The present paper is to study the center line of the plantar pressure of normal young people, and to find the relation between center line of the plantar pressure and gait stability and balance. The paper gives the testing principle and calculating methods for geometric center of plantar pressure distribution and the center of pressure due to the techniques of footprint frame. The calculating formulas in both x direction and y direction are also deduced in the paper. In the experiments carried out in our laboratory, the gait parameters of 131 young subjects walking as usual speed were acquired, and 14 young subjects of the total were specially analyzed. We then provided reference data for the walking gait database of young people, including time parameters, space parameters and plantar pressure parameters. We also obtained the line of geometry center and pressure center under the foot. We found that the differences existed in normal people's geometric center line and the pressure center line. The center of pressure trajectory revealed foot movement stability. The length and lateral changes of the center line of the plantar pressure could be applied to analysis of the plantar pressure of all kinds of people. The results in this paper are useful in clinical foot disease diagnosis and evaluation of surgical effect.
Foot ; physiology ; Gait ; Humans ; Pressure ; Reference Values ; Walking

Objective To evaluate the effect of isosceles right angle triangulation on deep vein puncture under ultrasound localization. Methods In this prospective randomized case-controlled clinical study, the enrolled patients who required deep veins puncture to establish transient hemodialysis pathway were randomly divided into treatment group treated with ultrasound localization puncture based on isosceles right triangle theory, and control group treated with traditional localization puncture following exploration of blood vessels using color doppler ultrasound, with 46 cases in each group. The differences in gender, age, causes for hemodialysis, puncture sites, successful rate of initial puncture, rates of complications and cathetering-consuming time were compared between two groups. Results The differences in gender, age, causes for hemodialysis and puncture sites between two groups were not statistically significant. In control group, 30 patients received puncture through internal jugular veins, among whom 16 received successful initial puncture, with the successful rate of initial puncture of 53.33%, and the cathetering-consuming time of (545.5 ± 120.3) s; and 16 patients received puncture through femoral veins, among whom 8 received successful initial puncture, with the successful rate of initial puncture of 50.00%, and the cathetering-consuming time of (500.6 ± 120.6) s. Meanwhile, in control group, 3 patients had hematoma in puncture sites, and another 3 had arterial mis-puncture, with the total rate of complications of 13.04%(6/46). In treatment group, 32 patients received puncture through internal jugular veins, among whom 31 received successful initial puncture, with the successful rate of initial puncture of 96.88%, and the cathetering-consuming time of( 99.5 ± 34.8) s;and 14 patients received puncture through femoral veins, among whom 14 succeed in initial puncture, with the successful rate of initial puncture of 14/14, and the cathetering-consuming time of (99.8 ± 44.8) s. None in treatment group had hematoma in puncture sites or arterial mis-puncture. Both groups finished deep veins puncture intubation successfully. Treatment group was markedly higher in the successful rate of initial puncture (P<0.05), notably shorter in cathetering-consuming time (P<0.05), and prominently lower in the total rate of complications than control group (P<0.05), and all differences were statistically significant. Conclusions Ultrasound localization based on isosceles right triangle theory has superiority to traditional B-ultrasound localization in deep veins puncture in that it can promote the successful rate of initial puncture and shorten cathetering-consuming time without increasing the occurrence rates of complications, and can be completely operated by single clinical physician independently, thus deserving to be popularized in clinical practice.