variables. No relationships emerged between leptin and blood lipids. We found that there are some significant relationships between adiponectin, leptin and anthropometrical and body composition parameters in physically active postmenopausal females. From blood lipids, only TG correlated significantly with adiponectin., ((c) 2010 Wiley-Liss, Inc.)

This study is aimed to evaluate whether circulating adiponectin concentration is associated with physical activity (PA) level in healthy older females. To date, daily PA in older adults (> or = 65 years) has primarily relied on self-report. This study used accelerometry, which objectively measured minute-by-minute movement to assess PA volume and intensity performed by elderly females. In addition, body composition, leptin and insulin resistance values were measured to assess the influence of these parameters on the possible relationship between adiponectin and PA levels in this specific age group of older women. On 49 women (mean age: 73.6 +/- 4.2 years), adiponectin, leptin, insulin resistance, body composition and 7-day PA parameters were measured. Average daily accelerometer step counts and time spent in different PA levels were obtained from 7-day PA measurement. Average daily accelerometer step-count was 7,722 +/- 3,069 steps day(-1) and the recommended 150 min weekly of at least moderate/vigorous PA in bouts of at least 10 min was achieved by 71.4% (35/49) of the participants. Correlation analysis showed that plasma adiponectin concentration (16.0 +/- 6.1 microg ml(-1) ) was related (P < 0.001) to steps per day (r = 0.438) and leptin (r = -0.443) values. Multivariate regression analysis further revealed that only steps per day and leptin were independent predictors of circulating adiponectin concentration in healthy elderly females. In conclusion, these data support the hypothesis that being physically active is associated with better adiponectin concentration and a reduced risk of having metabolic disease risk in the specific group of healthy elderly females.

The purpose of this cross-sectional study was to determine the physiological reaction to the different intensity Nordic Walking exercise in young females with different aerobic capacity values. Twenty-eight 19-24-year-old female university students participated in the study. Their peak O2 consumption (VO2 peak kg(-1)) and individual ventilatory threshold (IVT) were measured using a continuous incremental protocol until volitional exhaustion on treadmill. The subjects were analysed as a whole group (n = 28) and were also divided into three groups based on the measured VO2 peak kg(-1) (Difference between groups is 1 SD) as follows: 1. >46 ml min(-1) kg(-1) (n = 8), 2. 41-46 ml min(-1) kg(-1) (n = 12) and 3. <41 ml min(-1) kg(-1) (n = 8). The second test consisted of four times 1 km Nordic Walking with increasing speed on the 200 m indoor track, performed as a continuous study (Step 1 - slow walking, Step 2 - usual speed walking, Step 3 - faster speed walking and Step 4 - maximal speed walking). During the walking test expired gas was sampled breath-by-breath and heart rate (HR) was recorded continuously. Ratings of perceived exertion (RPE) were asked using the Borg RPE scale separately for every 1 km of the walking test. No significant differences emerged between groups in HR of IVT (172.4 +/- 10.3-176.4 +/- 4.9 beats min(-1)) or maximal HR (190.1 +/- 7.3-191.6 +/- 7.8 beats min(-1)) during the treadmill test. During maximal speed walking the speed (7.4 +/- 0.4-7.5 +/- 0.6 km h(-1)) and O2 consumption (30.4 +/- 3.9-34.0 +/- 4.5 ml min(-1) kg(-1)) were relatively similar between groups (P > 0.05). However, during maximal speed walking, the O2 consumption in the second and third groups was similar with the IVT (94.9 +/- 17.5% and 99.4 +/- 15.5%, respectively) but in the first group it was only 75.5 +/- 8.0% from IVT. Mean HR during the maximal speed walking was in the first group 151.6 +/- 12.5 beats min(-1), in the second (169.7 +/- 10.3 beats min(-1)) and the third (173.1 +/- 15.8 beats min(-1)) groups it was comparable with the calculated IVT level. The Borg RPE was very low in every group (11.9 +/- 2.0-14.4 +/- 2.3) and the relationship with VO2and HR was not significant during maximal speed Nordic Walking. In summary, the present study indicated that walking is an acceptable exercise for young females independent of their initial VO2 peak level. However, females with low initial VO2 peak can be recommended to exercise with the subjective 'faster speed walking'. In contrast, females with high initial VO2 peak should exercise with maximal speed.

