Sheri P. Silfies

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STUDY DESIGN Prospective observational study with a 2- to 3-year follow-up. OBJECTIVES To determine whether delayed muscle reflex response to sudden trunk loading is a result of or a risk factor for sustaining a low back injury (LBI). SUMMARY OF BACKGROUND DATA Differences in motor control have been identified in individuals with chronic low back pain(More)
OBJECTIVE To investigate alterations in trunk muscle timing patterns in subgroups of patients with mechanical low back pain (MLBP). Our hypothesis was that subjects with MLBP would demonstrate delayed muscle onset and have fewer muscles functioning in a feedforward manner than the control group. We further hypothesized that we would find differences between(More)
BACKGROUND It is hypothesized that injury or degeneration of osteoligamentous spinal structures would require compensation by trunk musculature and alterations in motor control to maintain spine stability. While, biomechanical modeling has supported this hypothesis, studies of muscle recruitment patterns in chronic low back pain patients both with and(More)
BACKGROUND Impaired proprioception in the lumbar spine has often been reported in people with low back pain. However, no prospective studies exist to assert the cause and effect of this association. We hypothesized that athletes with a history of low back injury (LBI) would demonstrate poorer lumbar position sense (PS) than athletes without a history of(More)
Postural control of the lumbar spine in unstable sitting was quantified through the analysis of the center of pressure (CoP) movement recorded by a force plate situated underneath a seat that incorporated a hemisphere. Thirteen healthy subjects were tested under conditions of increasing seat instability and elimination of visual input. The purpose of this(More)
There are conflicting findings in the literature regarding erector spinae activation imbalance in people with low-back pain (LBP). Some studies have found asymmetric recruitment between muscle pairs in people with LBP, whilst other studies have not; some reported people with LBP recruit more lumbar muscles whilst other have reported greater thoracic(More)
“(1) Evolution is a passage from the most to the least organized; that is to say, from the lowest, well-organized centers, up to the highest, least-organized centers; putting this otherwise, the progress is from centers comparatively well organized at birth up to those, the highest centers, which are continually organizing through life. (2) Evolution is a(More)
The authors investigated differences in trunk muscle activation timing between patients with chronic nonspecific low back pain (NSLBP) and asymptomatic controls during a self-initiated postural challenge. The authors compared 30 participants with NSLBP to 30 controls. Surface electromyographic data were collected from bilateral trunk muscles. Dependent(More)
The purpose of this study was to quantify lumbo-pelvic control differences between patients with mechanical low back pain (MLBP) and asymptomatic controls using a dynamical systems approach to data reduction and interpretation. Subjects were 30 patients with chronic MLBP (age: 41.1+/-8.9 years, body mass index: 26.2+/-5.2 kg/m(2)) and 35 asymptomatic(More)
Lumbar stabilization or ‘core’ stabilization ex­ercises are currently popular interventions for patients with mechanical low back pain (MLBP). Stabilization ex­ercises have typically been prescribed for patients with ‘spinal instability.’ But can we actually identify patients with spinal instability, and are these patients likely to benefit from(More)