Isokinetic trunk flexors and extensors performance with and without gravity correction.

We study the influence of the calculation of the trunk gravity correction, in standing position, on the isokinetic trunk flexors and extensors performance of a healthy population. Thirty men and 30 women are subjected to two tests, one with gravity correction, the other without, at angular speeds of 30 degrees/s and 120 degrees/s. In all cases the results with gravity correction show: a significant decrease of Peak Torque (PT) and Power (P) recorded on the trunk flexors and a significant increase of Peak Torque and Power recorded on the trunk extensors. Thus, the flexors/extensors ratios (50%) of both parameters are quite different from the ratios usually referred to in the literature (70%).

[Multidimensional analysis of reactive forces of the foot during normal walking]. / Analyse multidimensionnelle des forces de réaction du pied au cours de la marche normale.

The authors present the analysis of the three components of ground reaction forces on both left and right feet on 50 subjects. Fourier analysis shows that a 25-Hz sampling is sufficient to fully characterize the normal gait. The approach used in order to study the data tables built for each component consisted in principal component factor analysis. This multivariate method, which looses the least possible information in relation to raw data, has indicated a high variability between subjects. Concerning the intrasubject variability, great asymmetry occurred between the forward and back forces. With respect to the relationship, the three components, the medial-lateral force was very independent of the two others. Particular classes of normal gait have been proposed.

Diazotype materials for laser recording.

Diazotype materials are sensitive to light in the blue and ultraviolet region. Their photosensitivities are many orders of magnitude lower than silver halide materials. For these reasons, diazotype materials are used mainly as duplicating materials, not for source recordings. In this paper, two methods for improving the photosensitivity of diazotype materials are described. In one method, a small amount of scattering centers are dispersed in the polymer binder of the film to increase the efficiency of the absorbed actinic light in the photodecomposition of the diazonium compound. In another method, the azo dye and vesicular processes are combined in the same film to create a high-density recorded image. The applications of these improved diazotype films to the laser imaging systems and digital data storage are discussed.