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Stephen H M Brown - One of the best experts on this subject based on the ideXlab platform.

  • architectural analysis and predicted functional capability of the human latissimus dorsi muscle
    Journal of Anatomy, 2013
    Co-Authors: Michael E Gerling, Stephen H M Brown
    Abstract:

    The latissimus dorsi is primarily considered a muscle with actions at the shoulder, despite its widespread attachments at the Spine. There is some dispute regarding the potential contribution of this muscle to lumbar Spine function. The architectural design of a muscle is one of the most accurate predictors of muscle function; however, detailed architectural data on the latissimus dorsi muscle are limited. Therefore, the aim of this study was to quantify the architectural properties of the latissimus dorsi muscle and model mechanical function in light of these new data. One latissimus dorsi muscle was removed from each of 12 human cadavers, separated into regions, and micro-dissected for quantification of fascicle length, sarcomere length, and physiological cross-sectional area. From these data, sarcomere length operating ranges were modelled to determine the force-length characteristics of latissimus dorsi across the Spine and shoulder ranges of motion. The physiological cross-sectional area of latissimus dorsi was 5.6±0.5 cm2 and normalized fascicle length was 26.4±1.0 cm, indicating that this muscle is designed to produce a moderate amount of force over a large range of lengths. Measured sarcomere length in the post-mortem Neutral Spine posture was nearly optimal at 2.69±0.06 μm. Across Spine range of motion, biomechanical modelling predicted latissimus dorsi acts across both the ascending and descending limbs of the force-length curve during lateral bend, and primarily at or near the plateau region (where maximum force generation is possible) during flexion/extension and axial twist. Across shoulder range of motion, latissimus dorsi acts primarily on the plateau region and descending limbs of the force length curve during both flexion/extension and abduction/adduction. These data provide novel insights into the ability of the latissimus dorsi muscle to generate force and change length throughout the Spine and shoulder ranges of motion. In addition, these findings provide an improved understanding of the Spine and shoulder positions at which the force-generating capacity of this muscle can become jeopardized, and consequently how this may affect its Spine-stabilizing ability.

  • architectural and morphological assessment of rat abdominal wall muscles comparison for use as a human model
    Journal of Anatomy, 2010
    Co-Authors: Stephen H M Brown, Karina Banuelos, Samuel R Ward, Richard L Lieber
    Abstract:

    The abdominal wall is a composite of muscles that are important for the mechanical stability of the Spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague-Dawley rats were killed and formalin-fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross-sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the Neutral Spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force-generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague-Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions.

  • effects of abdominal muscle coactivation on the externally preloaded trunk variations in motor control and its effect on Spine stability
    Spine, 2006
    Co-Authors: Stephen H M Brown, Francisco J Veragarcia, Stuart M Mcgill
    Abstract:

    STUDY DESIGN: A repeated measures biomechanical analysis of the effects of abdominal bracing in preparation for a quick release of the loaded trunk. OBJECTIVES: To quantify the ability of individuals to abdominally brace the externally loaded trunk, and assess their success in achieving and enhancing appropriate Spine stability. SUMMARY OF BACKGROUND DATA: Spine stability requires trunk muscle coactivation, which demands motor control skill that differs across people and situations. The quick release protocol may offer insight into the motor control scheme and subsequent effect on Spine stability. METHODS: There were 10 individuals who sat, torso upright, in an apparatus designed to foster a Neutral Spine position. They were instructed to support a posteriorly directed load to the trunk in either their naturally chosen manner, or by activating the abdominal muscles to 10%, 20%, or 30% of maximum ability. The externally applied load was then quickly released, thereby unloading the participant. Muscle pre-activation patterns, Spine stability, and kinematic measures of trunk stiffness were quantified. RESULTS: Participants were able to stabilize their Spine effectively by supporting the load in a naturally selected manner. Conscious, voluntary overdriving of this natural pattern often resulted in unbalanced muscular activation schemes and corresponding decreases in stability levels. CONCLUSIONS: Individuals in an externally loaded state appear to select a natural muscular activation pattern appropriate to maintain Spine stability sufficiently. Conscious adjustments in individual muscles around this natural level may actually decrease the stability margin of safety.

