The descriptive epidemiology of sitting in Chilean adults: Results from the National Health Survey 2009-2010

Background: Although evidence on the health effects of sedentary behavior(SB) has grown systematically in recent years, few developing countries have reported population levels of SB, especially in South America. Our objective was to describe time spent sitting in a representative sample from Chile categorized by age, gender, educational level, and body mass index(BMI).Methods: A national health survey was conducted in Chile in a nationally representative sample(n = 5411) in 2009-2010. Sitting time(ST) was measured with the Global Physical Activity Questionnaire Version 2.Results: Data were from 5031 participants(43.26±0.41 years, mean±SE; 40.3% male). Overall, there were no gender differences in mean ST(men: 158.10±5.80 min/day, women 143.45±4.77 min/day; p = 0.05). ST was lower in those who lived in rural areas compared with urban areas(99.4 min/day vs. 160.0 min/day; p = 0.001). ST increased significantly with increasing BMI, but only in men(p = 0.009), and was positively related to years of education in both men and women(p < 0.0001).Conclusion: The findings were different from those reported in other countries and contexts, reinforcing the need for international surveillance and monitoring over time to inform policy makers. Differences in ST across different groups emphasize the need to develop tailored messages and interventions for reducing ST in different population subgroups.

Lumbar and neck injuries of occupants in different reclining postures

Purpose:With the increasing level of automation in automobiles,the advent of autonomous vehicles hasreduced the tendency of drivers and passengers to focus on the task of driving.The increasing automation in automobiles reduced the drivers'and passengers'focus on driving,which allowed occupants tochoose a more relaxed and comfortable sitting position.Meanwhile,the occupant's sitting position wentfrom a frontal,upright position to a more relaxed and reclined one,which resulted in the existing restraint systems cannot to keep occupants safe and secure.This study aimed to determine the effects ofdifferent reclining states on occupants'lumbar and neck injuries.Methods:This is an original research on the field of automotive safety engineering.Occupants indifferent initial sitting positions(25°,35°,45°,and 55°)were adapted to changes in seat back angle andrestraint systems and placed in the same frontal impact environment.Neck injury indexes,lumbar axialcompression force and acceleration,as well as occupant dynamic response during the impact,werecompared in different sitting positions.The injury response and kinematic characteristics of occupants indifferent reclining positions were analyzed by the control variable method.Results:As the sitting angle increased,the occupant's head acceleration decreased,and the forward-leanangle decreased.Occupants in the standard sitting position had the greatest neck injury,with an Nij of0.95,and were susceptible to abbreviated injury scale 2+cervical medullary injuries.As the seatbackangle increased,the geometric position of the lumbar spine tended to be horizontal,and the impact loadtransmitted greater forces to the lumbar spine.The occupant's lumbar injury was greatest in the lyingposition,with a peak axial compression force on the lumbar region of 5.5 KN,which was 2.3 KN greaterthan in the standard sitting position.Conclusion:The study of occupant lumbar and neck injuries based on different recline states can providea theoretical basis for optimizing lumbar evaluation indexes,which is conducive to the understanding ofthe lumbar injury mechanism and the comprehensive consideration of occupant safety protection.