OBJECTIVE To investigate the possible influences of saddle type on the incidence of "lower back pain" in a cross section of equestrian riders. METHODS 108 equestrian riders completed a questionnaire concerning their riding habits and whether they suffered from lower back pain. In particular they were asked whether they used a traditional style/general purpose saddle (GP) or a deep seated/West...

To compute the maximum likelihood estimates the log-likelihood function L is maximized with respect to all model parameters. To check that the maximization has been achieved two things have to be satisfied: 1. The vector of first derivatives with respect to the model parameter L′ should be equal to 0. 2. The negative of the matrix of the second derivatives −L′′ should be a positive definite mat...

A saddle point variational (SPV ) method was applied to the Dirac equation as an example of a fully relativistic equation with both negative and positive energy solutions. The effect of the negative energy states was mitigated by maximizing the energy with respect to a relevant parameter while at the same time minimizing it with respect to another parameter in the wave function. The Cornell pot...

REASONS FOR PERFORMING STUDY Although the saddle is seen as one of the biggest causes of back pain, and weightbearing is seen as an important aetiological factor in 'kissing spine' syndrome (KSS), the effects of a saddle and weight on the back movements of the horse have never been studied. OBJECTIVE To determine the effects of pressure on the back, exerted by tack and weight, on movements of...

Saddle-node bifurcations arise frequently in solitary waves of diverse physical systems. Previously it was believed that solitary waves always undergo stability switching at saddle-node bifurcations, just as in finite-dimensional dynamical systems. Here we show that this is not true. For a large class of generalized nonlinear Schrödinger equations with real or complex potentials, we prove that ...

REASONS FOR PERFORMING STUDY A comprehensive kinematic description of rider and saddle movements is not yet present in the scientific literature. OBJECTIVE To describe saddle and rider movements in a group of high-level dressage horses and riders. METHOD Seven high-level dressage horses and riders were subjected to kinematic measurements while performing collected trot on a treadmill. For a...

PURPOSE Repetitive internal stress in the perineum has been associated with soft-tissue trauma in bicyclists. Using an engineering approach, the purpose of this study was to quantify the amount of compression exerted in the perineum for a range of saddle widths and orientations. METHODS Computer tomography was used to create a three-dimensional voxel-based finite element model of the right si...

In this note, we discuss the convergence behavior of a modified inexact Uzawa algorithm for solving generalized saddle point problems, which is an extension of the result obtained in a recent paper [Z.H. Cao, Fast Uzawa algorithm for generalized saddle point problems, Appl. Numer. Math., 46 (2003) 157-171]. Keywords—Saddle point problem; Inexact Uzawa algorithm; Convergence behavior.

Necessary and sufficient conditions for existence and uniqueness of solutions are developed for twofold saddle point problems which arise in mixed formulations of problems in continuum mechanics. This work extends the classical saddle point theory to accommodate nonlinear constitutive relations and the twofold saddle structure. Application to problems in incompressible fluid mechanics employing...

Saddle position affects mechanical variables during submaximal cycling, but little is known about its effect on mechanical performance during maximal cycling. Therefore, this study relates saddle position to experimentally obtained maximal power output and theoretically calculated moment generating capacity of hip, knee and ankle muscles during isokinetic cycling. Ten subjects performed maximal...