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Alain Boussuges1, Olivier Gavarry21French Armed Forces Biomedical Research Institute, Brétigny sur Orge and UMR MD2, Aix-Marseilles University, Marseilles, France; 2Engineering Laboratory for Handicaps. South University of Toulon – Var, La Garde, FranceWe have read with interest the study published in the International Journal of General Medicine entitled “Hypotensive response after water-walking and land walking exercise sessions in healthy trained and untrained women” by Rodriguez et al.1 In this study, the authors investigated cardiovascular changes induced by walking in water in comparison with walking on land. Water exercises are commonly used in rehabilitation programs, particularly patients with mobility problems. Recently, some studies have suggested that exercise performed in water could improve cardiovascular function.2View original paper by Bocalini et al.

Aim. – This paper reviews the effect of gender and life conditions on physical activity during growth.Topics. – Physical activity is reduced during puberty and decreases from 60 min/day at 10 years to 20 min/day at 20 years. During teenage, girls are the less active and their participation to intense activity (>6 Mets) is lower. Socio-economical conditions, marginal malnutrition, cold and hot climates, altitude and ethnic origins have no major influences on the quantity of daily physical activity (average daily heart rate close to 100 bpm). The need of physical activity is similar during growth whatever ethnic origins and live conditions. However these factors may influence the type of habitual physical activities. The time devoted to video activities (on average 1 à 3 h/day) is negatively correlated to physical activity score.Futures prospects. – A main objective in the next 10 years is to deal with the interactions between biological, psychological and sociological factors affecting physical activity.Conclusion. – Physical activity depends mainly on age and sex. [Copyright &y& Elsevier]

Background: In contrast with Advanced Footwear Technology-AFT running shoes for long-distance, little is known about AFT sprint spikes on performance and acceleration parameters. However, their use has become widespread since the Tokyo 2020 Olympics, and knowledge of their effects would seem to be an essential starting point before any clinical or socio-economic considerations., Objectives: Our objectives were to determine intra- and inter-subject sprinting performance modifications with Nike ® AFT spikes (NAS) compared to standard spiked-shoes (SS)., Methods: Healthy regional to national sprint athletes (n = 21, ≥ 750 pts World Athletics) performed 16 repetitions of 30-m sprints with either the NAS or SS condition during a single session, based on the multiple N-of-1 method, with pairwise randomisation and double-blind procedure. Time on 30-m sprints (Stalker radar), force-velocity profile (F 0 , V 0 , V max , P max , RF, D RF and FVP slope), and confounding factors (wind and shoe mass) were measured. Statistical analyses included a mixed linear regression model for group analyses, and randomisation test inversion and non-overlap-of-all-pair (NAP) methods for intra-individual analysis., Results: NAS improved 30-m time by a mean of - 0.02 s (SMD = 0.4, p = 0.014), with no interaction with any confounding factors. Significant changes were seen in velocity (V max : SMD = 0.9, p < 0.001; V 0 : SMD = 0.7, p < 0.001) and the horizontal ratio of force (RF max : SMD = 0.5, p = 0.043), with no changes observed in force production. Whatever the footwear, one unit of positive wind (+ 1 m.s - 1 ) improved performance by - 0.03 s (p < 0.001). At an individual level, four athletes improved (NAP ≥ 0.69), and one had a statistical decrease in performance. Changes in F-V profiles were largely individual., Conclusions: A positive effect on sprint acceleration characteristics was observed when using Nike ® AFT spikes, due to an increase in velocity and the horizontal ratio of force. A major variability in inter-individual response justifies single-case experimental designs for research on the topic., Trial Registration Number: NCT05881148., (© 2024. The Author(s).)