Purpose: We examined the effect of regular physical activity on plasma ghrelin concentration after onset of puberty in girls. In addition, we also examined the association of fasting plasma ghrelin concentration with various plasma biochemical, body composition, and aerobic capacity variables in healthy adolescent girls., Method: Fifty healthy schoolgirls ages 11 to 16 yr were divided either into a physically active (N = 25) or a physically inactive (N = 25) group. The physically active group consisted of swimmers who had trained on an average of 6.2 +/- 2.0 h.wk(-1) for the last 2 yr, whereas the inclusion criterion for the physically inactive group was the participation in physical education classes only. The subjects were matched for age (+/- 1 yr) and body mass index (BMI; +/- 2 kg.m(-2)). Maturation I group (14 matched pairs) included pubertal stages 2 and 3, and maturation II group (11 matched pairs) included pubertal stages 4 and 5., Results: Physically active girls had significantly higher (P < 0.05) mean plasma ghrelin levels than the physically inactive girls (maturation I: 1152.1 +/- 312.9 vs 877.7 +/- 114.8 pg.mL(-1); maturation II: 1084.0 +/- 252.5 vs 793.4 +/- 164.9 pg.mL(-1)). Plasma ghrelin concentration was negatively related to percent body fat, fat mass, peak oxygen consumption per kilogram of body mass, leptin, estradiol, insulin, and insulin-like growth factor-I (IGF-I) (r > -0.298; P < 0.05). Multivariate linear regression analysis to determine the predictors of ghrelin concentration using the variables that were significantly associated with ghrelin concentration demonstrated that plasma IGF-I was the most important predictor of plasma ghrelin concentration (beta = -0.396; P = 0.008)., Conclusion: Regular physical activity influences plasma ghrelin concentrations in girls with different pubertal maturation levels. Plasma IGF-I concentration seems to be the main determinant of circulating ghrelin in healthy, normal-weight adolescent girls.

The aim of the present investigation was to investigate plasma ghrelin response to acute maximal exercise in elite male rowers. Eight elite male rowers performed a maximal 6000-m rowing ergometer test (mean performance time: 19 mins 52 secs; 1192.1 +/- 16.4 secs), and venous blood samples were obtained before, immediately after, and after 30 mins of recovery. In addition to ghrelin concentration, leptin, insulin, growth hormone, insulin-like growth factor-1 (IGF-1), testosterone, cortisol, and glucose values were measured. Ghrelin was significantly increased immediately after the exercise (+24.4%; P < 0.05) and was not significantly different than baseline after 30 mins of recovery. Leptin was significantly decreased immediately after the exercise (- 15.8%; P < 0.05) and remained significantly decreased after the first 30 mins of recovery. No changes occurred in insulin concentrations. Growth hormone, IGF-1, and testosterone values were significantly increased and decreased to the pre-exercise level immediately after the exercise and after the first 30 mins of recovery, respectively. Cortisol and glucose values were significantly increased immediately after the exercise and remained significantly increased during the first 30 mins of recovery. There were no relationships between plasma ghrelin and other measured blood parameters after the exercise, nor were changes in ghrelin related to changes in other measured blood biochemical values after the exercise. In conclusion, these results suggest that acute negative energy balance induced by specific maximal short-term exercise elicits a metabolic response with opposite changes in ghrelin and leptin concentrations in elite male athletes.

Introduction: Both Estonia and Lithuania have a long history of pediatric fitness testing, but due to a lack of standardized test batteries spanning a substantial number of years, secular changes in fitness test performance have not been previously reported. Using the Eurofit test battery, the aim of this study was to quantify the secular changes in fitness test performance of Estonian and Lithuanian children and adolescents during the first ten years of independence., Methods: Two cross-sectional surveys of Estonian and Lithuanian 11- to 17-year-old tested on the Eurofit in 1992 and 2002 were compared. Secular changes were calculated by first, expressing mean values (at the country x age x sex x test level) in 2002 as a percentage of mean values in 1992, and second, by subtracting 100 from the resultant and then dividing 10 to express the changes as percentage changes per annum (p.a.). Negative values indicated secular declines, and positive values secular improvements., Results: Secular changes in Eurofit test performance were calculated for 12,226 Estonian and Lithuanian children and adolescents over the 10-year period. Across all Eurofit tests, secular changes ranged on average from -0.98 to +0.49% p.a., with performances less variable for Estonian children than for Lithuanian children. Secular changes were strikingly consistent across age and sex groups., Discussion/conclusion: This is the first study to have described the secular changes in Eurofit test performance of children and adolescents from the Baltic states. It shows that between 1992 and 2002, changes in Eurofit performance varied among tests and were not always in line with European and global changes.