Andrew R Karduna - One of the best experts on this subject based on the ideXlab platform.

  • trunk muscle recruitment patterns in specific chronic low back pain populations
    Clinical Biomechanics, 2005
    Co-Authors: Sheri P Silfies, Dawn Squillante, Philip Maurer, Sarah Westcott, Andrew R Karduna
    Abstract:

    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 without significant osteoligamentous damage have been limited. This study utilized a non-randomized case-control design to investigate trunk muscle recruitment patterns around the Neutral Spine position between subgroups of patients with chronic mechanical low back pain and asymptomatic controls. Methods. Twenty subjects with chronic low back pain attributed to clinical lumbar instability were matched to 20 asymptomatic controls. In addition 12 patients with non-specific chronic low back pain were studied. Surface EMG from five trunk muscles was analyzed to determine activation levels and patterns of recruitment during a standing reach under two different loading conditions. Findings. The chronic low back pain group with symptoms attributed to clinical instability demonstrated significantly higher activation levels of the external oblique and rectus abdominus muscles and lower abdominal synergist ratios than the control group. No significant differences were found between patient subgroups. Interpretation. While these data demonstrate altered muscle recruitment patterns in patients with chronic low back pain, the changes are not consistent with Panjabis theory suggesting that these alterations are driven by passive subsystem damage. However, the higher activation of global abdominal musculature and altered synergist patterns may represent a motor control pattern that has consequences for continued dysfunction and chronic pain. 2005 Elsevier Ltd. All rights reserved.

Myers Mary - One of the best experts on this subject based on the ideXlab platform.

  • 90-Degree Hold
    DigitalCommons@IMSA, 2019
    Co-Authors: Myers Mary
    Abstract:

    Lie on your back in Neutral Spine, with your legs extended up toward the ceiling. Align the ankles, knees and hips. Arms rest on the mat alongside the body with the palms facing down.https://digitalcommons.imsa.edu/pilates_crit_inst/1001/thumbnail.jp

  • Neutral Spine
    DigitalCommons@IMSA, 2019
    Co-Authors: Myers Mary
    Abstract:

    Begin lying on your back with knees bent, feet hip-distance apart and flat on the floor. Place the arms along the sides of the body with the palms down. The back, pelvis and Spine should be in a Neutral position.https://digitalcommons.imsa.edu/pilates_crit_inst/1020/thumbnail.jp

  • 45 Degree Hold
    DigitalCommons@IMSA, 2019
    Co-Authors: Myers Mary
    Abstract:

    Lie on your back in Neutral Spine, with your legs extended up toward the ceiling. Align the ankles, knees and hips. Arms rest on the mat alongside the body with the palms facing down. Make certain to maintain Pilates feet. Head may be down.https://digitalcommons.imsa.edu/pilates_crit_inst/1000/thumbnail.jp

  • Bridge
    DigitalCommons@IMSA, 2019
    Co-Authors: Myers Mary
    Abstract:

    Lie on your back in Neutral Spine, with your knees bent and feet on the floor. Place your feet a foot length away from and in line with your hips. Your knees should be in line with your hips. Anchor your palms and shoulder blades into the mat. Inhale: Press down through your feet to lengthen your Spine and press your hips up. You will come to a bridge position on your shoulders with your knees, hips and shoulders in one line. Your abs and hamstrings should be well engaged.https://digitalcommons.imsa.edu/pilates_crit_inst/1003/thumbnail.jp

  • Hot Potato
    DigitalCommons@IMSA, 2019
    Co-Authors: Myers Mary
    Abstract:

    Lie on your back in Neutral Spine, with your arms by the sides of your body. Exhale and slowly raise your legs and overhead. Keep the arms by the sides of the body and ensure that the shoulders are pulled down towards the back. Inhale when you reach the top point of the movement. Exhale and let the legs create a semicircle together in the air. Repeat this movement. Make certain to keep a continuous even flow to your movements and work each side of the body evening. Work towards raising the torso up and overhead with the legs. Slowly bring your torso and buttocks back down on the floor as you complete the semicircle. As your tailbone touches the floor, slowly inhale and repeat the movement, lifting your legs and torso above your head and this time making the semicircle in the opposite direction.https://digitalcommons.imsa.edu/pilates_crit_inst/1015/thumbnail.jp

Sheri P Silfies - One of the best experts on this subject based on the ideXlab platform.