Background: A sedentary lifestyle is commonly associated with a higher risk of chronic disease development. Among school-aged children from European countries, screen-time represents a significant portion of sedentary time with 39.8% of children spending more than 2h/day in front of a screen on average. Therefore, effective solutions to reduce sedentary behavior (SB) must be found. Multilevel interventions based on the socio-ecological model (SEM) are particularly relevant to take into account influences of the social environment on individuals' SB. Moreover, the trans-contextual model (TCM) can offer complementary levers for individuals' behavior change. The CIPRES study is a theory-based multilevel intervention designed to decrease the SB in French primary school children aged 8-10 years. The present paper describes the protocol of a randomized controlled study to evaluate the effectiveness of the CIPRES multilevel intervention on SB., Methods: The CIPRES study is a cluster-randomized controlled trial comparing intervention vs control groups. A total of 700 children are targeted for inclusion, distributed in four municipalities considered as clusters. The study consists of two successive phases: 1) co-building of a SB prevention intervention by using a participatory approach involving representatives of each level of the SEM (e.g., children, parents, staff from municipalities, teachers) and 2) implementation and evaluation of the intervention. The intervention will last for 6 weeks in each involved class. Primary outcome will be the sedentary time of children per week, assessed by accelerometry. In addition, children and their parents will be asked to fill out questionnaires concerning children's physical activity level, screen time, quality-of-life and variables of the TCM., Discussion: This study will give information on the effectiveness of a theory-based intervention, involving multiple levels of actors in the co-construction and the implementation of the intervention, that may interest schools and public health officers looking for innovative sedentary prevention programs., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Carayol et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: To compare the effects of dance and aerobic exercise on cognition and neuropsychiatric symptoms in older people with cognitive impairment., Methods: Twenty-three older adults (mean age = 78 ± 7 years; males: n = 7, females: n = 16) attending a day care center and diagnosed with cognitive impairment were randomly assigned to a 16-week dance intervention or an aerobic exercise intervention (60 min/week). Cognitive function [Mini-Mental State Examination (MMSE)], neuropsychiatric symptoms [Geriatric Depression Scale-15 (GDS-15), Neuro-Psychiatric Inventory-R (NPI-R)], and physical function [Timed Up and Go (TUG), Activity Daily Living (ADL)] were assessed at baseline and at the end of the intervention. After Borg scale assessment, these two physical activities were performed at similar intensity (60-70% HRR)., Results: MMSE score increased significantly after the intervention in the dance group (+ 3.3/+ 14%, p = 0.03), especially memory performance (+1/+220%, p = 0.03), but not in the aerobic exercise group. GDS-15 and NPI-R decreased significantly after the intervention in both groups (p < 0.001). However, no significant effect was found for TUG and ADL., Conclusion: Dance is a cost-effective multimodal intervention that could improve cognition. A low-frequency ecological dance intervention (once per week; 60 min) could improve cognition, especially verbal memory. These results should be further investigated for the practice of dance in facilities for older adults., (© 2023. The Author(s), under exclusive licence to European Geriatric Medicine Society.)

