1,008 research outputs found

    The Effect of Exercise, Prewrap, and Athletic Tape on the Maximal Active and Passive Ankle Resistance to Ankle Inversion

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    This investigation explored alternatives to the null hy potheses that maximal active and passive resistance to inversion developed by a near-maximally inverted and weightbearing ankle is not altered by 1) the use of prophylactic adhesive athletic tape, 2) the use of non- adhesive prewrap (underwrap), or 3) 40 minutes of vigorous exercise. Ten healthy men and 10 healthy women (mean age, 25 ¹ 3 years) with no recent ankle injuries underwent testing to determine maximal ankle resistance to inversion under unipedal, weightbearing conditions. Tests were performed with and without the support of athletic tape, and before and after 40 min utes of exercise. Half the testing sessions were per formed with prewrap under the tape. At 15° of inver sion, without any external ankle support, healthy young men and women could maximally resist a mean (SD) inversion moment of 52.9 (6.4) N-m and 28.3 (5.8) N-m, respectively. Although use of ankle tape provided a 10% increase in maximal resistance to inversion moments, this increase diminished to insignificant lev els after 40 minutes of vigorous exercise. Use of pre wrap improved maximal resistance to inversion by more than 10%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66568/2/10.1177_036354659702500203.pd

    New perspectives on ACL injury: On the role of repetitive subâ maximal knee loading in causing ACL fatigue failure

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    In this paper, we review a series of studies that we initiated to examine mechanisms of anterior cruciate ligament (ACL) injury in the hope that these injuries, and their sequelae, can be better prevented. First, using the earliest in vitro model of a simulated singleâ leg jump landing or pivot cut with realistic knee loading rates and transâ knee muscle forces, we identified the worstâ case dynamic knee loading that causes the greatest peak ACL strain: Combined knee compression, flexion, and internal tibial rotation. We also identified morphologic factors that help explain individual susceptibility to ACL injury. Second, using the above knee loading, we introduced a possible paradigm shift in ACL research by demonstrating that the human ACL can fail by a sudden rupture in response to repeated subâ maximal knee loading. If that load is repeated often enough over a short time interval, the failure tended to occur proximally, as observed clinically. Third, we emphasize the value of a physical exam of the hip by demonstrating how limited internal axial rotation at the hip both increases the susceptibility to ACL injury in professional athletes, and also increases peak ACL strain during simulated pivot landings, thereby further increasing the risk of ACL fatigue failure. When training atâ risk athletes, particularly females with their smaller ACL crossâ sections, rationing the number and intensity of worstâ case knee loading cycles, such that ligament degradation is within the ACL’s ability to remodel, should decrease the risk for ACL rupture due to ligament fatigue failure.© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2059â 2068, 2016.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135588/1/jor23441.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135588/2/jor23441_am.pd

    Poster 194: Biomechanical Analysis of a Novel Clinical Measure of Reaction Time

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147091/1/pmr2s188a.pd

    Association of index finger palpatory assessment of pubovisceral muscle body integrity with MRIâ documented tear

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    AimsPubovisceral (PV) muscle tears are associated with pelvic floor disorders. The goal of this study was to determine whether index finger palpatory assessment of PV muscle body integrity through the lateral vaginal wall is a reliable indicator of PV muscle tear severity diagnosed by magnetic resonance imaging (MRI).MethodsWe studied 85 women, 7 weeks after vaginal birth. All had at least one risk factor for obstetricâ related PV muscle tear. The ordinal outcome measure of MRIâ documented PV muscle tear was defined as: none, less than 50% unilateral tear, 50% or greater unilateral tear or less than 50% bilateral tear, and 50% or greater bilateral tear. PV muscle body integrity by palpatory assessment was scored on a matrix, with each side scored independently and classified as PV muscle body â presentâ (assuredly felt), â equivocalâ (not sure if felt), or â absentâ (assuredly not felt). Proportional odds models were constructed to estimate the relationship between PV muscle body integrity palpatory assessment and MRIâ documented PV muscle tears.ResultsThirtyâ five percent of study participants exhibited varying degrees of MRIâ documented PV muscle tears. Using palpatory assessment, we identified â PV muscle body present bilaterallyâ in 20%, â equivocal unilaterally or present contralaterallyâ in 8%, â equivocal or absent unilaterallyâ or â equivocal bilaterallyâ in 62%, and â absent bilaterallyâ in 9%. The odds ratio for estimating MRI results from palpatory assessment was 3.62 (95% confidence intervalâ =â 1.70â 7.73, Pâ =â 0.001).ConclusionsA rapid and inexpensive palpatory assessment in the clinic was highly associated with the risk of MRIâ documented PV muscle tear and is a useful component of a clinical assessment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149233/1/nau23967_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149233/2/nau23967.pd

