Characteristics and Predictors of Postural Control Impairment in Patients With COPD Participating in a Pulmonary Rehabilitation Program.

PURPOSE: Postural control impairment has been identified as a potential extrarespiratory manifestation in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to identify clinical factors that characterize patients with reduced postural control, to examine the correlation between clinical factors and postural control and to determine predictors of an impaired postural control among COPD participants enrolled in a pulmonary rehabilitation (PR) program. METHODS: This study is a secondary analysis of an observational study (PARACHUTE). The baseline assessment of the PR program was used for the analysis. Postural control impairment was defined using the Brief BESTest score (BBT). RESULTS: Participants (n = 73) were included in the analysis, 43 of them were classified in the reduced postural control group. The between-group comparison (non-reduced vs reduced postural control) identified differences for partial pressure in oxygen (Pa O2 ), Saint George Respiratory Questionnaire (SGRQ) total score and subscores (SGRQ-Symptoms, SGRQ-Activities, and SGRQ-Impact), COPD assessment test (CAT), and anxiety score of the Hospital Anxiety and Depression Scale. The BBT score was significantly correlated with maximal inspiratory pressure (MIP), SGRQ, SGRQ-Symptoms, SGRQ-Impact, Falls Efficacy Scale, modified Medical Research Council Scale, 6-min walk test, and Pa O2 . Logistic regression identified SGRQ-Symptoms, Pa O2 , MIP, and body mass index (BMI) as predictors of the presence of reduced postural control. CONCLUSION: Low quality of life (QoL) and Pa O2 and high anxiety seem to be discriminative characteristics of patients with COPD with reduced postural control. Furthermore, QoL, Pa O2 , inspiratory muscle strength, and BMI seem to be acceptable predictors of the presence of postural control impairment.

Impairment and characteristics of postural control sub-components in people with COPD: a scoping review.

PURPOSE: Impairment of postural control is common in people with COPD. However, the precise characteristics of this alteration are not clearly known. The "Systems Framework for Postural Control" which define postural control sub-components, represents an interesting tool to explore this field. The main aim of this review was to identify which postural control sub-components are impaired in people with COPD and to summarise characteristics for each sub-component. A secondary aim was to precise the relation between postural control and activities of daily living (ADL). MATERIALS AND METHODS: A scoping review was conducted, according to the JBI methodology. Medline, Cochrane Library, Scielo, Google Scholar, OpenGrey, and HAL were searched from inception to May 2022. The search was performed in English and French. RESULTS: Eighty-nine articles were included. There was evidence of a potential impairment for most of the postural control sub-components. Characteristics of every sub-component alteration were heterogeneous. Reduced postural control could be associated with difficulties in ADL. CONCLUSIONS: People with COPD may have impairment in a wide range of postural control sub-components. Further research is needed to clarify if a common pattern of modification exits for this alteration and to precise the link with ADL.Implications for rehabilitationImpairment of postural control is a common extra-respiratory manifestation in people with COPD and so clinicians must include it in their clinical reasoning.Numerous postural control sub-components could be altered in people with COPD, suggesting that postural control assessment must be holistic.This scoping review shows that characteristics of postural control impairment are varied and that there may be no common pattern at the COPD population level.The relationship between impaired postural control and activities of daily living remains unclear, but clinicians should be alert to potential negative interactions between these two areas.

Combining Freehand Ultrasound-Based Indentation and Inverse Finite Element Modeling for the Identification of Hyperelastic Material Properties of Thigh Soft Tissues.

Finite element analysis (FEA) is a numerical modeling tool vastly employed in research facilities to analyze and predict load transmission between the human body and a medical device, such as a prosthesis or an exoskeleton. Yet, the use of finite element modeling (FEM) in a framework compatible with clinical constraints is hindered by, among others, heavy and time-consuming assessments of material properties. Ultrasound (U.S.) imaging opens new and unique opportunities for the assessment of in vivo material properties of soft tissues. Confident of these advances, a method combining a freehand U.S. probe and a force sensor was developed in order to compute the hyperelastic constitutive parameters of the soft tissues of the thigh in both relaxed (R) and contracted (C) muscles' configurations. Seven asymptomatic subjects were included for the experiment. Two operators in each configuration performed the acquisitions. Inverse FEM allowed for the optimization of an Ogden's hyperelastic constitutive model of soft tissues of the thigh in large displacement. The mean shear modulus identified for configurations R and C was, respectively, 3.2 ± 1.3 kPa and 13.7 ± 6.5 kPa. The mean alpha parameter identified for configurations R and C was, respectively, 10 ± 1 and 9 ± 4. An analysis of variance showed that the configuration had an effect on constitutive parameters but not on the operator.