Purpose: To investigate which type, frequency, duration, intensity, and volume of chronic exercise might more strongly reduce pro-inflammatory cytokines and enhance anti-inflammatory cytokines in human and animal models with Mild Cognitive Impairment (MCI) or dementia., Design: A systematic review., Data Source: English-language search of 13 electronic databases: Web of Science, PubMed/Medline, Sport Discus, Scopus, Cochrane, Psych Net, Springer, ScienceDirect, Pascal & Francis, Sage journals, Pedro, Google Scholar, and Sage., Inclusion Criteria: (i) human and animal studies that included exercise, physical activity, or fitness training as an experimental intervention, (ii) studies that addressed MCI, dementia, or AD, (iii) studies that focused on measuring cytokines and/or other inflammatory and/or neuroinflammatory immune markers, (iii) studies that examined inflammatory indicators in blood, CSF (Cerebrospinal Fluid), and brain tissue., Results: Of the 1290 human and animal studies found, 38 were included for qualitative analysis, 11 human articles, 25 animal articles, and two articles addressing both human and animal protocols. In the animal model, physical exercise decreased pro-inflammatory markers in 70.8 % of the articles and anti-inflammatory cytokines: IL -4, IL -10, IL-4β, IL -10β, and TGF-β in 26 % of articles. Treadmill running, resistance exercise, and swimming exercise reduce pro-inflammatory cytokines and increase anti-inflammatory cytokines. In the human model, 53.9 % of items reduced pro-inflammatory proteins and 23 % increased anti-inflammatory proteins. Cycling exercise, multimodal, and resistance training effectively decreased pro-inflammatory cytokines., Conclusion: In rodent animal models with AD phenotype, treadmill, swimming, and resistance training remain good interventions that can delay various mechanisms of dementia progression. In the human model, aerobic, multimodal, and resistance training are beneficial in both MCI and AD. Multimodal training of moderate to high intensity multimodal exercise is effective for MCI. Voluntary cycling training, moderate- or high-intensity aerobic exercise is effective in mild AD patients., Competing Interests: Declaration of competing interest The authors declare no competing interests. No grant is required., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Concerns regarding marked differences in the weights and body composition of young rugby players competing within the same age groups have led to the suggestion of alternative models for grouping young players. The aims of this study were (1) to compare variance in the body size and body composition of schoolboy rugby players (9 to 14 years), across weight- and age-grading models, and (2) to identify morphotypes for the weight model using Hattori's body composition chart., Materials and Methods: Skinfold thickness measurements were used to assess body fat mass (BF), fat-free mass (FFM), body fat mass index (BFMI), and fat-free mass index (FFMI). Standardized measure of height and weight were taken for all participants. Data were grouped according to the age categories of the French Rugby Federation (U11: Under 11 years, U13: Under 13 years, and U15: Under 15 years), and to the weight categories (W30-44.9; W45-59.9; and W60-79.9) carried out from 25th and 75th weight percentile in each age category. Body mass index status (NW normal-weight versus OW/OB overweight/obese) was considered. Extreme morphotypes are characterized from BFMI and FFMI in the weight-grading model on Hattori's body composition chart., Results: The dispersion of anthropometric characteristics decreased significantly for the weight model, except for height in all groups and BFMI for U13. Among NW, 3, 1.8, and 0% upgraded; 18.2, 68.7, and 45.5% downgraded; among OW, 50, 21.5, and 12.5%; and among OB, 91.3, 83.3, and 74.6% upgraded, respectively, in U11, U13, U15. FFMI/BFMI were correlated in U11 ( r = 0.80, p < 0.001), U13 ( r = 0.66, p < 0.001), and U15 ( r = 0.77, p < 0.001). There was no significant correlation in W45-59.9 and low correlations in W30-44.9 ( r = 0.25, p < 0.001) and W60-79.9 ( r = 0.29, p < 0.001). Significant grading difference between the centroids ( p < 0.05) and the distribution deviates from centroids of BFMI and FFMI ( p < 0.0001) were noted between the two models. Thirteen players were located in adipo-slender, twenty-three in adipo-solid, twenty-two in lean-slender, and two located in the lean-solid morphotype in weight model., Conclusion: A weight-grading model should be considered to limit mismatches in anthropometric variables. However, variations of body composition also persisted for this model. Hattori's body composition chart allowed more detailed examination of morphological atypicalities among schoolboy rugby players., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Lentin, Cumming, Piscione, Pezery, Bouchouicha, Gadea, Raymond, Duché and Gavarry.)

Introduction: Adenosine is an ATP derivative that is strongly implicated in the cardiovascular adaptive response to exercise. In this study, we hypothesized that during exercise the hyperemia, commonly observed during exercise in air, was counteracted by the downregulation of the adenosinergic pathway during hyperoxic exposure., Methods: Ten healthy volunteers performed two randomized sessions including gas exposure (Medical air or Oxygen) at rest and during exercise performed at 40% of maximal intensity, according to the individual fitness of the volunteers. Investigations included the measurement of adenosine plasma level (APL) and the recording of hemodynamic data [i.e., cardiac output (CO) and systemic vascular resistances (SVR) using pulsed Doppler and echocardiography]., Results: Hyperoxia significantly decreased APL (from 0.58 ± 0.06 to 0.21 ± 0.05 μmol L -1 , p < 0.001) heart rate and CO and increased SVR in healthy volunteers at rest. During exercise, an increase in APL was recorded in the two sessions when compared with measurements at rest (+0.4 ± 0.4 vs. +0.3 ± 0.2 μmol L -1 for medical air and oxygen exposures, respectively). APL was lower during the exercise performed under hyperoxia when compared with medical air exposure (0.5 ± 0.06 vs. 1.03 ± 0.2 μmol L -1 , respectively p < 0.001). This result could contribute to the hemodynamic differences between the two conditions, such as the increase in SVR and the decrease in both heart rate and CO when exercises were performed during oxygen exposure as compared to medical air., Conclusion: Hyperoxia decreased APLs in healthy volunteers at rest but did not eliminate the increase in APL and the decrease in SVR during low intensity exercise., (Copyright © 2020 Boussuges, Rives, Marlinge, Chaumet, Vallée, Guieu and Gavarry.)