    Mechanisms of continence and surgical cure in female and male SUI: Surgical research initiatives

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    Aims To report the conclusions of the Think Tank on mechanisms of incontinence and surgical cure in female and male SUI: surgical research initiatives during the ICI‐RS meeting in 2010. Methods The sub‐group considered five areas for future research in stress urinary incontinence (SUI); (i) epidemiology and public health efforts in SUI, (ii) the basic sciences examining the physiology and pathophysiology of the continence mechanism, (iii) diagnostic techniques and clinical assessment of SUI, (iv) the future of treatment and surgical cure, and (v) the separate issue of male SUI. Results Roadblocks to progress were identified for each of the five directions. Conclusions Future research directions are suggested for each of these areas. Neurourol. Urodynam. 30:704–707, 2011. © 2011 Wiley‐Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87181/1/21139_ftp.pd

    Convolutional neural network- based pelvic floor structure segmentation using magnetic resonance imaging in pelvic organ prolapse

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162690/2/mp14377.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162690/1/mp14377_am.pd

    Stepping Responses of Young and Old Adults to Postural Disturbances: Kinematics

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111171/1/j.1532-5415.1994.tb04972.x.pd

    Effect of increased quadriceps tensile stiffness on peak anterior cruciate ligament strain during a simulated pivot landing

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    ACL injury prevention programs often involve strengthening the knee muscles. We posit that an unrecognized benefit of such training is the associated increase in the tensile stiffness of the hypertrophied muscle. We tested the hypothesis that an increased quadriceps tensile stiffness would reduce peak anteromedial bundle (AM‐)ACL relative strain in female knees. Twelve female cadaver knees were subjected to compound impulsive two‐times body weight loads in compression, flexion, and internal tibial torque beginning at 15° flexion. Knees were equipped with modifiable custom springs to represent the nonlinear rapid stretch behavior of a normal and increased stiffness female quadriceps (i.e., 33% greater stiffness). Peak AM‐ACL relative strain was measured using an in situ transducer while muscle forces and tibiofemoral kinematics and kinetics were recorded. A 3D ADAMS™ dynamic biomechanical knee model was used in silico to interpret the experimental results which were analyzed using a repeated‐measures Wilcoxon test. Female knees exhibited a 16% reduction in peak AM‐ACL relative strain and 21% reduction in change in flexion when quadriceps tensile stiffness was increased by 33% (mean (SD) difference: 0.97% (0.65%), p  = 0.003). We conclude that increased quadriceps tensile stiffness reduces peak ACL strain during a controlled study simulating a pivot landing. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:423–430, 2014.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102663/1/jor22531.pd

    A comparison of the effect of age on levator ani and obturator internus muscle cross‐sectional areas and volumes in nulliparous women

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    Aims Functional tests have demonstrated minimal loss of vaginal closure force with age. So we tested the null hypotheses that age neither affects the maximum cross‐sectional area (CSA) nor the volume of the levator muscle. Corresponding hypotheses were also tested in the adjacent obturator internus muscle, which served as a control for the effect of age on appendicular muscle in these women. Methods Magnetic resonance images of 15 healthy younger (aged 21–25 years) and 12 healthy older nulliparous women (aged >63 years) were selected to avoid the confounding effect of childbirth. Models were created from tracing outlines of the levator ani muscle in the coronal plane, and obturator internus in the axial plane using 3D Slicer v. 3.4. Muscle volumes were calculated using Slicer, while CSA was measured using Imageware™ at nine locations. The hypotheses were tested using repeated measures analysis of variance with P  < 0.05 being considered significant. Results The effect of age did not reach statistical significance for the decrease in levator ani muscle maximum CSA or the decrease in volume (4.3%, P  = 0.62 and 10.9%, 0.12, respectively). However, age did significantly adversely decrease obturator internus muscle maximum CSA and volume (24.5% and 28.2%, P  < 0.001, respectively). Significant local age‐related changes were observed dorsally in both muscles. Conclusions Unlike the adjacent appendicular muscle, obturator internus, the levator ani muscle in healthy nullipara does not show evidence of significant age‐related atrophy. Neurourol. Urodynam. 31:481–486, 2012. © 2012 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91125/1/21208_ftp.pd
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