Is there any relationship between physical activity level and patterns, and physical performance in children?

<p>Abstract</p> <p>Background</p> <p>It is often assumed that physical activity (PA) and physical performance during childhood and adolescence are beneficial for health during adulthood, but a positive relationship between PA and physical performance has not been precisely clarified in children. The lack or the weakness of the relationships between PA and physical performance could be due to the measure of PA. If the use of accelerometry is considered as an objective and common measure of PA, the real patterns of children's habitual PA must be reflected. The aim of this study was to investigate the relationship between the levels and patterns of PA assessed with high frequency accelerometry and physical performance in young children.</p> <p>Methods</p> <p>Eighty-six boys and 101 girls aged 6-12 years participated in this study. Physical activity was measured over a 7-day period, using a 5-s epoch. Physical performance was assessed by means of EUROFIT tests (anthropometrics, standing broad jump, the 10 × 5 meter shuttle run, the sit-and-reach, the handgrip, the number of sit-ups in 30 seconds, the 20-meter shuttle run).</p> <p>Results</p> <p>No relationship was found between PA and physical performance. In boys only, body fatness was negatively associated with vigorous PA (r = -0.38, p < 0.001) and very high PA (r = -0.35, p < 0.01), in contrast to light PA (r = 0.28, p < 0.01), which was positively related to body fatness.</p> <p>Conclusion</p> <p>In 6- to- 12 year- old children, the more active children were not the fittest. Our results also underline the need for uniformity in approach to measurement of PA, body composition and health-related fitness between studies.</p

Injury risk factors, screening tests and preventative strategies: A systematic review of the evidence that underpins the perceptions and practices of 44 football (soccer) teams from various premier leagues

Purpose: To systematically review the scientific level of evidence for the ‘Top 3’ risk factors, screening tests and preventative exercises identified by a previously published survey of 44 premier league football (soccer) teams. Also, to provide an overall scientific level of evidence and graded recommendation based on the current research literature. Methods: A systematic literature search (Pubmed [MEDLINE], SportDiscus, PEDRO and Cochrane databases). The quality of the articles was assessed and a level of evidence (1++ to 4) was assigned. Level 1++ corresponded to the highest level of evidence available and 4, the lowest. A graded recommendation (A: strong, B: moderate, C: weak, D: insufficient evidence to assign a specific recommendation) for use in the practical setting was given. Results: Fourteen studies were analysed. The overall level of evidence for the risk factors previous injury, fatigue and muscle imbalance were 2++, 4 and ‘inconclusive’, respectively. The graded recommendation for functional movement screen, psychological questionnaire and isokinetic muscle testing were all ‘D’. Hamstring eccentric had a weak graded ‘C’ recommendation, and eccentric exercise for other body parts was ‘D’. Balance/proprioception exercise to reduce ankle and knee sprain injury was assigned a graded recommendation ‘D’. Conclusions: The majority of perceptions and practices of premier league teams have a low level of evidence and low graded recommendation. This does not imply that these perceptions and practices are not important or not valid, as it may simply be that they are yet to be sufficiently validated or refuted by research

Objectively assessed recess physical activity in girls and boys from high and low socioeconomic backgrounds

BackgroundThe school environment influences children&rsquo;s opportunities for physical activity participation. The aim of the present study was to assess objectively measured school recess physical activity in children from high and low socioeconomic backgrounds.MethodsFour hundred and seven children (6&ndash;11 years old) from 4 primary schools located in high socioeconomic status (high-SES) and low socioeconomic status (low-SES) areas participated in the study. Children&rsquo;s physical activity was measured using accelerometry during morning and afternoon recess during a 4-day school week. The percentage of time spent in light, moderate, vigorous, very high and in moderate- to very high-intensity physical activity were calculated using age-dependent cut-points. Sedentary time was defined as 100 counts per minute.ResultsBoys were significantly (p&thinsp;&lt;&thinsp;0.001) more active than girls. No difference in sedentary time between socioeconomic backgrounds was observed. The low-SES group spent significantly more time in light (p&thinsp;&lt;&thinsp;0.001) and very high (p&thinsp;&lt;&thinsp;0.05) intensity physical activity compared to the high-SES group. High-SES boys and girls spent significantly more time in moderate (p&thinsp;&lt;&thinsp;0.001 and p&thinsp;&lt;&thinsp;0.05, respectively) and vigorous (p&thinsp;&lt;&thinsp;0.001) physical activity than low-SES boys.ConclusionsDifferences were observed in recess physical activity levels according to socioeconomic background and sex. These results indicate that recess interventions should target children in low-SES schools.<br /

Exercices intermittents brefs à hautes intensités (influence de la modalité de récupération sur le temps limite d'exercice et le temps passé à haut pourcentage en VO2max)