Background: Water immersion has demonstrated its effectiveness in the recovery process after exercise. This study presents for the first time the impact of water immersion on heart rate recovery after low-intensity cycle exercise., Methods: Sixteen male volunteers were involved in the study. The experiment consisted of two cycling exercises: 1 h in ambient air and 1 h in water (temperature: 32 ± 0·2°C). The exercise intensity was individually prescribed to elicit around 35%-40% of VO 2 peak for both conditions. Heart rate recovery was analysed according to recognized methods, such as the differences between heart rate at exercise completion and within the 2 min recovery period., Results: Although the two exercises were performed both at same energy expenditure and heart rate, the indexes used to assess the fast and slow decay of the heart rate recovery were significantly shortened after exercise in water., Conclusion: The results of the present study suggest that cycling in thermoneutral water decreases the cardiac work after exercise when compared with cycling on land., (© 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.)

Background: In some sports such as rugby, a large body size is an advantage, and the desire to gain weight can bring young players to become overweight or obese. The aim of this study was to evaluate the prevalence of overweight and obesity and the contribution of body fat mass index (BFMI) and fat-free mass index (FFMI) to body mass index (BMI) changes among young male rugby players (15-a-side rugby)., Methods: The criteria of the International Obesity Task Force were used to define overweight and obesity from BMI. The method of skinfold thickness was used to assess percentage of body fat (%BF), BFMI, and FFMI. Excess body fat was defined by using BFMI and %BF above the 75th percentile. Data were grouped according to the age categories of the French Rugby Federation (U11, under 11 years; U13, under 13 years; U15, under 15 years) and to BMI status (NW normal-weight versus OW/OB overweight/obese)., Results: Overall, 32.8% of the young players were overweight, and 13.8% were obese. However, 53% of young players classified as obese and overweight by BMI had an excess body fat by using BFMI above the 75th percentile. FFMI increased significantly between U11 and U13 in both groups, without significant change in BMI and BFMI. Both groups had similar significant gains in BMI and FFMI between U13 and U15, while BFMI only increased significantly in OW/OB (+ 18.5%). The strong correlations between BMI and %BF were systematically lower than those between BMI and BFMI. FFMI was strongly or moderately associated with BFMI., Conclusions: Chart analysis of BFMI and FFMI could be used to distinguish changes in body composition across age categories in young male rugby players classified as normal-weight, overweight, and obese by BMI.

Head-up tilt test is useful for exploring neurally mediated syncope. Adenosine is an ATP derivative implicated in cardiovascular disturbances that occur during head-up tilt test. The aim of the present study was to investigate the impact of hyperoxia on adenosine plasma level and on hemodynamic changes induced by head-up tilt testing.Seventeen healthy male volunteers (mean age 35 ± 11 years) were included in the study. The experiment consisted of 2 head-up tilt tests, 1 session with subjects breathing, through a mask, medical air (FiO2 = 21%) and 1 session with administration of pure oxygen (FiO2 = 100%) in double-blind manner. Investigations included continuous monitoring of hemodynamic data and measurement of plasma adenosine levels.No presyncope or syncope was found in 15 of the 17 volunteers. In these subjects, a slight decrease in systolic blood pressure was recorded during orthostatic stress performed under medical air exposure. In contrast, hyperoxia led to increased systolic blood pressure during orthostatic stress when compared with medical air. Furthermore, mean adenosine plasma levels decreased during hyperoxic exposure before (0.31 ± 0.08 μM) and during head-up tilt test (0.33 ± 0.09 μM) when compared with baseline (0.6 ± 0.1 μM). Adenosine plasma level was unchanged during medical air exposure at rest (0.6 ± 0.1 μM), and slightly decreased during orthostatic stress. In 2 volunteers, the head-up tilt test induced a loss of consciousness when breathing air. In these subjects, adenosine plasma level increased during orthostatic stress. In contrast, during hyperoxic exposure, the head-up tilt test did not induce presyncope or syncope. In these 2 volunteers, biological study demonstrated a decrease in adenosine plasma level at both baseline and during orthostatic stress for hyperoxic exposure compared with medical air.These results suggest that hyperoxia was able to increase blood pressure during head-up tilt test via a decrease in plasma adenosine concentration. Our results also suggest that adenosine receptor antagonists are worth trying in neurocardiogenic syncope.