The purpose of this study was to investigate the resting and short-duration exercise-induced hormone responses of male rowers as a result of 6 months of volume-extended training season. Body composition, maximal aerobic capacity, and on-water 2000-m sculling performance were assessed before and after a 24-week training in elite rowers (n = 11; 193.1 +/- 5.2 cm; 91.6 +/- 5.8 kg; maximum oxygen consumption [VO2max], 6.2 +/- 0.5 L x min(-1)). Six rowers were selected (SEL; 192.0 +/- 6.3 cm; 93.5 +/- 7.1 kg; VO2max, 6.4 +/- 0.4 L x min(-1)) and 5 were not selected (N-SEL; 194.8 +/- 4.1 cm; 89.6 +/- 4.0 kg; VO2max, 6.0 +/- 0.5 L x min(-1)) for the national team. Resting adiponectin did not change as a result of prolonged training. Adiponectin did not change after 2000-m rowing at baseline either. No responses were also observed 24 weeks later in SEL rowers, whereas a significant decrease (P < .05) was observed in N-SEL rowers. At the same time, leptin also decreased after the first 30 minutes of recovery in N-SEL rowers. After the training period, immediate postexercise increases in growth hormone and testosterone were significantly higher in the whole group of rowers. No differences in cortisol responses were observed before and after the training period in SEL and N-SEL rowers. In conclusion, it appears that resting adiponectin does not change as a result of prolonged training. Training may modify adiponectin response to an short-duration exercise depending on the performance level of athletes. Decreased postexercise adiponectin and leptin values in rowers with lower performance capacity may be indicative of the inadequate recovery of these athletes.

The aim of the study was to test the possible relationships of anthropometrical parameters, somatotype and body composition parameters with bone mineral content (BMC) and bone mineral density (BMD, total body, the dominant arm distal radius, antero-posterior lumbar spine--L2-L4, femoral neck) in strength- (n=33) and endurance- (n=32) trained and sedentary normal-weight (n=41) and overweight (n=23) young females. Their body height and mass were measured and BMI calculated. Nine skinfolds, thirteen girths, eight lengths and eight breadths/lengths were measured. Somatotype components were calculated according to Carter and Heath (1990). Whole body fat percentage, fat mass, lean body mass (LBM), BMC and BMD were measured by DXA. The relationship of different BMC and BMD values at each of the regions studied to the different anthropometrical and body composition parameters were analysed by using a stepwise multiple regression analysis. In all groups, BMC is highly dependent on the body mass (31.5-81.2%, R2x100). In the endurance-trained females, BMD is dependent on LBM, especially in both weight-bearing sites (66.2% in L2-L4 and 35.3% in the femoral neck). LBM explained 77.0% of the total variance of BMC in this group. BMC in the strength-trained group is dependent on the lower body anthropometrical parameters--thigh skinfold (18.2%), calf girth (25.2%), trochanterion length (24.1%) and sitting height (51.4%). From the endurance-trained group, BMC is dependent on hip girth (75.2%) or in combination with ankle girth (81.2%). From the length parameters, trochanterion is the most important (55.8%) and from breadths/lengths, sitting height (57.1%). In the normal-weight females, BMC is dependent on the calf girth (31.1%), trochanterion length (28.2%) and sitting height (29.8%). In the overweight group, only chest girth (20.1%) and biacromial breadth/length (27.0%) had a relationship with BMC. From somatotype components, only ectomorphy explained BMD in the endurance-trained females in the femoral neck (21.3%) and in the lumbar spine (20.9%). We can conclude that from the body composition parameters, LBM is a powerful predictor of BMC and BMD. From the anthropometrical parameters measured, lower body parameters are the most important. Somatotype components (ectomorphy) had a relationship with BMD only in the endurance-trained group. There are some differences that depend on the specific physical activity field. In the endurance-trained group, the anthropometry is more important than in the strength-trained group.

