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Paul W Hodges - One of the best experts on this subject based on the ideXlab platform.

  • morphology of the abdominal muscles in ballet dancers with and without low back pain a magnetic resonance imaging study
    2014
    Co-Authors: Jan E Gildea, Julie A Hides, Paul W Hodges
    Abstract:

    Abstract Objectives To evaluate the morphology of transversus abdominis and obliquus internus abdominis muscles and the ability to “draw in” the abdominal wall, in professional ballet dancers without low back pain, with low back pain or both Hip Region and low back pain. Design Observational study. Methods Magnetic resonance images of 31 dancers were taken at rest and during voluntary abdominal muscle contraction. Measurements included the thickness of transversus abdominis and obliquus internus abdominis muscles, lateral slide of the anterior extent of the transversus abdominis muscles (transversus abdominis slide) and reduction in total cross sectional area of the trunk. Results The transversus abdominis and obliquus internus abdominis muscles were thicker in male dancers and the right side was thicker than the left in both genders. There was no difference in muscle thickness as a proportion of the total thickness, between dancers with and without pain, although there was a trend for female dancers with low back pain only to have a smaller change in transversus abdominis muscle thickness with contraction than those without pain. Transversus abdominis slide was less in female dancers than in male dancers. When gender was ignored, the extent of transversus abdominis slide was less in dancers with low back pain only. Reduction in trunk cross sectional area with contraction was not different between genders or groups. Conclusions This study provides evidence that the abdominal muscles (transversus abdominis and obliquus internus abdominis) are asymmetrical in dancers and although the abdominal muscles are not different in structure (resting thickness) in dancers with LBP, there is preliminary evidence for the behavioural change of reduced slide of transversus abdominis during the ‘draw in’ of the abdominal wall.

  • size and symmetry of trunk muscles in ballet dancers with and without low back pain
    2013
    Co-Authors: Jan E Gildea, Julie A Hides, Paul W Hodges
    Abstract:

    Study Design Cross-sectional, observational study. Objectives To investigate the cross-sectional area (CSA) of trunk muscles in professional ballet dancers with and without low back pain (LBP). Background LBP is the most prevalent chronic injury in classical ballet dancers. Research on nondancers has found changes in trunk muscle size and symmetry to be associated with LBP. There are no studies that examine these changes in ballet dancers. Methods Magnetic resonance imaging was performed in 14 male and 17 female dancers. The CSAs of 4 muscles (multifidus, lumbar erector spinae, psoas, and quadratus lumborum) were measured and compared among 3 groups of dancers: those without LBP or Hip pain (n = 8), those with LBP only (n = 13), and those with both Hip-Region pain and LBP (n = 10). Results Dancers with no pain had larger multifidus muscles compared to those with LBP at L3–5 (P<.024) and those with both Hip-Region pain and LBP at L3 and L4 on the right side (P<.027). Multifidus CSA was larger on the left s...

René M. Rossi - One of the best experts on this subject based on the ideXlab platform.

  • validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage
    2017
    Co-Authors: Patrick D. Wettenschwiler, Stephen J. Ferguson, Simon Annaheim, Silvio Lorenzetti, Rolf Stämpfli, Agnes Psikuta, René M. Rossi
    Abstract:

    Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R2>0.5) in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a Hip belt, were assessed. The mechanical parameters were measured in the shoulder and the Hip Region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg), combined with four different Hip belt tensions (30N, 60N, 90N, and 120N). Through the significant (p<0.05) correlation of the mechanical parameters measured on the dummy with the corresponding values of the subject study, the dummy was validated for all static measurements and for dynamic measurements in the Hip Region to accurately simulate the interaction between the human body and the load carriage system. Multiple linear regressions with the mechanical parameters measured on the dummy as independent variables and the corresponding subjective discomfort scores from the subject study as the dependent variable revealed a high predictive power of the instrumented dummy. The dummy can explain 75% or more of the variance in discomfort using average pressures as predictors and even 79% or more of the variance in discomfort using strap forces as predictors. Use of the dummy enables objective, fast, and iterative assessments of load carriage systems and therefore reduces the need for labor-intensive subject studies in order to decrease the mechanical aspects of discomfort during load carriage.

  • Validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage
    2017
    Co-Authors: Patrick D. Wettenschwiler, Stephen J. Ferguson, Simon Annaheim, Silvio Lorenzetti, Rolf Stämpfli, Agnes Psikuta, René M. Rossi
    Abstract:

    Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R2>0.5) in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a Hip belt, were assessed. The mechanical parameters were measured in the shoulder and the Hip Region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg), combined with four different Hip belt tensions (30N, 60N, 90N, and 120N). Through the significant (p

Ron Andrews - One of the best experts on this subject based on the ideXlab platform.

