Physical activity and sedentary time during physical education lessons between different physical activity groups of a sample of Finnish 11-year-old students

Problem statement: Insufficient PA is rising concern in modern society. Physical education as a compulsory subject allows all students to engage physical activity. However, the activity levels may vary during the physical education lesson depending on the motivation of students. Purpose: The purpose of this study was to determine the amount of time spent in light physical activity, moderate to vigorous physical activity and sedentary activity by a sample of Finnish fifth grade students during physical education lessons. Approach: A cohort of 407 Finnish students' (177 boys, 232 girls) participated to study. To determine activity, participants wore GTX3 Actigraphs for seven consecutive days. Participants' activity scores were grouped in quartiles based on their weekly average moderate to vigorous physical activity. Different activity group and gender comparisons were undertaken using MANOVA. Results: Contrasts regarding activity quartiles revealed that in the least active group quartile (Q1) boys had more sedentary time and less MVPA time than in the more active group quartiles (Q3&Q4). Among girls, Q1 girls had less moderate to vigorous physical activity than girls grouped in Q3-Q4, and had more sedentary time than all other quartile groups. Conclusions: Results demonstrated that during PE lessons differences in activity between children with different moderate to vigorous physical activity levels exist. Physical education teachers should consider developing lesson strategies to address the differences identified in ST and MVPA. Programs that foster consistency in student engagement at the moderate to vigorous physical activity level may also support a decrease in levels of sedentary time across the physical education lesson.peerReviewe

Human Sirt-1: Molecular Modeling and Structure-Function Relationships of an Unordered Protein

BACKGROUND: Sirt-1 is a NAD+-dependent nuclear deacetylase of 747 residues that in mammals is involved in various important metabolic pathways, such as glucose metabolism and insulin secretion, and often works on many different metabolic substrates as a multifunctional protein. Sirt-1 down-regulates p53 activity, rising lifespan, and cell survival; it also deacetylases peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and its coactivator 1 alpha (PGC-1alpha), promoting lipid mobilization, positively regulating insulin secretion, and increasing mitochondrial dimension and number. Therefore, it has been implicated in diseases such as diabetes and the metabolic syndrome and, also, in the mechanisms of longevity induced by calorie restriction. Its whole structure is not yet experimentally determined and the structural features of its allosteric site are unknown, and no information is known about the structural changes determined by the binding of its allosteric effectors. METHODOLOGY: In this study, we modelled the whole three-dimensional structure of Sirt-1 and that of its endogenous activator, the nuclear protein AROS. Moreover, we modelled the Sirt-1/AROS complex in order to study the structural basis of its activation and regulation. CONCLUSIONS: Amazingly, the structural data show that Sirt-1 is an unordered protein with a globular core and two large unordered structural regions at both termini, which play an important role in the protein-protein interaction. Moreover, we have found on Sirt-1 a conserved pharmacophore pocket of which we have discussed the implication

Substrates for Efficient Fluorometric Screening Employing the NAD-Dependent Sirtuin 5 Lysine Deacylase (KDAC) Enzyme

The class III lysine deacylases (KDACs), also known as the sirtuins, have emerged as interesting drug targets for therapeutic intervention in a variety of diseases. To gain a deeper understanding of the processes affected by sirtuins, the development of selective small molecule modulators of individual isozymes has been a longstanding goal. Essential for the discovery of novel modulators, however, are good screening protocols and mechanistic insights with regard to the targets in question. We therefore evaluated the activities of the seven human sirtuin hydrolases against a panel of fluorogenic substrates. Both commonly used, commercially available substrates and novel chemotypes designed to address recent developments in the field of lysine post-translational modification were evaluated. Our investigations led to the discovery of two new fluorogenic ε-N-succinyllysine-containing substrates that enable highly efficient and enzyme-economical screening employing sirtuin 5 (SIRT5). Furthermore, optimized protocols for facile kinetic investigations were developed, which should be valuable for enzyme kinetic investigations. Finally, these protocols were applied to a kinetic analysis of the inhibition of SIRT5 by suramin, a potent sirtuin inhibitor previously shown by X-ray crystallography to bind the substrate pocket of the human SIRT5 KDAC enzyme

Longitudinal associations among cardiorespiratory and muscular fitness, motor competence and objectively measured physical activity

Objectives. This study aimed to investigate cross-lagged associations in motor competence, cardiorespiratory fitness, muscular fitness and accelerometer-based moderate-to-vigorous physical activity (MVPA) engagement. Design. One-year prospective follow-up study. Method. A sample was 491 (275 girls;M at baseline = 11.27, SD = .32) Finnish physical education students. Students’ motor competence was assessed by 1) two-legged jumping from side to side test, 2) throwing-catching combination test and 3) 5-leaps test. Their cardiorespiratory fitness was analyzed by a 20-meter shuttle run test and muscular fitness by curl-up and push-up tests. Additionally, students’ MVPA was measured objectively by hip-worn accelerometers. Results. Results demonstrated that: 1) cardiorespiratory fitness measured at Grade 5 was the only significant predictor of later MVPA and this association appeared only in the boys’ group, 2) MVPA assessed at Grade 5 significantly predicted cardiorespiratory fitness in the girls’ group, 3) cardiorespiratory fitness collected at Grade 5 associated with muscular fitness, locomotor and stability skills in both girls and boys, and 4) locomotor skills measured at Grade 5 predicted significantly muscular fitness, locomotor and manipulative skills in both sex groups. Conclusions. Elementary school years are important in providing students with experiences in physical activity (PA) which leads to improvements s in cardiorespiratory health. Additionally, this study showed that cardiorespiratory fitness collected at Grade 5 associated with later muscular fitness, and locomotor and stability skills in both sex groups. These findings are noteworthy because muscular fitness in youth has several health-related benefits and motor competence in childhood and adolescence has positive association with later PA engagement.peerReviewe

Enjoyment and anxiety in Finnish physical education : achievement goals and self-determination perspectives

Approach: The sample of the study included 1148 (565 boys and 583 girls, Mage = 11.27, SD = .32) Grade 5 Finnish PE students who completed a battery of questionnaires including motivational climate, basic psychological needs satisfaction, motivational regulations, goal orientations, perceived competence, enjoyment, and anxiety towards PE. Structural equation modeling was used to investigate two proposed motivational sequences. Purpose: The purpose of this study was to predict students’ enjoyment and anxiety in physical education (PE) through the motivational sequences proposed by self-determination and achievement goal theories. Results: SEM demonstrated a good model fit to the data for the self-determination motivational sequence (χ2 (11) = 13.33, P = 0.27; CFI = 0.99; TLI = 0.99; RMSEA = 0.01). More specifically, the three basic psychological needs and intrinsic motivation were positively linked to enjoyment, whereas amotivation was negatively linked. Furthermore, need for competence and relatedness were negatively linked to anxiety, whereas introjected regulation and amotivation were positively linked to anxiety. Subsequently, the achievement goals model fitted the data well: χ2 (19) = 29.59, P = 0.06; CFI = .99; TLI = 0.99; RMSEA = 0.03. Task-involving climate was positively, and ego-involving climate negatively, associated with enjoyment. Additionally, ego-involving climate was positively linked to anxiety. The SEM also revealed an indirect positive association from task-involving climate via task orientation to enjoyment. Conclusions: Results of this study demonstrate that satisfaction of basic psychological needs and perception of task-involving motivational climate are crucial for positive affect in PE.peerReviewe