The aim of this study was to compare the cardiorespiratory alterations induced by a low-intensity exercise performed on land or in water. Sixteen healthy subjects were investigated. The exercise consisted of a 1-h period of ergocycling at 35%-40% of peak oxygen uptake. Investigations were performed at rest and 45 min after the beginning of the exercises. Hemodynamic changes were studied by Doppler-echocardiography. Gas exchanges were continuously monitored by an oxygen gas analyzer. Blood samples were taken successively at baseline, within the last minutes of the exercise bout, and during recovery to measure total protein concentration and natriuretic peptides. Cardiovascular parameters were not significantly different during exercise performed on land or in water. As a result of an accelerated breathing frequency, ventilation output was significantly greater in water. Biological changes included a decrease in total protein concentration and an increase in natriuretic peptides in water. During low-intensity exercise, ventilatory alterations favoured increasing the work of breathing while in the water when compared with the same exercise performed on land. Hemodynamic changes were similar in the 2 conditions. Furthermore, biological findings suggest that the fluid transfer from intravascular sector toward interstitial sector could be facilitated in water.

The purpose of this study was to determine the substrate oxidation rate and the exercise intensity at which maximal lipid oxidation and ventilatory threshold (VT) occur in obese (BMI: 36.6 ± 6.3 kg · m(-2)) and normal-weight adolescent girls (BMI: 18.7 ± 1.6 kg · m(-2)) aged 14-18 years. Substrate oxidation rate was determined by gas exchange using an incremental field test involving walking. Body composition was assessed by bioelectrical impedance. Carbohydrate oxidation rates were significantly higher in obese than in normal-weight girls at speeds ranging from 4 to 6 km · h(-1) (P < 0.05), whereas no significant differences were observed between groups regarding lipid oxidation rates. The crossover point of substrate utilisation and the VT were significantly lower in obese than in normal-weight adolescents (P < 0.05). Maximal lipid oxidation rate was observed at 46 ± 15 and 53 ± 15 %EVO2max in obese and normal-weight adolescents, respectively. At these intensities, the Lipox(max) was significantly lower in obese than in normal-weight girls (6.7 ± 2.3 versus 8.9 ± 3.5 mg · min(-1) · kg(-1) FFM, P < 0.05, 95% CI: -3.7 to -0.7, d = -0.74). The present results have implications in designing interventions to promote lipid oxidation and energy expenditure during walking in severely obese adolescent girls.

Objective: The glossopharyngeal insufflation maneuver (lung packing) is largely performed by competitive breath-hold divers to improve their performance, despite observational evidence of fainting and loss of consciousness in the first seconds of apnea., Methods: We describe here the time course of hemodynamic changes, induced by breath-holding with and without lung packing, in 2 world-class apnea competitors., Results: When compared with apnea performed after a deep breath (100% vital capacity), lung packing leads to a decrease in cardiac output, blood pressure, and cerebral blood flow during the first seconds after the beginning of apnea. The major hemodynamic disorders were observed in diver 1, who exhibited the greater increase in pulmonary volume after lung packing (+22% for diver 1 vs +10% for diver 2). After the initial drop in both cardiac output and blood pressure, the time course of hemodynamic alterations became quite similar between the two apneas., Conclusions: Some recommendations, such as limiting the number of maneuvers and performing lung packing in the supine position, should be expressed to avoid injuries secondary to the use of glossopharyngeal insufflation., (Copyright © 2014 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.)