This study examines whether knee extensor muscle isometric, isokinetic, and isoinertial strength values in women with different physical activity and body composition patterns are related to leg bone mineral density (BMD) and bone mineral content (BMC) values. A total of 129 women aged 17-40 participated in this study. They were divided into four groups: strength-trained (n = 33), endurance-trained (n = 32), normal weight sedentary (n = 41), and overweight sedentary (n = 23) women. In addition, the subjects were grouped as physically active (n = 65) or sedentary (n = 64) women. BMD and BMC for both legs (LBMD and LBMC, respectively) and for the dominant leg alone (DLBMC), body fat percentage and lean body mass (LBM), maximal knee extension isometric (ISOM) and isokinetic (ISOK) strength at the angular velocity of 60 deg.s(-1), and isoinertial leg explosive strengths (countermovement jump CMJ) were measured. In endurance-trained women, LBMD was dependent on body mass index (BMI) (33.7% of the variance, R2 x 100), and in the physically active group and the total group with LBM (14.6% and 15.6%, respectively). In the overweight group, LBMD was dependent on ISOK strength (21.7% of the variance, R2 x 100). In the sedentary and total groups, ISOM strength was more important (10.3% and 5.0%, respectively); in the strength-trained group, body weight influenced LBMC, accounting for 71.6% of the variance (R2 x 100). In the endurance-trained women, height influenced LMBC (37.9%, R2 x 100). In sedentary and overweight women, LBM accounted for 52.1% and 61.4% of the total variance in LBMC. In these groups, ISOM strength accounted for 15.3% and 25.9% of the variance in LBMC. In overweight women, ISOM and ISOK strength together influenced LBMC highly (64.8% of the variance, R2 x 100). In the sedentary group, the influence of LBM on LBMC was higher than in the active group (82.1% and 50.5% of the variance, respectively). In the total group, LBM influenced LBMC, accounting for 54.5% of the variance (R2 x 100). ISOM strength (22.7%) alone or in combination with ISOK strength (35.8%) and CMJ (41.7%) (R2 x 100) in LBMC in the sedentary group explained the variance. In the total group, ISOM strength alone (13.2%) or in combination with CMJ (17.1%) influenced LBMC (R2 x 100). Our results suggest that (1) muscle strength and anthropometrical parameters were associated with LBMD; (2) LBM and ISOM strength had a significant relationship with DLBMC and LBMC only in nonathletic women; and (3) strength measured with different regimens highly influenced LBMC compared with LBMD, especially in the sedentary groups.

The purpose of this study was to investigate the potentially important role leptin may play during training monitoring in athletes. Twelve highly trained male rowers underwent a 3-week period of maximally increased training stress followed by a 2-week tapering period. Fasting blood was sampled after a rest day. Subjects also performed a maximal 2000-m rowing ergometer test before and after 3 weeks of heavy training, and after 2 weeks of tapering. Blood samples were obtained before, immediately after and after 30 min of recovery. Leptin concentrations were measured in duplicate by radioimmunoassay. Mean training time was about 100% higher during the heavy training period (17.5 h x week(-1)) compared to the tapering period (8.9 h x week(-1)). The 3-week heavy training period induced a significant reduction ( P<0.05) in the fasting leptin concentration [from 2.5 (0.4) to 1.5 (0.4) ng x ml(-1)]. Fasting plasma leptin was significantly increased by the end of the 2-week tapering period [2.0 (0.4) ng x ml(-1)] but remained significantly lower compared to the pretraining value. Leptin levels were also significantly decreased only after the 2000-m rowing ergometer test performed at the end of the heavy training period. No differences in leptin concentrations were observed after other performance tests compared to their respective baseline values. In addition, fasting leptin concentration was significantly related to the weekly training time ( r=-0.45; P=0.006). In conclusion, it appears that leptin is sensitive to the rapid and pronounced changes in training volume. A greater training time is associated with a lower leptin concentration in highly trained male rowers. It is suggested that it may be possible to direct typical rowing training by monitoring leptin status.

