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Postural control is influenced by cognition. In most studies, variability of motor output has been considered regardless of variability in patterns of joint coordination. Uncontrolled manifold framework has been applied to decompose the joint's variance in two components. The first component leaves position of the center of mass in anterior-posterior direction (CoMAP) unchanged (VUCM) while the second component is in charge of variations of CoM (VORT). In this study, 30 healthy young volunteers were recruited. The experimental protocol consisted of three random conditions: quiet standing on a narrow wooden block without a cognitive task (NB), quiet standing on a narrow wooden block with an easy cognitive task (NBE), and quiet standing on a narrow wooden block with a difficult cognitive task (NBD). Results showed that CoMAP sway in NB condition was higher than both NBE and NBD conditions (p =.001). VORT in NB condition was higher than NBE and NBD conditions (p =.003). VORT in NB condition was higher than NBE and NBD conditions (p =.003). VUCM was unchanged in all conditions (p = 1.00) and synergy index in NB condition was smaller than NBE and NBD conditions (p =.006). These results showed that postural synergies increased under dual-task conditions. [ABSTRACT FROM AUTHOR]

Paddler ability in kayaking is reflected through boat motion. Through the application of accelerometers, an easy to use and readily available assessment tool, the current study attempts to determine whether skill level can be ascertained through such measures in order to better assess performance and training. In all, 79 male canoe sprint kayakers participated in this study and paddled a 200 m straight course. According to the time they finished the course, they were divided into three skill level groups and labelled as slow, moderate, and fast speed. Tri-axial boat acceleration data were recorded using an accelerometer system mounted on the back of the kayak. The maximum and standard deviation of boat acceleration along superoinferior, mediolateral, and anteroposterior axes were compared among the three groups. Mixed analysis of variance (ANOVA) test revealed that maximum and standard deviation of acceleration data along the superoinferior axis were significantly greater in the fast speed group than in the moderate and slow ones, and higher in the moderate group than in slow one. These findings suggest that the kayaker's body movements will eventually be reflected in the boat's total acceleration, which could be a measure of overall performance. Given that accelerometers are a small, portable, and easy-to-use devices, and that the results of this study also revealed that boat acceleration differs between different skill groups, it appears that studying acceleration time series in real competition and outside of laboratory environments could open a new window into kayak research. [ABSTRACT FROM AUTHOR]

Context: Clinical evaluation of the spine is commonplace in musculoskeletal therapies, such as physiotherapy, physical medicine/rehabilitation, osteopathic, and chiropractic clinics. Sit-to-stand (STS) is one of the most mechanically demanding daily activities and crucial to independence. Difficulty or inability to perform STS is common in individuals with a variety of motor disabilities, such as low back pain (LBP). Objective: The purpose of this systematic review was to evaluate available evidence in literature to determine 2-dimensional and 3-dimensional kinematics of the spine during STS in patients with LBP and healthy young adult participants using motion analysis systems (electromagnetic and marker based). Methods: Electronic databases (PubMed/MEDLINE [National Library of Medicine], Scopus, ScienceDirect, and Google Scholar) were searched between January 2002 and February 2017. Additionally, the reference lists of the articles that met the inclusion criteria were also searched. Prospective studies published in peer-reviewed journals, with full text available in English, investigating the kinematics of the spine during STS in healthy subjects (mean age between 18 and 50 y) or in patients with LBP using motion analysis systems, were included. Sixteen studies fulfilled the eligibility criteria. All information relating to methodology and kinematic modeling of the spine segments along with the outcome measures was extracted from the studies identified for synthesis. Results: The results indicated that the kinematics of the spine are greatly changed in patients with LBP. In order to develop a better understanding of spine kinematics, studies recommended that the trunk should be analyzed as a multisegment. It has been shown that there is no difference between the kinematics of patients with LBP and healthy population when the spine is analyzed as a single segment. Furthermore, between-gender differences are present during STS movement. Conclusion: This review provided a valuable summary of the research to date examining the kinematics of the spine during STS. [ABSTRACT FROM AUTHOR]

Background: It has been demonstrated that pelvic floor muscles (PFMs) are involved in the pathophysiology of stress urinary incontinence (SUI). Sense of force, an aspect of proprioception, has never been evaluated in PFMs. Objectives: This study aimed to assess the proprioception of PFMs by evaluating the accuracy of force sense in adult women with SUI compared to those with continence. A further aim was to study the accuracy of force sense between various lengths and tensions of PFMs. Methods: Twenty-three women with SUI and 18 women without it were recruited in six trials with four different test conditions: 5 mm/40% (speculum opening/maximum voluntary contraction (MVC) percentage to produce), 5 mm/70%, 10 mm/40%, and 10 mm/70%. All participants were asked to reproduce the target force based on their own perceptions. The dynamometer was used to evaluate the sense of force. Results: The accuracy of force sense differed between women with SUI and those without it. In all test conditions, women with SUI had higher force reproduction accuracy. The highest amount of error was recorded at 10mmand 40% MVC for either group. Conclusions: Women with SUI were more accurate in reproducing the target force than those with continence. Higher force sense accuracy may result from more attention to the pelvic floor area and a lack of automaticity of movements in women with SUI. Therefore, developing therapeutic management focusing on restoring automaticity seems advisable. [ABSTRACT FROM AUTHOR]

