Thrust Technique

Abstract: It is shown that the thrust, T , exerted by a jet on the tube from which it flows, and the corresponding die-swell ratio, D , are closely related and dependent on the axial velocity and stress profiles at the exit plane. Velocity-profile data, calculated by Tanner using a finite element method, have been used to demonstrate that for a Newtonian liquid the reduction in measured thrust from the expected value arises from a re-arranged, non-parabolic axial velocity profile and the related re-arranged non-zero axial stress profile at the exit plane. The axial stress re-arrangement is the major effect. Using the correction-curve thus derived to determine the normal stresses, ν 1 + 1 2 ν 2 aqueous and non-aqueous polymer solutions gives values that are higher than the “correct” results by a significant, substantial amount. The difference is not due to neglect of the second normal stress difference, ν 2 , nor to the neglect of the wall pressure at the exit plane, which is shown experimentally to be very small. It is suggested that the difference, which is a function only of the shear stress (or rate of shear) at the wall, may arise from a difference in the stress profile associated with the velocity re-arrangement at the exit between Newtonian liquids and elasticoviscous liquids for which the extensional viscosity may be high.

Abstract: Background: The study of injuries stemming from sacroiliac dysfunction in athletes has been discussed in many papers However, the treatment of this issue through thrust and muscle-energy techniques has hardly been researched The objective of our research is to compare the effectiveness of thrust technique to that of energy muscle techniques in the resolution of sacroiliac joint blockage or dysfunction in middle-distance running athletes Methods: A quasi-experimental design with three measures in time (pre-intervention, intervention 1, final intervention after one month from the first intervention) was made The sample consisted of 60 adult athletes from an Athletic club, who were dealing with sacroiliac joint dysfunction The sample was randomly divided into three groups of 20 participants (43 men and 17 women) One intervention group was treated with the thrust technique, another intervention group was treated with the muscle–energy technique, and the control group received treatment by means of a simulated technique A prior assessment of the range of motion was performed by means of a seated forward flexion test, a standing forward flexion test, and the Gillet test After observing the dysfunction, the corresponding technique was performed on each intervention group The control group underwent a simulated technique A second intervention took place a month later, in order to ascertain possible increased effectiveness Results: Statistically significant differences were found between the muscle energy technique (MET) and muscle energy groups compared with the placebo group in both interventions (p = 0000), with a significant reduction in positive dysfunction (initially 20 in all groups, eight in MET group, and two in thrust group in the final intervention) Comparing the changes in time, only the thrust group obtained statistically significant differences (p = 0000, with a reduction of positive dysfunction, starting at 20 positives, five positive in the initial intervention and two positive in the final intervention) and when comparing both techniques, it was observed that between the first intervention and the final intervention, the thrust technique was significantly higher than the MET technique (p = 0032) Conclusions: The thrust manipulation technique is more effective in the treatment of sacroiliac dysfunction than the energy muscle technique, in both cases obtaining satisfactory results with far middle-distance running athletes Finally, the thrust technique showed positive results in the first intervention and also in the long term, in contrast to the MET technique that only obtained changes after the first intervention