For "The Year That Was 2017," I have selected 3 papers in the area of growth, maturation, and exercise during youth. The first paper has been chosen because it provides for the first time the relative age, maturation, and anthropometric biases on position allocation in elite youth soccer players participating in talent identification programs in professional soccer league. Specific anthropometrical attributes characterized playing positions with a bias toward these athletes who are comparatively tall and heavy for their age already in younger ages, whereas position-specific physical attributes do not become apparent until the later stages of talent development. The second paper was selected because it provides a unique perspective on the contributions of different types of sport activities to the development of soccer performance. This paper demonstrated that early specialization and concentration on one sport only during growth is not beneficial in elite youth soccer. In contrast, variable early sporting experience, and not different physiological parameters, facilitates subsequent soccer performance development. The third paper provided some evidence that the consequence of physical activity during adolescence can be far reaching as physical activity might not only predict academic success during compulsory basic education but also boost educational outcomes in adulthood. [ABSTRACT FROM AUTHOR]

Background: Whole-body vibration training has recently been proposed as a complementary training modality to improve the bone health of adolescent swimmers. However, there is no longitudinal study regarding the effects of this training combination on bone metabolism. Therefore, the main goal was to analyze the effects of swimming and vibration training on bone turnover markers during adolescence. Methods: The present study included 68 adolescent swimmers and 41 normoactive controls (CON). Swimmers were randomly selected to either continue with their regular swimming training (SWI) or participate in an additional vibration protocol (VIB). Anthropometric measurements and serum level determinations of osteocalcin (OC), procollagen type 1 N-terminal propeptide (P1NP) and C-terminal telopeptide crosslaps (CTX) were performed before and after the 6-month intervention. Results: Statistically significant group by time interactions were found for both bone formation markers. VIB showed a decrease over time in OC (baseline: 101.4 μg/mL, follow-up: 82.8 μg/mL, p < 0.05) and P1NP (baseline: 528.4 μg/mL, follow-up: 389.0 μg/mL, p < 0.05) and SWI had analogous reductions in P1NP (baseline: 685.8 μg/mL, follow-up: 542.0 μg/mL, p < 0.05), whereas CON experienced an increase in OC levels (baseline: 94.4 μg/mL, follow-up: 103.4 μg/mL, p < 0.05). After stratifying the sample according to the pubertal status, similar interactions were observed. Conclusions: The combination of swimming training and this particular vibration protocol led to a decrease in bone formation markers, especially during early puberty. Whole-body vibration might not induce an osteogenic stimulus in adolescent swimmers. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate plasma IL-6, TNF-alpha, leptin and ghrelin concentrations during high-volume training. Eight trained male rowers participated. Fasting blood was sampled before (T1) and after (T2) increased training volume and after recovery period (T3). Two-hour rowing was performed at T1, T2 and at T3 with blood samples before, POST and POST 30'. Decrease in fasting leptin was observed at T2 (from 1.31 (0.53) to 0.93 (0.27) ng ml(-1); P < 0.05). Leptin was also significantly decreased at POST and POST 30 exercise compared to PRE test at T2. At T2 POST 30' leptin was significantly lower compared to corresponding value at T1. There were no significant post-exercise changes in ghrelin at T2 compared to T1 and T3. TNF-alpha was significantly increased POST exercise only at T2. In conclusion, high-volume training causes alterations of post exercise leptin and TNF-alpha, while increases in ghrelin are down regulated. [ABSTRACT FROM AUTHOR]