Immersion in thermoneutral water increases cardiac output and peripheral blood flow and reduces systemic vascular resistance. This study examined the effects of head-out water immersion on vascular function. Twelve healthy middle-aged males were immersed during 60 min in the seated position, with water at the level of xiphoid. Local and central vascular tone regulating systems were studied during that time. Brachial artery diameter and blood flow were recorded using ultrasonography and Doppler. Endothelial function was assessed with flow-mediated dilation. Results were compared with the same investigations performed under reference conditions in ambient air. During water immersion, brachial artery diameter increased (3.7 ± 0.2 mm in ambient air vs. 4 ± 0.2 mm in water immersion; p < 0.05). Endothelium-mediated dilation was significantly lower in water immersion than in ambient air (10% vs. 15%; p = 0.01). Nevertheless, the difference disappeared when the percentage vasodilatation of the brachial artery was normalized to the shear stimulus. Smooth muscle-mediated dilation was similar in the 2 conditions. Spectral analysis of systolic blood pressure variability indicated a decrease in sympathetic vascular activity. Plasma levels of nitric oxide metabolites remained unchanged, whereas levels of natriuretic peptides were significantly elevated. An increase in brachial blood flow, a decrease in sympathetic activity, a warming of the skin, and an increase in natriuretic peptides might be involved in the increase in reference diameter observed during water immersion. Endothelial cell reactivity and smooth muscle function did not appear to be altered.

In this pilot study, we wished to determine whether a 5-month multidisciplinary programme of a combined dietary-nutritional education-exercise intervention would have favourable effects on the health status of 18 obese adolescent girls. Before and after the clinical intervention, body composition and habitual physical activity were assessed by bioelectrical impedance and accelerometry, respectively. Aerobic fitness and substrate utilization were determined by gas exchange using an incremental field test that mimics habitual conditions. Despite a significantly (P < 0.001) greater loss of fat mass (-8.7 +/- 4.1 kg) compared with fat-free mass (-2.8 +/- 2.2 kg), energy expenditure at rest decreased by 9% following the intervention. Maximal oxygen consumption [Vdot]O2max related to fat-free mass increased by 7% (P < 0.05), whereas substrate utilization during exercise did not change following the intervention. Moderate and intense physical activity increased by 15% (+20 min . day(-1); P < 0.05) and 45% (+25 min . day(-1); P < 0.01), respectively. A significant relationship was observed between change in habitual physical activity and change in .[Vdot]O2max fat-free mass (r = 0.56, P = 0.01). The present multidisciplinary programme enhanced the loss of fat mass relative to fat-free mass but not sufficiently so to prevent a decline in metabolic rate during rest. Our results suggest a coupling in the improvement of aerobic fitness and habitual physical activity in obese adolescent girls, and hence an improvement in behaviour in relation to physical activity.

Background: Acute hyperoxic exposure is known to modify cardiovascular parameters like a decrease in cardiac output, arterial vasoconstriction, and autonomic nervous system changes. We hypothesized that repeated hyperbaric hyperoxic exposures, as experienced by military oxygen divers, lead to long-term arterial alterations., Methods: Arterial blood pressure measurements and pulse wave velocity (PWV) recordings were performed during basal conditions in 15 elite military oxygen divers, and compared to 15 non-diver controls. The two groups were matched appropriately for physical characteristics (age: 35 +/- 5 yr, weight: 77 +/- 8 kg, height: 177 +/- 6 cm, body mass index: 24.6 +/- 2.0 kg x m(-2)), and aerobic capacity (VO2max : 52 +/- 7 ml x min(-1) x kg(-1))., Results: No significant difference was found in systolic blood pressure (120 +/- 11 mmHg), diastolic blood pressure (70 +/- 8 mmHg), or pulse pressure (50 +/- 7 mmHg). Furthermore, there was no significant difference in the carotid-femoral PWV (6.7 +/- 0.9 m x s(-1)), the carotid-radial PWV (8.7 +/- 1.7 m x s(-1)), or the carotid-pedal PWV (8.1 +/- 1.1 m x s(-1)) between divers and controls., Conclusion: No difference in arterial compliance was observed in physically well-trained military oxygen divers in comparison with matched controls.

Background: Because patients with Crohn's disease (CD) often show increased energy expenditure, nutritional deficiencies, and general fatigue, all which may persist after a flare, we hypothesized that CD could alter muscle mass and function. This study aimed to assess muscle strength and endurance in CD patients in clinical remission and the influencing factors., Methods: Forty-one outpatients (17 men and 24 women; age, 37 +/- 10 yr), in remission (CD Activity Index < 150) for > 3 months, and 25 age-matched healthy controls (10 men and 15 women; age, 37 +/- 13 yr) were evaluated. Evaluation included a sit-up test, hand-grip strength test, hand-grip endurance test, lower limb strength test, and lower limb endurance test (LE), as well as a measure of physical activity., Results: No significant difference was found between CD and control groups regarding weight, height, body mass index, fat mass, and fat-free mass. Strength performance was lower in CD subjects compared with controls, particularly for lower limb indexes: lower limb strength test (-24.6%, P < 0.001), LE (-25.8%, P < 0.001), and sit-up test (-25.1%, P < 0.001). Previous disease severity, disease duration, the cumulative dose of glucocorticosteroids, current inflammation, and global habitual physical activity did not affect muscle performance. A recent use of steroids improved LE., Conclusions: CD patients in clinical remission have decreased muscle function that may affect their quality of life. This pattern is reflected by reduced strength and endurance indexes, particularly for lower limbs. The reasons for these changes need further study. Strength training should be assessed in these patients.

