Mini reviews In this edition of Research review, we present two mini-reviews from Research Review Service’s publication: 10 Top Papers Not Reviewed by Research Review Service in 2012 – the full document is available at www.researchreviewservice.com. Whereas our regular column goes into more depth, detail and analysis, as well as focusing our readers on the clinical applications of the studies, these mini-reviews provide a more general overview of the research papers in question. Study #1: Painful shoulder and side of sleeping STUDY TITLE: Association between the side of unilateral shoulder pain and preferred sleeping position: A cross sectional study of 83 Danish patients AUTHORS: Kempf B and Kongsted A PUBLICATION INFORMATION: J Manipulative Physiol Ther 2012;35;407-412. Summary This cross-sectional study addressed a question that we encounter frequently in practice can sleeping position a ffect my shoulder pain? No evidence exists to support, nor refute, this theory. The authors evaluated adult patients seeking chiropractic care and with unilateral shoulder pain – the patients were asked about sleeping position and, if sleeping with a partner, which side of the bed they slept on. A total of 83 participants were included from 10 chiropractic clinics. Results This study shed some light on a relationship that, until this point, has been described with pure speculation or anecdote. Even though the sample size wasn’t huge (83 subjects), the results certainly reveal that clinicians should inquire about the preferred side for sleeping in patients with generalized shoulder pain. Although altering sleeping position may be di fficult, clinicians Could recommend switching sides of the bed (even temporarily to relieve pain) in those who sleep with a spouse or partner. Study #1: Core stability exercise and feed-forward activation of deep abdominal muscles in chronic LBP STUDY TITLE: Effect of core stability exercises on feed-forward activation of deep abdominal muscles in chronic low back pain: A randomized controlled trial AUTHORS: Vasseljen O et al. PUBLICATION INFORMATION: Spine 2012; 37(13): 1101-1108. Summary It is generally accepted that low back pain (LBP) may contribute to, or result from, motor control alterations in trunk/ abdominal musculature; however, the exact nature of this relationship remains unclear. Core stability exercises (CSEs) originally became popular in LBP treatment and rehabilitation based on observed changes in abdominal muscle activation patterns in LBP patients. Because deep trunk muscles contribute to stabilization of the spine, it is hypothesized that any deficit in feed-forward activation may increase one’s susceptibility to spinal injury or dysfunction. CSEs typically consist of low-load exercises emphasizing voluntary and isolated control of trunk muscles, which is assumed to help restore trunk motor Function. Overall, however, the evidence on the clinical e fficacy of CSE compared with other exercises is sparse for pain and disability, showing conflicting, or at best, small effects. The purpose of this randomized controlled trial was to investigate the effect of three different exercise interventions on feed-forward activation or timing of deep abdominal muscles in chronic LBP patients. Results Overall, very minor or no effects were found in onset after CSE treatment, meaning abdominal muscle onset was largely unaffected by eight weeks of exercises in chronic LBP patients. Further, there was no association between change in onset and LBP itself. Comments This was one of the first randomized trials investigating different loads and types of exercises, including CSEs, on abdominal muscle feed-forward activation (timing) in patients with chronic LBP. Unfortunately, the results add further doubt to the clinical importance of muscle activation “timing” in LBP. Clinicians should remember that prior research has demonstrated that deep abdominal muscles activate variably in both healthy and LBP populations. These large variations between individuals may justify exploration of differential effects in subgroups of LBP, but for now the exact manner in which we can utilize and interpret this information remains controversial. This does not mean that CSEs may not be effective, and it is well established that exercise (any type, really) is a very effective intervention for LBP! Get your patients moving! For current and previous research reviews by Shawn Thistle, please visit www.canadianchiropractor.ca. SHAWN THISTLE, BKIN HONS , DC, CSCS, practises full time in Toronto. He is the founder and president of Research Review Service Inc., an online, subscription-based service designed to help busy practitioners integrate current, relevant, scientific evidence into their practice (www.researchreviewservice.com).