Ce travail s'articule autour de 4 études qui ont pour but de proposer une méthode de détermination du temps passé à un haut niveau de VO2 adaptée aux exercices intermittents (étude 1) ; de comparer les effets du type de récupération (active versus passive) lors d'exercices intermittents brefs (15 s) et intenses sur les temps passés à un haut niveau de VO2 (étude 2), sur le temps limite (étude 3), et sur l'oxygénation musculaire (étude 4). Dans la première étude, nous avons proposé une méthode originale de détermination du temps passé à VO2max. Les résultats des 2e, 3e et 4e études montrent que, lors des exercices intermittents de 15 s, les temps limites sont plus longs lorsque les périodes de récupération sont passives. Lorsque les exercices intermittents, entrecoupés de récupérations actives ou passives, sont menés jusqu'à épuisement, les temps passés à un haut pourcentage de VO2max ne sont pas significativement différents.The purpose of the studies included in the present thesis was to propose a standardised procedure to determine the time spent at VO2max based on the VO2max of the day (study 1); to compare the effects of recovery type (active vs passive) for high intensity intermittent exercise (15-s) on the time spent at a high percentage of VO2max (study 2), the time to exhaustion (study 3), the muscle oxygenation (study 4). In the first study, an original method was proposed to determine the time spent at VO2max. Results of 2nd, 3rd, and 4th studies have shown that, for high intensity intermittent exercise interspersed with 15-s of passive or active recovery, the times to exhaustion were longer when recovery periods were passive. The time spent at a high percentage of VO2max was not significantly different between the two types of intermittent exercise.LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Fondo e velocita massimale aerobica

Conseils aux enseignants d'éducation physique qui veulent évaluer l'endurance de leurs élèves. Utilisation dans ce contexte du concept de la vitesse maximale aérobie (VMA), applications lors des tests de terrain

Time spent at a high percentage of VO2max for short intermittent runs : active versus passive recovery

International audienceThe purpose of this study was to compare the effects of recovery type (active vs. passive) on the time spent at VO(2)max and above 90 % of VO(2)max during short intermittent runs (15 s) at 120 % of maximal aerobic speed. Twelve male subjects performed a graded test and intermittent runs (15 s) alternated with 15 s of active recovery (50 % of maximal aerobic speed) or with 15 s of passive recovery to exhaustion. The time to exhaustion during the intermittent runs with active recovery (445 +/- 79 s) was significantly shorter (p < 0.001) compared with passive recovery (745 +/- 171 s). No significant difference was found between time spent at VO(2)max and above 90 % of VO(2)max for intermittent runs alternated with active recovery (180 +/- 121 s and 282 +/- 117 s, respectively ) and intermittent runs alternated with passive recovery (191 +/- 135 s and 317 +/- 132 s, respectively ). The times spent at VO(2)max (p < 0.05) and above 90 % of VO(2)max (p < 0.001), expressed in percentage of time to exhaustion, were significantly longer for intermittent runs alternated with active recovery (41 +/- 27 % and 64 +/- 24 %, respectively) than with passive recovery (25 +/- 16 % and 43 +/- 16%, respectively). In conclusion, the present study has shown that the time to exhaustion during repeated high-intensity exercise was significantly greater for passive compared with active recovery, despite no difference in absolute time spent at a high percentage of VO(2)max. However, the time spent at a high percentage of VO(2)max, expressed as a percentage of time to exhaustion, was significantly higher for active compared with passive recovery

Modélisation de la relation temps limite de course versus intensité relative de l'exercice (applications à l'entraînement)

La modélisation de la relation entre le temps limite d'exercice et la vitesse de déplacement (tlim=f(V)) lors de la course à pied permet de calculer les paramètres vitesse critique (VC) et capacité de distance anaérobie (CDA). Ce travail a trois objectifs principaux 1) expliquer en partie la variabilité importante des temps limites de course lorsque l'intensité de l'exercice est déterminée en pourcentage de la consommation maximale d'oxygène (VO2max), 2) analyser l'influence du modèle mathématique, utilisé pour le calcul de la relation tlim=f(V), 3) étudier les effets d'un entraînement intermittent à allures supramaximales sur les paramètres VC et CDA, en relation avec les modifications de la vitesse au seuil d'inadaptation ventilatoire (Vseuil) et du déficit maximal accumulé en oxygène. Les résultats de la première étude montrent qu'en tenant compte de la VC et de la vitesse maximale de course, il est possible de proposer des intensités d'exercices individualisées permettant de réduire la variabilité des temps limites de course. La seconde étude confirme l'influence du choix du modèle mathématique sur la détermination des paramètres VC et CDA. L'utilisation d'un modèle hyperbolique à trois composantes permet de calculer une VC non significativement différente de la Vseuil. Dans la troisième étude, la VC et de la CDA sont significativement augmentés après entraînement, mais l'amplitude des modifications est dépendante du modèle mathématique utilisé. Des relations significatives sont obtenues entre les variations de la VC calculée à l'aide du modèle linéaire et les variations du VO2max. Le modèle linéaire semble le plus intéressant dans une perspective de terrain. Il permet une estimation de la Vseuil et est sensible aux effets de l'entraînement. Son utilisation est très accessible, ce qui est d'un intérêt particulier pour les entraîneurs et les enseignants d'éducation physique.Time versus velocity relationship for running exercises : applications to training. Calculation of the relationships between time limit (tlim) and velocity (tlim=f(V)) allows the determination of the critical velocity (Cv) and anaerobic distance capacity (ADC). The aims of this thesis were 1) to explain the variability of time limit when exercise intensity is expressed as a percentage of maximal oxygen uptake (VO2max), 2) to analyse the influence of the equation used to fit the tlim=f(V) relationship on the Cv and ADC parameters, 3) to determine the effects of a high intensity training program on the Cv and ADC parameters, with regard to changes in ventilatory threshold (Vtresh) and maximal accumulated oxygen deficit. The first study demonstrated that exercise intensity individualized according to Cv and maximal velocity allowed to reduce the interindividual tlim variability. The second study confirms the influence of the mathematical model on the Cv and ADC parameters determination. The Cv calculated with the 3 component hyperbolic model was not significantly different from Vtresh. In the last study, the training program allowed a significant improvement of Cv and ADC. However, the magnitude of the improvement depends on the mathematical model used. Significant relationships were found between changes in Cv (linear model) and changes in VO2max. In an in-the-field perspective, the linear model seems to be the most interesting for coaches or physical education teachers.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Fondo e velocita massimale aerobica

