Do NIRS measures relate to subjective low back discomfort during sedentary tasks?

作者：Callaghan Jack P^*; Gregory Diane E; Durkin Jennifer L

来源：International Journal of Industrial Ergonomics, 2010, 40(2): 165-170.

DOI：10.1016/j.ergon.2009.01.006

• Seated work
• Prolonged exposure
• Cumulative loading
• Low back discomfort

Sedentary tasks such as sitting or standing are often a required task components of industrial occupations. Due to automation, industrial job changes to more computer based tasks, and job ergonomic (re)design, the exposure to heavy lifting and awkward postures is being reduced and subsequently resulting in increased duration of work time spent in sedentary non-varying postures. Prolonged standing and seated exposures have been associated with the reporting of low back pain however the mechanism of this discomfort is not well understood. The purpose of this study was to determine whether muscle deoxygenation was one possible mechanism for the development of low back discomfort (LED) during standing and seated exposures. It was hypothesized that during a prolonged exposure period. LED would develop and the muscle oxygen saturation levels measured using near infrared spectroscopy (NIRS) would change over time. Sixteen individuals stood for 2 h and eight participants were exposed to 1 h of simulated driving while back extensor muscle oxygenation was monitored over time. Eighty-two percent of the participants developed LED as a result of the prolonged standing and seated protocols, which significantly increased over the exposure period (p < 0.0001). The NIRS measures over the right lumbar erector spinae were not significantly altered over time, had average levels above baseline resting values of oxygen saturation, and exhibited poor correlations with the perceived low back discomfort scores (r = 0.07-0.47) for standing and seated exposures respectively. These findings support the notion that the mechanism of LED from exposure to sedentary tasks is not attributable to prolonged low-level static muscle activations that could occlude blood flow and the delivery of oxygen to working muscles.
Relevance to industry: Seated and standing postures are a common task component in the majority of industrial occupations. While these tasks are often viewed as being non-injurious, increased exposure durations and non-varying postures have been associated with high levels of low back discomfort. This study examined muscle oxygenation levels to assess if static muscle activation was a potential contributor to the development of low back pain.

• 出版日期2010-3