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The Abdominal Pressure Twin Sensors (APTS) for Q3 and Q6 dummies are composed of soft polyurethane bladders filled with fluid and equipped with pressure sensors. Implanted within the abdominal insert of child dummies, they can be used to detect abdominal loading due to the belt during frontal collisions. In the present study - which is part of the EC funded CASPER project - two versions of APTS (V1 and V2) were evaluated in abdominal belt compression tests, torso flexion test (V1 only) and two series of sled tests with degraded restraint conditions. The results suggest that the two versions have similar responses, and that the pressure sensitivity to torso flexion is limited. The APTS ability to detect abdominal loading in sled tests was also confirmed, with peak pressures typically below 1 bar when the belt loaded only the pelvis and the thorax (appropriate restraint) and values above that level when the abdomen was loaded directly (inappropriate restraint). Then, accident reconstructions performed as part of CASPER and previous EC funded projects were reanalyzed. Selected data from 19 dummies (12 Q6 and 7 Q3) were used to plot injury risk curves. Maximum pressure, maximum pressure rate and their product were all found to be injury predictors. Maximum pressure levels for a 50% risk of AIS3+ were consistent with the levels separating appropriate and inappropriate restraint in the sled tests (e.g. 50% risk of AIS3+ at 1.09 bar for pressure filtered CFC180). Further work is needed to refine the scaling techniques between ages and confirm the risk curves.

Background The purpose of this study is to quantify the in vivo mechanical response of the child trunk under loading during physiotherapy treatments. Methods Twenty-six children aged 45 days to 7 years (14 girls and 12 boys) took part in this study. The forces applied by the physiotherapist were recorded using a force-plate embedded in the manipulation table supporting the child. Two synchronized cameras filmed the scene in a calibrated environment. The displacement of reflective targets glued on the physiotherapist's hands was calculated using an automatic tracking procedure and the 3D reconstruction “Direct Linear Transformation” algorithm. The progression of physical parameters was evaluated according to the age of the child. They included force, displacement, normalized displacement, loading speed, displacement and normalized displacement at the maximum force, force at the maximum displacement, viscous criterion and effective stiffness. Findings For all patients, the mean maximum displacement and load were 22 mm (SD 9 mm) and 240 N (SD 46 N) respectively. The force–displacement curves had shown the complexity of the in vivo behavior: four phases have been distinguished with cycles in respect with the respiratory phases. The increase in force always occurred before the increase in displacement. Interpretation This study helps to understand the in vivo behavior of the child trunk subjected to repetitive non-injurious mechanical loading. Further analysis in other populations and with different therapeutic maneuvers would refine the results.

34e Congrès de la Société de Biomécanique, TOULON, FRANCE, 31-/08/2009 - 02/09/2009; The aim of our study is to obtain realistic values of child thoracic and abdominal compliance. The thoracic and abdominal compliance represents the capacity of deformation under spontaneous or mechanical ventilation. The Pediatric Medical Center (CMP) in la MaisonneŽe receives children with neuromuscular pathologies ventilated with invasive or non-invasive methods. The respiratory function of these children naturally deteriorates over time, and breathing development programs, that may or may not be associated with thoracic pressure, are put in place to minimise this mostly restrictive aggravation. Intermittent positive pressure breathing (IPPB) is a technique used to provide short-term or intermittent mechanical ventilation for the purpose of augmenting lung expansion, delivering aerosol medication, or assisting ventilation. The 'traditional' use of IPPB lacks precise evaluation, especially of thoracic mobility. Poster : hal-01738729

22nd Congress of the International Society of Biomechanics, CAPE TOWN, AFRIQUE DU SUD, 05-/07/2009 - 09/07/2009; The aim of this study was to determine the loading level of child trunk during physiotherapy treatments

The 5th World Congress of Biomechanics, MUNICH, ALLEMAGNE, 29-/07/2006 - 04/08/2006