Força e equilíbrio de mulheres idosas com osteoporose praticantes de Pilates

Objective:to evaluate the strength and balance of women over 50 years old, with osteoporosis,Pilates practitioners,in the city of Pirapora -MG. Materials and Methods: it is a descriptive, cross-sectional study, with conveniencesampling, represented by 10 elderly women with osteoporosis,who practice Pilates. Lower limb strength was assessed by means ofthe Sit and Stand test;static balance, byusing the Flamingo Position test;and dynamic balance,withthe Timed Up and Gotest. Results:the Sit and Stand Chair test,with an average of 8.4±2.7 repetitions, indicated “risk zone” for the development of dependence on activities of daily life. In the Flamingo Position test, the most frequent oscillation values were fixed at the “Strong” level,with 4.2±1.4 oscillations in60 seconds, indicating good performance. The Timed Up and Gotest presentedperformances inan average of 12.7±2.4 seconds, indicating “low risk for falls”. Conclusion:elderly women with osteoporosis, Pilates practitioners, presented weakness of the lower limbs but good static and dynamic balance. Even with a low risk of developing falls, they remain in the “risk zone” to develop dependence on daily activities.

Study on temperature rise in the screw pair under high frequent oscillation

Purpose – This paper aims to study the mechanism of heat generation in a screw, and investigates the heat flux in the connection screw pair under high frequent oscillation along the axial direction. Heat generated in the screw under high frequent oscillation could be observed in a lot of situations and was significant, and it could cause damage of screw joining and transmission. Design/methodology/approach – A heat flux model in a screw pair under high frequent oscillation along the axial direction is established. Bulk temperature field in the connected parts is calculated by means of finite element methods. A testing device aimed to temperature rise measurement in a thread pair under high frequent oscillation is built. Temperature rises under different operation conditions are measured. Findings – The heat flux generated in the screw pair because of friction between the contact surfaces of the screw thread is obtained. The effects of oscillating amplitude and frequency on heat flux are obtained. It is found that amplitude and frequency have a significant influence on the heat generated under high frequent oscillation. The numerical results show good agreement with the numerical results. Research limitations/implications – This study has some limitations; for example, the friction coefficient and the relative sliding displacement between the thread surfaces need further accurate research. Practical implications – Heat generated in a screw under high frequent oscillation is very rarely mentioned in previous research papers. The methods used in this paper could be used to evaluate the heat flux and temperature under high frequent oscillations. The temperature could be used to calculate the thermal stress and expansion in the screw thread under high frequent oscillation. The screw connections need to be protected from the damage because of heat stress and from getting loose because of heat expansion of the connected parts. Originality/value – The mechanisms of heat generation in the screw pair under high frequent oscillation are studied. The model of heat flux in the screw under high frequency oscillation is established, and it could be used to calculate the heat flux under different operating conditions. The transient temperature field of the connected parts is given. A test facility was built and the experiment to measure the temperatures of the bolt and nut was carried out. The results had good agreement.