Is physical fitness associated with the type of attended school? A cross-sectional analysis among adolescents.

BACKGROUND: While academic achievement has been associated with physical activity, the present work questions the potential association between the physical fitness level of adolescents and the type of school they attend, ranging from academic to technical schools. METHODS: The Diagnoform© Test was performed by 20,228 young French students from 76 schools (9196 females), mean age 15.8±1.8 years. This dataset includes two higher education institutions (N.=870), 37 general high schools (N.=13,125), 18 professional-oriented high schools (N.=3569), 5 agricultural high schools (N.=132), 2 vocational training centers (N.=202) and 12 rural vocational training centers (N.=1137). RESULTS: In higher education institutions and general high schools, girls showed better performances for all physical tests. A decreasing Quotient of overall Physical fitness Condition (QPC) was observed for both genders from urban higher education schools to rural and technical institutions (P<0.001). The proportion of total variance accounting for within institution variation is strong (intra-class correlation coefficients [ICC] 0.20 [0.15; 0.27] for QPC). CONCLUSIONS: The lower physical fitness level observed here among students from technical or training schools places them at higher risks for the development of future chronic diseases. These results suggest that specific interventions are needed depending on the educational setting.

Energy Intake Evaluation by a Learning Approach Using the Number of Food Portions and Body Weight.

An accurate quantification of energy intake is critical; however, under-reporting is frequent. The aim of this study was to develop an indirect statistical method of the total energy intake estimation based on gender, weight, and the number of portions. The energy intake prediction was developed and evaluated for validity using energy expenditure. Subjects with various BMIs were recruited and assigned either in the training or the test group. The mean energy provided by a portion was evaluated by linear regression models from the training group. The absolute values of the error between the energy intake estimation and the energy expenditure measurement were calculated for each subject, by subgroup and for the whole group. The performance of the models was determined using the test dataset. As the number of portions is the only variable used in the model, the error was 26.5%. After adding body weight in the model, the error decreased to 8.8% and 10.8% for the normal-weight women and men, respectively, and 11.7% and 12.8% for the overweight women and men, respectively. The results prove that a statistical approach and knowledge of the usual number of portions and body weight is effective and sufficient to obtain a precise evaluation of energy intake after a simple and brief enquiry.

The eMouveRecherche application competes with research devices to evaluate energy expenditure, physical activity and still time in free-living conditions.

The proliferation of smartphones is creating new opportunities to monitor and interact with human subjects in free-living conditions since smartphones are familiar to large segments of the population and facilitate data collection, transmission and analysis. From accelerometry data collected by smartphones, the present work aims to estimate time spent in different activity categories and the energy expenditure in free-living conditions. Our research encompasses the definition of an energy-saving function (PredEE) considering four physical categories of activities (still, light, moderate and vigorous), their duration and metabolic cost (MET). To create an efficient discrimination function, the method consists of classifying accelerometry-transformed signals into categories and of associating each category with corresponding Metabolic Equivalent Tasks. The performance of the PredEE function was compared with two previously published functions (f(η,d)aedes,f(η,d)nrjsi), and with two dedicated sensors (Armband® and Actiheart®) in free-living conditions over a 12-h monitoring period using 30 volunteers. Compared to the two previous functions, PredEE was the only one able to provide estimations of time spent in each activity category. In relative value, all the activity categories were evaluated similarly to those given by Armband®. Compared to Actiheart®, the function underestimated still activities by 10.1% and overestimated light- and moderate-intensity activities by 7.9% and 4.2%, respectively. The total energy expenditure error produced by PredEE compared to Armband® was lower than those given by the two previous functions (5.7% vs. 14.1% and 17.0%). PredEE provides the user with an accurate physical activity feedback which should help self-monitoring in free-living conditions.

A smartphone-driven methodology for estimating physical activities and energy expenditure in free living conditions.

This paper introduces a function dedicated to the estimation of total energy expenditure (TEE) of daily activities based on data from accelerometers integrated into smartphones. The use of mass-market sensors such as accelerometers offers a promising solution for the general public due to the growing smartphone market over the last decade. The TEE estimation function quality was evaluated using data from intensive numerical experiments based, first, on 12 volunteers equipped with a smartphone and two research sensors (Armband and Actiheart) in controlled conditions (CC) and, then, on 30 other volunteers in free-living conditions (FLC). The TEE given by these two sensors in both conditions and estimated from the metabolic equivalent tasks (MET) in CC served as references during the creation and evaluation of the function. The TEE mean gap in absolute value between the function and the three references was 7.0%, 16.4% and 2.7% in CC, and 17.0% and 23.7% according to Armband and Actiheart, respectively, in FLC. This is the first step in the definition of a new feedback mechanism that promotes self-management and daily-efficiency evaluation of physical activity as part of an information system dedicated to the prevention of chronic diseases.