We examined the effect of 6-month volume-extended training on bone metabolism in elite male rowers. Twelve elite male rowers (20.8+/-3.0 years; 192.9+/-4.7 cm; 91.9+/-5.3 kg; body fat 10.1+/-2.3%; VO2max 6.2+/-0.5 l min(-1)) participated in this study. Bone biochemical markers, hormones, bone mineral content (BMC), and bone mineral density (BMD) were assessed before and after training. Average weekly training volume was significantly higher (P<0.05) during the 6 months of heavy training compared to relative rest (11.6+/-0.4 h week(-1) vs. 16.8+/-0.6 h week(-1)), while intensity remained the same. At the end of training, only arm BMD was significantly increased by 5.7%. Osteocalcin (16.6%), insulin-like growth factor-1 (IGF-1) (20.2%) and the bioavailability IGF-1 index (17.9%) were significantly increased. Before heavy training, relationships were observed between the whole body BMD and growth hormone (r=0.64; P< or =0.02), lumbar spine BMD and 1.25(OH)2 vitamin D (r=0.69; P< or =0.04), arm BMD and testosterone (r=0.59; P< or =0.05), and arm BMD and adiponectin (r=0.59; P< or =0.05). No relationship was found between BMC or BMD and blood biochemical measures 6 months later (r=0.56; P> or =0.05). In addition, osteocalcin was related to IGF-1 (r>0.58; P<0.048) and bioavailability IGF-1 index (r>0.59; P< or =0.055) before and after training. In summary, heavy training had a moderately favorable effect on BMD. Bone tissue at specific skeleton sites is sensitive to changes in training volume even in athletes with already high BMD values. Changes in BMD and bone formation may be caused by changes in specific hormones such as IGF-1 and adiponectin in male athletes. [ABSTRACT FROM AUTHOR]

The purpose of present study was to investigate plasma adiponectin response to acute exercise in highly trained male rowers. Ten rowers performed a maximal 6,000-m rowing ergometer test [mean performance time approximately 20 min; 1,200.8 (29.9) s], and venous blood samples were obtained before, immediately after and after 30 min of recovery. In addition to adiponectin concentration, leptin, insulin, growth hormone and glucose values were measured. Adiponectin was not changed immediately after the exercise when uncorrected for plasma volume changes (-8.1%; P>0.05). However, adiponectin was decreased immediately after the exercise when adjusted for plasma volume changes (-11.3%; P<0.05). Adiponectin was significantly increased above the resting value after the first 30 min of recovery (uncorrected for plasma volume, +19.3%; corrected for plasma volume, +20.0%). No changes occurred in plasma leptin and insulin concentrations with exercise (uncorrected for plasma volume changes). While growth hormone and glucose values were significantly increased and decreased to the pre-exercise level immediately after the exercise and after the first 30 min of recovery, respectively (uncorrected for plasma volume changes), no differences in the responses to exercise were observed in these measured blood parameters when adjusting for plasma volume changes. There were no relationships between plasma adiponectin and other measured blood parameters before and after the exercise, nor were changes in adiponectin related to changes in other measured blood biochemical values after the exercise. These results suggest that plasma adiponectin is altered as a result of maximal acute exercise in highly trained athletes. [ABSTRACT FROM AUTHOR]

The aim of our longitudinal study was to investigate the relationships between physical activity and bone mass in boys with different body mass status during the years surrounding pubertal growth spurt. Two hundred and six boys entering puberty took part in this study. The subjects were divided into underweight (), normal weight (), overweight () and obese () groups at baseline according to age related categories. Whole-body DXA scans were performed at baseline, after 12 and 24 months to assess body composition (lean body mass, fat mass), and total body (TB), lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD) parameters. Physical activity was measured by 7- day accelerometry. For longitudinal analysis, multilevel fixed effects regression models were constructed. Biological age, height and lean body mass had an effect for explanation of TB BMD, FN BMD and LS BMD. Moderate to vigorous physical activity (MVPA), vigorous physical activity (VPA) and sedentary time (SED) had the significant effect only on FN BMD. Being an underweight boy at the baseline indicated greater chance (p<0.01) to have lower TB BMD in the future (2 years at follow up) development, compared to normal weight (estimates = −0.038), overweight (estimates = −0.061) and obese boys (estimates = −0.106). [ABSTRACT FROM AUTHOR]

