A PILOT STUDY ON PROBLEMS WITH WOMEN'S ATHLETIC SUPPORTIVE WEAR

INTRODUCTION: A study was conducted to investigate some of the discomfort women experienced with athletic supportive wear (sports bras) while playing soccer. Players from a recreational women's soccer league were surveyed. The objective of the survey was to identify specific biomechanical problems female soccer players encountered during the game with their supportive wear. This investigation was conducted as a pilot study for a full-scale analysis of discomfort caused by the design of women's supportive wear. METHODS: Questionnaires were distributed to 35 players in a recreational women's soccer league in Madison, Wisconsin, U.S.A.. The respondents were asked to identify discomfort they encountered while playing soccer with regular and athletic supportive wear. The return rate was 40 % with 14 returned surveys. The ages, heights, weights, bust sizes, and cup sizes (converted to the difference between bust size and circumference of the trunk beneath the breasts) of the respondents are shown in Table 1. RESULTS: The major discomfort reported by respondents who had played soccer in regular supportive wear were lack of support (50%), heat (33%), excessive perspiration (33%), and friction on the skin (22%). For playing soccer in athletic supportive wear, 5 respondents (25.71%) reported no discomfort; the others listed the following as the major discomfort: heat (57%), excessive perspiration (36%), excessive tightness (28%), and friction on the skin (14%). CONCLUSIONS: Athletic supportive appeared to improve the support of the breasts for female recreational soccer players in this survey. The wearers’ breasts ‘bounced’ less. However, the supportive wear also increased the discomfort caused by the accumulation of body heat. Excessive perspiration and friction on the skin remained problematic. Furthermore, excessive tightness became a new discomfort for some players. The data collected in the study may serve as a source for detailed biomechanical studies and complete analysis of the discomfort caused by athletic supportive wear worn by female athletes in different sports

A Dynamic Absorber for Gear Systems Operating in Resonance and Instability Regions

There are many practical situations where resonances and instabilities in piniongear systems are difficult to predict in the design stage due to the unreliability of estimating the mesh stiffness and damping parameters. This paper presents a procedure for the design of an optimal dynamic absorber system which can be used in conditions where preliminary analysis shows that high dynamic tooth loads are likely to occur. The optimal parameters for the absorber are given in a generalized form in order to simplify its design for a particular gear system. Introduction In the previous paper (reference The dynamic equations of motion for the absorber system are developed in non-dimensional form to determine the pertinent variables necessary for general description of the absorber system. The conditions for uncoupling these equations are specified. The decision parameters to be considered in the optimization of the design are specified. A pattern search is employed to evaluate the optimal parameters for different gear system conditions and the results are given as design charts. The response of the optimal absorber shows its effectiveness even when the theoretical uncoupling conditions are not met

Topology optimization for the seismic design of truss-like structures

A practical optimization method is applied to design nonlinear truss-like structures subjected to seismic excitation. To achieve minimum weight design, inefficient material is gradually shifted from strong parts to weak parts of a structure until a state of uniform deformation prevails. By considering different truss structures, effects of seismic excitation, target ductility and buckling of the compression members on optimum topology are investigated. It is shown that the proposed method could lead to 60% less structural weight compared to optimization methods based on elastic behavior and equivalent static loads, and is efficient at controlling performance parameters under a design earthquake. © 2010 Elsevier B.V