The three objectives of the present review of the literature were to: characterize the evolution of habitual physical activity (HPA) during growth; evaluate the tracking of HPA from childhood to adulthood; and analyse the level of HPA in children and adolescents according to public health recommendations. Data indicates that HPA decreases from childhood to adulthood about 7% per year, with a great reduction during puberty and adolescence concurrent to changes in the type of physical activity. It appears that HPA is not quite steady (0.09 < r < 0.66) during growth, which means that behavioural changes occur. Being very active during childhood or adolescence does not necessarily translate into a high level of HPA in adulthood. The mean values of HPA of children and adolescents vary from 15 to 90 min.day(-1) between studies, and for most of them HPA has been higher or close to public health recommendations. However, these results mask a great number of children and adolescents who are inactive or becoming inactive (40 to 45% of the population).

We hypothesized that the repetition of brief epochs of hypoxemia in elite human breath-hold divers could induce an adaptation of their metabolic responses, resulting in reduced blood acidosis and oxidative stress. Trained divers who had a 7-10 year experience in breath-hold diving, and were able to sustain apnea up to 440 sec at rest, were compared to control individuals who sustained apnea for 145 sec at the most. The subjects sustained apnea at rest (static apnea), and then, performed two 1-min dynamic forearm exercises whether they breathed (control exercise) or sustained apnea (dynamic apnea). We measured arterial blood gases, venous blood pH, and venous blood concentrations of lactic acid, thiobarbituric acid reactive substances (TBARS), and two endogenous anti-oxidants (reduced glutathione, GSH, and reduced ascorbic acid, RAA). In control subjects, the three experimental conditions elicited an increase in blood lactic acid concentration and an oxidative stress (increased TBARS, decreased GSH and RAA concentrations). In divers, the changes in lactic acid, TBARS, RAA, and GSH concentrations were markedly reduced after static and dynamic apnea, as well as after control exercise. Thus, human subjects involved in a long duration training programme of breath-hold diving have reduced post-apnea as well as post-exercise blood acidosis and oxidative stress, mimicking the responses of diving animals.

The influence of morphological, biological, sociological, psychological, and environmental factors on the practice of organized sports and the amount of moderate to vigorous physical activity was examined through a questionnaire and continuous heart-rate monitoring, for 80 schoolchildren, 11 to 16 years old. Sport-practicing boys had a lower percentage of fat mass. Sport-practicing girls had more frequently sport-practicing mothers and higher scores on achievement motivation than nonsport-practicing girls. Active boys had more frequently sport-practicing fathers than inactive boys. No statistically significant correlation was found between moderate to vigorous physical activity and organized sports. Those children who are the most involved in organized sports are thus not necessarily the most active ones.

The links between morphological, biological, sociological, psychological, and environmental characteristics, the practice of organized sports, and moderate to vigorous physical activities were examined by means of a questionnaire given to 48 high-school students aged between 16 and 19 years and their continuous heart-rate monitoring. Few correlations appear between these characteristics and moderate to vigorous physical activities. Only maximal oxygen uptake is linked to this type of activity in girls. Concerning sport involvement, correlations were more numerous for girls than boys. Physical and sports activities of girls were linked with maximal oxygen uptake, sport involvement of father, support, and encouragements of practice, perception of own activity, and private environment. Among boys, physical and sport activities were only linked with sport involvement of friends and perception of own activity. Unlike boys, physical and sport activities among girls seemed more strongly linked to sociological characteristics than other ones.