Conseils aux enseignants d'éducation physique qui veulent évaluer l'endurance de leurs élèves. Utilisation dans ce contexte du concept de la vitesse maximale aérobie (VMA), applications lors des tests de terrain

Performances lors d'un exercice intermittent anaérobie: comparaison entre enfants et sujets matures

International audienceDesign.The purpose of the study was to compare the ability of children and mature subjects to repeat 20 s anaerobic exercises.Methods.Twelve children (11.6 ± 1.0 years old) and 12 mature subjects (18.4 ± 2.4 years old) performed a maximal aerobic test and an intermittent anaerobic test. For the latter, they had to repeat 6 all-out 20 s runs with 1 min passive recovery between repetitions. For both tests, blood lactate concentration was measured from capillary samples taken after 2 and 20 min recovery. Heart rate was continuously recorded.Results.For the intermittent anaerobic test, the decrease in performance between the first and sixth runs was greater in mature subjects than in children (15% vs 7%, P < 0.001). Post-exercise lactate ions concentration was higher in mature subjects than in children (17.2 ± 3.6 vs 12.0 ± 1.7 mmol.l−1 P < 0,001). However, lactate decrease rates (%·min−1) calculated between the second and twentieth minutes of recovery were similar in children and in mature subjects. Finally, during recovery between repetitions, the heart rate decrease was significantly faster in children than in mature subjects.Discussion and conclusion.As compared with mature subjects, children have a greater ability to repeat anaerobic exercises. This may be explained by a lower anaerobic contribution, or a higher aerobic contribution during exercises and by faster recovery.Objectifs.Comparer l'aptitude d'enfants et de sujets matures à répéter des exercices de 20 secondes sollicitant la filiére anaérobie.Méthodes.Douze enfants (11,6 ±1,0 ans) et 12 sujets matures (18,4 ± 2,4 ans) réalisent un test maximal aérobie et un test intermittent anaérobie. Lots de ce second test, les sujets ont à parcourir six fois la plus grande distance possible en 20 secondes. Les répétitions sont entrecoupées d'une minute de récupération passive. Lors des deux tests, des prélèvements sanguins capillaires sont effectués aux 2e et 20e minutes de récupération afin de mesurer les concentrations en ions lactate. La fréquence cardiaque est enregistrée en continu.Résultats.Lors du test intermittent anaérobie, la diminution de performance entre la 1re et la 6e répétition est moins importante chez les enfants que chez les sujets matures (7 % contre 15 %, p < 0,001). Les sujets matures sont caractérisés par des concentrations en ions lactate post-exercice supérieures à celles des enfants (17,2 ±3,6 contre 12, 0 ± 1,7 mmol.l−1, p < 0,001). En revanche, les taux de récupération du lactate (%·min−1) calculés entre les 2e et 2e minutes de récupération sont comparables chez l'enfant et le sujet mature. Enfin, lots de la récupération entre les répétitions, la diminution de fréquence cardiaque est plus rapide chez l'enfant que chez le sujet mature.Discussion et conclusion.Les résultats de cette étude indiquent que l'enfant arrive à répéter des exercices anaérobies à une plus haute intensité relative que le sujet mature. Cette différence peut s'expliquer par une sollicitation moindre de la filiére anaérobie lactique lors de l'exercice intermittent, ou par une contribution plus importante des processus oxydatifs, et par des possibilités de récupération plus rapides chez l'enfant

Time spent at VO2max: a methodological issue

Contains fulltext : 157769.pdf (publisher's version ) (Open Access)RU Radboud Universiteit, 24 juni 2016Promotores : Cillessen, A.H.N., Bukowski, W.M. Co-promotores : Haselager, G.J.T., Lansu, T.A.M.176 p