The regulatory effect of ghrelin on growth hormone (GH) is limited in describing ghrelin response to acute submaximal exercise intensities in elite athletes. We investigated the effects of a single sculling exercise performed above and below the individual anaerobic threshold (IAT) on total ghrelin concentration in highly trained male rowers. Nine elite male rowers (20.1 ± 3.7 years; 190.0 ± 5.2 cm; 89.6 ± 4.6 kg; %body fat: 9.9 ± 2.5%) volunteered for this study. Single scull rowing was performed below and above IAT using a mean of 5 bpm above and below the heart rate of the IAT during graded exercise test. Ghrelin, leptin, GH, insulin, and glucose were measured before, immediately after, and after 30 min of recovery. Plasma ghrelin concentration did not increase significantly in either exercise but was approaching significance after 30 min of recovery ( P = 0.051) when the constant load sculling was performed at the intensity above the IAT. There were no changes in plasma leptin levels. GH increased significantly immediately after exercise and remained elevated during the 30 min of recovery in both exercise conditions, while insulin decreased significantly immediately after exercise and remained significantly lower after the 30 min of recovery in both exercise intensities. Baseline ghrelin was not correlated with the body composition, physical performance, or blood biochemical data. There was no significant relationship between plasma ghrelin and other blood variables immediately after the 30 min of recovery in both exercise tests and changes in ghrelin were not related to blood biochemical variables after the exercise tests. The acute constant load sculling exercise above or below IAT that increased GH concentrations did not significantly increase the circulating plasma ghrelin levels. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the effects of arm-crank induced priming on subsequent 20 min Functional Threshold Power Test among 11 well-trained male cyclists (18.8 ± 0.9 years; 182 ± 5 cm; 73.0 ± 6.6 kg; V˙O2max 67.9 ± 5.1 mL·kg−1·min−1). Participants completed an incremental test and two maximal performance tests (MPTs) in a randomized order. Warm-up prior to MPTlow consisted of 20 min aerobic exercise and 25 s high-intensity all-out arm crank effort was added to warm-up in MPThigh. Constant intensities for the first 17 min of MPT were targeting to achieve a similar relative fatigue according to participants' physiological capacity before the last 3 min all-out spurt. Final 3 min all-out spurt power was 4.94 ± 0.27 W·kg−1 and 4.85 ± 0.39 W·kg−1 in MPTlow and MPThigh, respectively (not statistically different: p = 0.116; d = 0.5). Blood lactate [La] levels just before the start were higher (p < 0.001; d = 2.6) in MPThigh (5.6 ± 0.5 mmol·L−1) compared to MPTlow (1.1 ± 0.1 mmol·L−1). According to V˙CO2 and net [La] data, significantly higher anaerobic energy production was detected among MPTlow condition. In conclusion, priming significantly reduced anaerobic energy contribution but did neither improve nor decrease group mean performance although effects were variable. We suggest priming to have beneficial effects based on previous studies; however, the effects are individual and additional studies are needed to distinguish such detailed effects in single athletes. [ABSTRACT FROM AUTHOR]

The article offers information on the Fourth Baltic Conference in Exercise and Sport Sciences to be held in Tartu, Estonia from April 7 to 9, 2011.

The aim of this study was to investigate the effects of three different duration (1, 3 or 5 min) rest intervals on hormonal response in 10x10 hurdle jumping series. Eleven adolescent male sprinters and jumpers (16.2±0.9 years, height 170.5±7.9 cm, body mass 70.9±11.1 kg, body mass index 22.0±3.4 kg/m2) participated in the study. An exercise session consisted of 10 two-legged jumps with arm swing over ten 76 cm high hurdles in 10 series which were separated by either 1-, 3- or 5-minute rest intervals. Venous blood samples were obtained before and after the session and cortisol (CORT), testosterone (TEST) and the growth hormone (GH) concentrations were analyzed. Mean jumping times over 10 hurdles using one (7.67±0.92 sec), three (7.44±0.66 sec) or five (7.14±0.54 sec) minutes of recovery were not significantly different from each other (p>.05). No significant changes were noted in CORT and TEST concentrations as a result of different exercise sessions. Compared with the initial value, GH increased rapidly (p<.001) after the jumping test with a 1-min rest interval. A negative correlation (r=-.791) was found between mean jumping time using 5-min rest intervals and changes in the TEST concentration. This study indicates that short jumping series with different length rest intervals do not significantly change TEST or CORT concentrations. However, the shortest rest interval (one minute) causes significant changes in GH concentration in adolescent sprinters and jumpers. [ABSTRACT FROM AUTHOR]