  • differential diagnosis of a femoral neck head stress fracture
    2006
    Co-Authors: Burke Gurney, William G Boissonnault, Ron Andrews
    Abstract:

    Study Design Resident's case problem. Background Identifying stress fractures of the Hip can be a challenging differential diagnosis. Pain presentation is not always predictable and radiographs may not show the fracture, especially during its early stages. Hip stress fractures left untreated can displace and necessitate open reduction internal fixation or total Hip arthroplasty. Diagnosis A 70-year-old woman presented to the physical therapy clinic with complaints of right Hip pain. She had been evaluated by a physician and radiographs of the Hip, which revealed some arthritic changes, were otherwise normal. Upon examination, the physical therapist observed an antalgic gait, a noncapsular pattern of limitation of Hip motion, an empty painful end feel at the end range of motion (ROM) for Hip abduction, external rotation, and flexion, and extreme tenderness to palpation over the anterior Hip Region. The therapist suspected a more pernicious problem than osteoarthritis and discussed his suspicion with the ph...

Jan E Gildea - One of the best experts on this subject based on the ideXlab platform.

  • morphology of the abdominal muscles in ballet dancers with and without low back pain a magnetic resonance imaging study
    2014
    Co-Authors: Jan E Gildea, Julie A Hides, Paul W Hodges
    Abstract:

    Abstract Objectives To evaluate the morphology of transversus abdominis and obliquus internus abdominis muscles and the ability to “draw in” the abdominal wall, in professional ballet dancers without low back pain, with low back pain or both Hip Region and low back pain. Design Observational study. Methods Magnetic resonance images of 31 dancers were taken at rest and during voluntary abdominal muscle contraction. Measurements included the thickness of transversus abdominis and obliquus internus abdominis muscles, lateral slide of the anterior extent of the transversus abdominis muscles (transversus abdominis slide) and reduction in total cross sectional area of the trunk. Results The transversus abdominis and obliquus internus abdominis muscles were thicker in male dancers and the right side was thicker than the left in both genders. There was no difference in muscle thickness as a proportion of the total thickness, between dancers with and without pain, although there was a trend for female dancers with low back pain only to have a smaller change in transversus abdominis muscle thickness with contraction than those without pain. Transversus abdominis slide was less in female dancers than in male dancers. When gender was ignored, the extent of transversus abdominis slide was less in dancers with low back pain only. Reduction in trunk cross sectional area with contraction was not different between genders or groups. Conclusions This study provides evidence that the abdominal muscles (transversus abdominis and obliquus internus abdominis) are asymmetrical in dancers and although the abdominal muscles are not different in structure (resting thickness) in dancers with LBP, there is preliminary evidence for the behavioural change of reduced slide of transversus abdominis during the ‘draw in’ of the abdominal wall.

  • size and symmetry of trunk muscles in ballet dancers with and without low back pain
    2013
    Co-Authors: Jan E Gildea, Julie A Hides, Paul W Hodges
    Abstract:

    Study Design Cross-sectional, observational study. Objectives To investigate the cross-sectional area (CSA) of trunk muscles in professional ballet dancers with and without low back pain (LBP). Background LBP is the most prevalent chronic injury in classical ballet dancers. Research on nondancers has found changes in trunk muscle size and symmetry to be associated with LBP. There are no studies that examine these changes in ballet dancers. Methods Magnetic resonance imaging was performed in 14 male and 17 female dancers. The CSAs of 4 muscles (multifidus, lumbar erector spinae, psoas, and quadratus lumborum) were measured and compared among 3 groups of dancers: those without LBP or Hip pain (n = 8), those with LBP only (n = 13), and those with both Hip-Region pain and LBP (n = 10). Results Dancers with no pain had larger multifidus muscles compared to those with LBP at L3–5 (P<.024) and those with both Hip-Region pain and LBP at L3 and L4 on the right side (P<.027). Multifidus CSA was larger on the left s...

Patrick D. Wettenschwiler - One of the best experts on this subject based on the ideXlab platform.

  • validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage
    2017
    Co-Authors: Patrick D. Wettenschwiler, Stephen J. Ferguson, Simon Annaheim, Silvio Lorenzetti, Rolf Stämpfli, Agnes Psikuta, René M. Rossi
    Abstract:

    Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R2>0.5) in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a Hip belt, were assessed. The mechanical parameters were measured in the shoulder and the Hip Region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg), combined with four different Hip belt tensions (30N, 60N, 90N, and 120N). Through the significant (p<0.05) correlation of the mechanical parameters measured on the dummy with the corresponding values of the subject study, the dummy was validated for all static measurements and for dynamic measurements in the Hip Region to accurately simulate the interaction between the human body and the load carriage system. Multiple linear regressions with the mechanical parameters measured on the dummy as independent variables and the corresponding subjective discomfort scores from the subject study as the dependent variable revealed a high predictive power of the instrumented dummy. The dummy can explain 75% or more of the variance in discomfort using average pressures as predictors and even 79% or more of the variance in discomfort using strap forces as predictors. Use of the dummy enables objective, fast, and iterative assessments of load carriage systems and therefore reduces the need for labor-intensive subject studies in order to decrease the mechanical aspects of discomfort during load carriage.

  • Validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage
    2017
    Co-Authors: Patrick D. Wettenschwiler, Stephen J. Ferguson, Simon Annaheim, Silvio Lorenzetti, Rolf Stämpfli, Agnes Psikuta, René M. Rossi
    Abstract:

    Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R2>0.5) in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a Hip belt, were assessed. The mechanical parameters were measured in the shoulder and the Hip Region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg), combined with four different Hip belt tensions (30N, 60N, 90N, and 120N). Through the significant (p