Two percent of the US workforce has a compensable low back pain (LBP) injury each year with an estimated total? annual cost exceeding $20 billion. Approximately 40% of those who report an occurrence of LBP on the job associate? that injury with overexertion while lifting objects. There is a significant need for increased understanding of the? mechanisms of lifting tasks in order to improve programs for injury reduction.? Lifting injuries to the low back occur when mechanical stress exceeds the tolerance limits of the involved tissues? thereby producing excessive motion between spinal segments. The ability to adequately stabilize the segments of the? lumbar spine to prevent this excessive motion via coordinated muscular control is a common goal in low back exercise? programs. As the musculature of the abdominal cavity contracts around the abdominal contents, intra-abdominal? pressure (IAP) increases and converts the abdomen into a """"""""rigid cylinder"""""""" that has an increased stability compared to? the multi-segmented ligamentous spine. Several studies suggest that increases in IAP increase lumbar stability. As the? diaphragm forms the roof of the abdominal cavity, breath control can contribute to both respiration and IAP production.? Breath control has been shown to be directly related to IAP production as well as to direct in-vivo measures of lumbar? stability. The importance of coordination of the respiratory and motor systems during lifting tasks to achieve sufficient? lumbar stability has been suggested by multiple authors, although there has been almost no study of natural breath? control during lifting tasks exploring this issue. Increased understanding of the normal coordinative patterns of? respiratory and motor systems may allow improved training methods in exercise programs for lumbar stability and? contribute to both prevention and rehabilitation of low back pain due to lumbar instability.? Specific Aim 1: Develop novel methods of data collection and analysis of breath control patterns during lifting tasks? that can be used to determine if the timing, magnitude and direction of these patterns demonstrate theoretical support? for lumbar stability at critical moments of mechanical challenge.? Specific Aim 2: Determine the effects of different levels of challenge to lumbar stability (e.g., load, vertical height,? horizontal distance) during lifting tasks on the breath control patterns in healthy normal subjects.? Specific Aims 3: Determine the effects of different levels of challenge to lumbar stability (e.g., load, vertical height,? horizontal distance) during lifting tasks on the breath control patterns in patients with intermittent mechanical low back? pain.? Specific Aim 4: Determine if the patterns of breath control during lifting tasks used by patients with intermittent? mechanical low back pain differs when compared to breath patterns of normal subjects.? The research we propose will provide the first complete descriptions of breath control during lifting tasks and will be? the first to determine if significant differences in respiratory and motor system coordination exist between subjects with? and without low back pain. This pilot project data will provide estimates of effect size that can be used in the design of? larger related studies. This research has the potential to provide meaningful new information in the area of lifting tasks? and low back pain and have direct applications in the area of lumbar stability training to prevent or reduce low back pain.?
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