Alteration and Recovery of Lumbar Spine Mechanics to Flexed Postures

点击翻译按钮获取中文摘要

Society has become aware that sitting for long periods of time is bad. While researchers have shown that sitting is linked with higher risk of developing diseases and earlier death in the long-term, relatively little is known about the short-term effects. Sitting involves a great amount of bending in the spine that directly affects the muscles, nerves and joints of the low back. Changes to these structures can lead to injury resulting in significant impacts on quality of life, the ability to work and productivity levels. It is also interesting that, within the healthy population, some individuals seem to be able to sit extensively without issue whereas others cannot.******Currently, we know that long periods in a posture where the back is totally bent causes the spine to become more flexible, lengthens the time it takes for muscles to turn on to protect joints and can cause inflammation in the ligaments of the spine. There is also evidence that the reversal of the above changes takes more than twice the time it took to create them. Applying these research findings to sitting is not completely correct since most work has only looked at maximum bending whereas sitting involves less extreme bending. Similarly, when appropriate postures have been examined, the testing length has been brief and not comparable to real job situations. To date, no researchers have looked at differences between sitting tolerant and intolerant individuals in the healthy population. ******To address these questions, this program will use healthy, human subjects to investigate changes to the low back, and their persistence, in response to sitting with exposure times and seating types relevant to the workplace. Specifically, changes in back flexibility and muscle activity will be measured and compared between different seats (office, automobile and sit/stand stools), between sitting tolerant/intolerant individuals and between durations (hours, days and one week). ******The anticipated outcomes of this research program include the determination of: (1) differences in flexibility and/or muscle function between sitting tolerant and intolerant individuals, (2) flexibility and muscle function response to various seating types and exposure times and (3) the persistence of flexibility and muscle changes after short (hours, day) and medium (week) exposures to office sitting.******These results will directly lead to targeted workplace interventions and the ability to design appropriate work/rest strategies and evidence-based guidelines to limit exposure to sitting in the workplace. Further, it will contribute to research by providing important information on how the effects of sitting accumulate and persist over time. Since the majority of Canadians spend most of their day sitting at work, the results of this research will have far reaching effects, improving the productivity and performance of workers, and ultimately benefiting the economy and industry.**