Using Torque-Angle and Torque-Velocity Models to Characterize Elbow Mechanical Function: Modeling and Applied Aspects.

Characterization of muscle mechanism through the torque-angle and torque-velocity relationships is critical for human movement evaluation and simulation. in vivo determination of these relationships through dynamometric measurements and modeling is based on physiological and mathematical aspects. However, no investigation regarding the effects of the mathematical model and the physiological parameters underneath these models was found. The purpose of the current study was to compare the capacity of various torque-angle and torque-velocity models to fit experimental dynamometric measurement of the elbow and provide meaningful mechanical and physiological information. Therefore, varying mathematical function and physiological muscle parameters from the literature were tested. While a quadratic torque-angle model seemed to increase predicted to measured elbow torque fitting, a new power-based torque-velocity parametric model gave meaningful physiological values to interpret with similar fitting results to a classical torque-velocity model. This model is of interest to extract modeling and clinical knowledge characterizing the mechanical behavior of such a joint.

Comparison between line and surface mesh models to represent the rotator cuff muscle geometry in musculoskeletal models.

Accurate muscle geometry (muscle length and moment arm) is required to estimate muscle function when using musculoskeletal modelling. In shoulder, muscles are often modelled as a collection of independent line segments, leading to non-physiological muscles trajectory, especially for the rotator cuff muscles. To prevent this, a surface mesh model was developed and validated against 7 MRI positions in one participant. Mean moment arm errors was 11.4% for the line vs. 8.8% for the mesh model. While the model with independent lines led to some non-physiological trajectories, the mesh model gave lower misestimations of muscle lengths and moment arms.

Identification of the contribution of contact and aerial biomechanical parameters in acrobatic performance.

INTRODUCTION: Teaching acrobatic skills with a minimal amount of repetition is a major challenge for coaches. Biomechanical, statistical or computer simulation tools can help them identify the most determinant factors of performance. Release parameters, change in moment of inertia and segmental momentum transfers were identified in the prediction of acrobatics success. The purpose of the present study was to evaluate the relative contribution of these parameters in performance throughout expertise or optimisation based improvements. The counter movement forward in flight (CMFIF) was chosen for its intrinsic dichotomy between the accessibility of its attempt and complexity of its mastery. METHODS: Three repetitions of the CMFIF performed by eight novice and eight advanced female gymnasts were recorded using a motion capture system. Optimal aerial techniques that maximise rotation potential at regrasp were also computed. A 14-segment-multibody-model defined through the Rigid Body Dynamics Library was used to compute recorded and optimal kinematics, and biomechanical parameters. A stepwise multiple linear regression was used to determine the relative contribution of these parameters in novice recorded, novice optimised, advanced recorded and advanced optimised trials. Finally, fixed effects of expertise and optimisation were tested through a mixed-effects analysis. RESULTS AND DISCUSSION: Variation in release state only contributed to performances in novice recorded trials. Moment of inertia contribution to performance increased from novice recorded, to novice optimised, advanced recorded, and advanced optimised trials. Contribution to performance of momentum transfer to the trunk during the flight prevailed in all recorded trials. Although optimisation decreased transfer contribution, momentum transfer to the arms appeared. CONCLUSION: Findings suggest that novices should be coached on both contact and aerial technique. Inversely, mainly improved aerial technique helped advanced gymnasts increase their performance. For both, reduction of the moment of inertia should be focused on. The method proposed in this article could be generalized to any aerial skill learning investigation.

Mechanical risk of rotator cuff repair failure during passive movements: A simulation-based study.