  • trunk muscle recruitment patterns in specific chronic low back pain populations
    Clinical Biomechanics, 2005
    Co-Authors: Sheri P Silfies, Dawn Squillante, Philip Maurer, Sarah Westcott, Andrew R Karduna
    Abstract:

    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 without significant osteoligamentous damage have been limited. This study utilized a non-randomized case-control design to investigate trunk muscle recruitment patterns around the Neutral Spine position between subgroups of patients with chronic mechanical low back pain and asymptomatic controls. Methods. Twenty subjects with chronic low back pain attributed to clinical lumbar instability were matched to 20 asymptomatic controls. In addition 12 patients with non-specific chronic low back pain were studied. Surface EMG from five trunk muscles was analyzed to determine activation levels and patterns of recruitment during a standing reach under two different loading conditions. Findings. The chronic low back pain group with symptoms attributed to clinical instability demonstrated significantly higher activation levels of the external oblique and rectus abdominus muscles and lower abdominal synergist ratios than the control group. No significant differences were found between patient subgroups. Interpretation. While these data demonstrate altered muscle recruitment patterns in patients with chronic low back pain, the changes are not consistent with Panjabis theory suggesting that these alterations are driven by passive subsystem damage. However, the higher activation of global abdominal musculature and altered synergist patterns may represent a motor control pattern that has consequences for continued dysfunction and chronic pain. 2005 Elsevier Ltd. All rights reserved.

Robert William Martin Van Deursen - One of the best experts on this subject based on the ideXlab platform.

  • spinal position sense and trunk muscle activity during sitting and standing in nonspecific chronic low back pain classification analysis
    Spine, 2012
    Co-Authors: Liba Sheeran, Valerie Sparkes, Bruce Caterson, Monica Bussemorris, Robert William Martin Van Deursen
    Abstract:

    Study Design. A cross-sectional study between subgroups of nonspecific chronic low back pain (NSCLBP) and asymptomatic controls. Objective. To investigate NSCLBP subgroup differences in spinal position sense and trunk muscle activity when repositioning thoracic and lumbar Spine into Neutral (midrange) spinal position during sitting and standing. Summary of Background Data. Patients with NSCLBP report aggravation of symptoms during sitting and standing. Impaired motor control in NSCLBP, associated with sitting and standing postures nearer the end range of spinal motion, may be a contributing factor. Rehabilitation improving Neutral (midrange) spinal position control is advocated. Postural and motor control alterations vary in different NSCLBP subgroups, potentially requiring specific postural interventions. There is limited evidence on whether subgroup differences exist when performing Neutral Spine position tasks. Methods. Ninety patients with NSCLBP and 35 asymptomatic controls were recruited. Two blinded practitioners classified NSCLBP into subgroups of active extension pattern and flexion pattern. Participants were assisted into Neutral Spine position and asked to reproduce this position 4 times. Absolute, variable, and constant errors were calculated. Three-dimensional thoracic and lumbar kinematics quantified the repositioning accuracy and surface electromyography assessed back and abdominal muscles activity bilaterally. Results. Irrespective of subclassification, patients with NSCLBP produced significantly greater error magnitude and variability than the asymptomatic controls, but subgroup differences were detected in the error direction. Subgroup differences in the trunk muscle activity were not consistently identified. Although both subgroups produced significantly higher abdominal activity, subclassification revealed difference in superficial multifidus activity during standing, with flexion pattern producing significantly greater activity than the asymptomatic controls. Conclusion. Subgroups of NSCLBP had similar Neutral spinal position deficits regarding error magnitude and variability, but subclassification revealed clear subgroup differences in the direction of the deficit. The trunk muscle activation was shown to be largely nondiscriminatory between subgroups, with the exception of superficial lumbar multifidus.