Interstitial thermal ablation with a fast rotating dual-mode transducer.

Interstitial ultrasound applicators can be a minimally invasive alternative for treating targets that are unresectable or are inaccessible by extracorporeal methods. Dual-mode transducers for ultrasound imaging and therapy were developed to address the constraints of a miniaturized applicator and real-time treatment monitoring. We propose an original treatment strategy that combines ultrasound imaging and therapy using a dual-mode transducer rotating at 8 revolutions per second. Real-time B-mode imaging was interrupted to emit high-intensity ultrasound over a selected therapy aperture. A full 360 degrees image was taken every 8th rotation to image the therapy aperture. Numerical simulations were performed to study the effect of rotation on tissue heating, and to study the effect of the treatment sequence on transducer temperature. With the time-averaged transducer surface intensity held at 12 W/cm(2) to maintain transducer temperature below 66 degrees C, higher field intensities and deeper lesions were produced by narrower therapy apertures. A prototype system was built and tested using in vitro samples of porcine liver. Lesions up to 8 mm were produced using a time-averaged transducer surface intensity of 12 W/cm(2) applied for a period of 240 s over a therapy aperture of 40 degrees. Apparent strain imaging of the therapy aperture improved the contrast between treated and spared tissues, which could not be differentiated on B-mode images. With appropriate limits on the transducer output, real-time imaging and deep thermal ablation are feasible and sustainable using a rotating dual-mode transducer.

In vivo evaluation of a mechanically oscillating dual-mode applicator for ultrasound imaging and thermal ablation.

Unresectable liver tumors are often treated with interstitial probes that modify tissue temperature, and efficacious treatment relies on image guidance for tissue targeting and assessment. Here, we report the in vivo evaluation of an interstitial applicator with a mechanically oscillating five-element dual-mode transducer. After thoroughly characterizing the transducer, tissue response to high-intensity ultrasound was numerically calculated to select parameters for experimentation in vivo. Using perfused porcine liver, B-mode sector images were formed before and after a 120-s therapy period, and M-mode imaging monitored the therapy axis during therapy. The time-averaged transducer surface intensity was 21 or 27 W/cm (2). Electroacoustic conversion efficiency was maximally 72 +/- 3% and impulse response length was 295 +/- 1.0 ns at -6 dB. The depth of thermal damage measured by gross histology ranged from 10 to 25 mm for 13 insertion sites. For six sites, M-mode data exhibited a reduction in gray-scale intensity that was interpreted as the temporal variation of coagulation necrosis. Contrast ratio analysis indicated that the gray-scale intensity dropped by 7.8 +/- 3.3 dB, and estimated the final lesion depth to an accuracy of 2.3 +/- 2.4 mm. This paper verified that the applicator could induce coagulation necrosis in perfused liver and demonstrated the feasibility of real-time monitoring.

Dual-mode ultrasound transducer for image-guided interstitial thermal therapy.

Deep-seated tumors can be treated by minimally invasive interstitial ultrasound thermal therapy. A miniature transducer emitting high-intensity acoustic waves is placed in contact with the targeted area to induce local thermal necrosis. Accurate positioning of the probe and treatment monitoring must be achieved for the technique to be effective. A piezocomposite technology was used for obtaining both high-quality imaging and effective treatment with the same transducer. Prototypes were designed and built to be compatible with an endoscopic approach for treating cholangiocarcinomas in the biliary ducts. The transducer had dimensions of 2.5 x 7.5 mm(2), it was cylindrically focused at 10 mm and it was operated at a center frequency of 11 MHz. Transducer efficiency was measured at 71%, and the impulse response corresponded to an axial resolution of 0.2 mm. In-vitro tests were conducted on samples of pig liver in which lesions up to 10 mm in depth were induced. B-mode images were obtained by mechanically rotating the transducer. Treatments were monitored in three ways: (i) classical M-mode images, (ii) images of local deformation of ultrasound lines during heating and (iii) comparison of the displacements induced in the tissue by radiation force, before and after treatments. The successful use of piezocomposite materials to manufacture dual-mode transducers opens new perspectives for interstitial ultrasound thermal therapy.