BACKGROUND: Despite improvements in rotator cuff surgery techniques, re-tear rate remains above 20% and increases with tear severity. Mechanical stresses to failure of repaired tendons have been reported. While optimal immobilization postures were proposed to minimize this stress, post-operative rehabilitation protocols have never been assessed with respect to these values. Purpose was to use musculoskeletal simulation to predict when the stress in repaired tendons exceeds safety limits during passive movements. Hence, guidelines could be provided towards safer post-operative exercises. METHODS: Sixteen healthy participants volunteered in passive three-dimensional shoulder range-of-motion and passive rehabilitation exercises assessment. Stress in all rotator cuff tendons was predicted during each movement by means of a musculoskeletal model using simulations with different type and size of tears. Safety stress thresholds were defined based on repaired tendon loads to failure reported in the literature and used to discriminate safe from unsafe ranges-of-motion. FINDINGS: Increased tear size and multiple tendons tear decreased safe range-of-motion. Mostly, glenohumeral elevations below 38°, above 65°, or performed with the arm held in internal rotation cause excessive stresses in most types and sizes of injury during abduction, scaption or flexion. Larger safe amplitudes of elevation are found in scapular plane for supraspinatus alone, supraspinatus plus infraspinatus, and supraspinatus plus subscapularis tears. INTERPRETATION: This study reinforces that passive early rehabilitation exercises could contribute to re-tear due to excessive stresses. Recommendations arising from this study, for instance to keep the arm externally rotated during elevation in case of supraspinatus or supraspinatus plus infraspinatus tear, could help prevent re-tear.

Local versus global optimal sports techniques in a group of athletes.

Various optimization algorithms have been used to achieve optimal control of sports movements. Nevertheless, no local or global optimization algorithm could be the most effective for solving all optimal control problems. This study aims at comparing local and global optimal solutions in a multistart gradient-based optimization by considering actual repetitive performances of a group of athletes performing a transition move on the uneven bars. Twenty-four trials by eight national-level female gymnasts were recorded using a motion capture system, and then multistart sequential quadratic programming optimizations were performed to obtain global optimal, local optimal and suboptimal solutions. The multistart approach combined with a gradient-based algorithm did not often find the local solution to be the best and proposed several other solutions including global optimal and suboptimal techniques. The qualitative change between actual and optimal techniques provided three directions for training: to increase hip flexion-abduction, to transfer leg and arm angular momentum to the trunk and to straighten hand path to the bar.

Measurement and description of three-dimensional shoulder range of motion with degrees of freedom interactions.

The shoulder is the most mobile joint of the human body due to bony constraint scarcity and soft tissue function unlocking several degrees of freedom (DOF). Clinical evaluation of the shoulder range of motion (RoM) is often limited to a few monoplanar measurements where each DOF varies independently. The main objective of this study was to provide a method and its experimental approach to assess shoulder 3D RoM with DOF interactions. Sixteen participants performed four series of active arm movements with maximal amplitude consisting in (1) elevations with fixed arm axial rotations (elevation series), (2) axial rotations at different elevations (rotation series), both in five planes of elevation, (3) free arm movements with the instruction to fill the largest volume in space while varying hand orientation (random series), and (4) a combination of elevation and rotation series (overall series). A motion analysis system combined with an upper limb kinematic model was used to estimate the 3D joint kinematics. Thoracohumeral Euler angles with correction were chosen to represent rotations. The angle-time-histories were treated altogether to analyze their 3D interaction. Then, all 3D angular poses were included into a nonconvex hull representing the RoM space accounting for DOF interactions. The effect of series of movements (n = 4) on RoM volumes was tested with a one-way repeated-measures ANOVA followed by Bonferroni posthoc analysis. A normalized 3D RoM space was defined by including 3D poses common to a maximal number of participants into a hull of average volume. A significant effect of the series of movements (p < 0.001) on the volumes of thoracohumeral RoM was found. The overall series measured the largest RoM with an average volume of 3.46 ± 0.89 million cubic degrees. The main difference between the series of movements was due to axial rotation. A normalized RoM hull with average volume was found by encompassing arm poses common to more than 50% of the participants. In general, the results confirmed and characterized the complex 3D interaction of shoulder RoM between the DOF. The combination of elevation and rotation series (overall series) is recommended to fully evaluate shoulder RoM. The normalized 3D RoM hull is expected to provide a reliable reference to evaluate shoulder function in clinical research and for defining physiologic continuous limits in 3D shoulder computer simulation models.