Diurnal variations in ventilatory and cardiorespiratory responses to submaximal treadmill exercise were analysed in 11 eumenorrhoeic women and in 10 women using monophasic oral contraceptives. Subjects performed submaximal treadmill exercise at three intensities averaging 7, 8, and 9 km x h(-1), each for 4 min at 0800, 1300 and 1700 hours, assigned randomly on 3 separate days. Rectal temperature was measured before (T(rec(b))) and after (T(rec(a))) exercise. Cardiac frequency (f(c)), ventilation (V(E)), oxygen uptake (VO(2)), carbon dioxide output (VCO(2)), and respiratory exchange ratio (R) were assessed in the last minute of each stage of the exercise. Both T(rec(b)) and T(rec(a)) increased from 0800 to 1700 hours (P < 0.001). For a given submaximal work rate, VO(2) and VCO(2) were higher in the afternoon compared to the morning. Similarly, R was increased at 1700 hours compared to 0800 hours during the recovery period following exercise (P < 0.05). However, V(E) did not vary significantly during the day at any of the running intensities. No significant interactions (group x time of day) were observed in any of the studied parameters. In contrast to ventilation, the VO(2) and VCO(2) of the females during submaximal exercise were both affected by the time of day, without any differences between eumenorrhoeic women and users of oral contraceptives.

Time of day variations in maximal anaerobic leg exercise were studied in 23 men mean age 23 (SD 3) years. All the subjects performed two anaerobic tests (force-velocity and multi-jump tests) and those familiar with sprinting ran an additional 50-m dash (n = 16). The maximal anaerobic powers for cycling and jumping (Pcycling and Pjump) and maximal anaerobic velocity (vpeak) were performed consecutively in the same order for all tests. The force-velocity and force-power relationships were established to determine Pcycling. The flight time (tf) and the ground contact time (tc) were recorded from five consecutive jumps on a jump-ergometer to calculate Pjump. The vpeak was measured between the 35th and the 45th m during the dash-run. The test schedules were at 0900, 1400 and 1800 hours on separate days in random order. Rectal temperatures (Tre) and body mass (mb) were measured before each test. The Tre increased significantly from 0900 to 1800 hours (P < 0.001) but mb did not vary during the day (P > 0.05). The Pcycling and Pjump were higher at 1400 and 1800 hours than at 0900 hours. The differences between the morning and the afternoon reached 3% (P < 0.05) for Pcycling and 5%-7% for Pjump (P < 0.01). The time-of-day effect was significant for tf (P < 0.05) but not for tc. During the dash-run tests, the differences almost reached significance for vpeak between 0900 and 1800 hours (P = 0.0544). No significant variations were observed between 1400 and 1800 hours for cycling, jumping and running tests. A time-of-day effect in the maximal anaerobic power of cycle and multi-jump tests existed. Such variations would have pronounced effects when expressed in competitions.

Heart rate (HR) was monitored in 66 French pubertal boys (B, n = 28) and girls (G, n = 38) aged 11-16 years to evaluate habitual physical activity (HPA) over a 1-week period in the winter. The HR and the percentage of heart rate reserve (%HRR) were taken to be indexes of the metabolic activity for the whole day and for the different parts of the day. The HPA was evaluated from the time spent each day below 50%HRR, between 50%-70%HRR and above 70%HRR, which related to the time spent in no or low physical activity (NLPA), moderate physical activity (MPA) and vigorous physical activity (VPA), respectively. No sex differences were observed in the average %HRR each day [%HRRmean, [B 30 (SD 4)%; G 32 (SD 4)%]] or in NLPA [B 715 (SD 61) min, G 711 (SD 81) min] and VPA [B 19 (SD 16) min, G 21 (SD 21) min] throughout the week. During school days, daily %HRRmean was 7% smaller in 14-16 year olds compared to 11-13 year olds. This was linked to a decrease in MPA and a concomitant increase in NLPA (P < 0.05). Daily %HRRmean varied significantly during the week (range: 28-34% HRR). There were significant differences among the periods of the day (P < 0.05). The HR was the greatest during physical education lessons [128 (SD 11) beats x min(-1)], recreation [113 (SD 15) beats x min(-1)] and lunch break [108 (SD 12) beats x min(-1)] and the lowest during the evening [94 (SD 10) beats x min(-1)]. It was only during the lunch breaks that %HRRmean was greater (P < 0.05) on school days than on free days. Of all the teenagers studied 32% were considered active during the week.