Context: Kinesio tape (KT) is a widely used intervention in the fields of sports and rehabilitation. However, its effects on lower-extremity behavior during functional activities are not entirely known. Objective: To test the hypothesis that application of KT can change performance and vertical stiffness (VS) during the countermovement jump (CMJ) before and after a fatigue protocol. Design: A predesign and postdesign to study the effect of KT in 2 situations, prefatigue and postfatigue. In each fatiguing condition, there were 2 conditions with and without KT application on the gastrocnemius muscle. Setting: Biomechanics laboratory. Participants: Fifty healthy, nonathlete participants (26 females and 24 males). Interventions: KT application on the gastrocnemius muscle and a fatigue protocol to induce fatigue in plantar flexor muscles. Main Outcome Measures: Various jumping parameters, including jump height, maximum force, maximum power, rate of force development, eccentric lower-limb stiffness, and VS, were calculated using the vertical ground reaction force data. Eccentric lower-limb stiffness and VS were calculated using a mass-spring model. The studied variables can present lower-extremity elastic behavior and performance during CMJ. Results: The results of a 2-way repeated-measures analysis of variance showed no significant effect for KT application. Fatigue resulted in lower values of jump height, maximum power, and VS. Moreover, male subjects showed greater values of jump height, maximum force, and maximum power than did females. Conclusions: The main finding of this study was that gastrocnemius KT has no effect on performance or elastic behavior of the lower-extremity during CMJ. Moreover, KT cannot reduce the adverse effect of fatigue in a functional activity such as CMJ. It seems that gastrocnemius KT is not effective for demanding activities. [ABSTRACT FROM AUTHOR]

The effect of muscular fatigue on temporal and spectral features of muscle activities and motor performance, i.e., kinematics and kinetics, has been studied. It is of value to quantify fatigue related kinematic changes in biomechanics and sport sciences using simple measurements of joint angles. In this work, a new approach was introduced to extract kinematic changes from 2D phase portraits to study the fatigue adaptation patterns of subjects performing elbow repetitive movement. This new methodology was used to test the effect of load and repetition rate on the temporal changes of an elbow phase portrait during a dynamic iso-inertial fatiguing task. The local flow variation concept, which quantifies the trajectory shifts in the state space, was used to track the kinematic changes of an elbow repetitive fatiguing task in four conditions (two loads and two repetition rates). Temporal kinematic changes due to muscular fatigue were measured as regional curves for various regions of the phase portrait and were also expressed as a single curve to describe the total drift behavior of trajectories due to fatigue. Finally, the effect of load and repetition rate on the complexity of kinematic changes, measured by permutation entropy, was tested using analysis of variance with repeated measure design. Statistical analysis showed that kinematic changes fluctuated more (showed more complexity) under higher loads (p = 0.014), but did not differ under high and low repetition rates (p = 0.583). Using the proposed method, new features for complexity of kinematic changes could be obtained from phase portraits. The local changes of trajectories in epochs of time reflected the temporal kinematic changes in various regions of the phase portrait, which can be used for qualitative and quantitative assessment of fatigue adaptation of subjects and evaluation of the influence of task conditions (e.g., load and repetition rate) on kinematic changes. [DOI: 10.1115/1.4002373] Keywords: kinematic complexity, muscular fatigue, nonlinear dynamics, permutation entropy, elbow joint

Introduction: This study examined the effectiveness of occupational performance coaching, which was delivered through telerehabilitation, in improving children with autism spectrum disorders (ASD) occupational performance, behavior problems, and prosocial behavior in addition to parental self-efficacy and quality of life. Method: Forty-three children were matched and randomized to occupational performance coaching or waitlist groups. Occupational performance, parental self-efficacy, behavioral problems, and prosocial behaviors were assessed using the Canadian Occupational Performance Measure, Child adjustment and parent efficacy scale-developmental disability (CAPES-DD), the Short-Form Health Survey, and goal attainment scale. Results: The intervention group showed greater improvement on occupational performance, specified goals, and behavioral problems. No progress was seen on the CAPES-DD prosocial behavior subscale. In addition, parental quality of life improvement was not maintained after the follow-up phase. Conclusion: Occupation performance coaching, which was delivered through telerehabilitation, was effective on children with ASD occupational performance and parental self-efficacy, but it was not effective on the prosocial behaviors of these children. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to employ nonlinear dynamic approaches to assess trunk dynamic stability with speed, symmetry, and load during repetitive flexion-extension (FE) movements for individuals with and without nonspecific low back pain (NSLBP). Background: Repetitive trunk FE movement is a typical work-related LBP risk factor contingent on speed, symmetry, and load. Improper settings/adjustments of these control parameters could undermine the dynamic stability of the trunk, hence leading to low back injuries. The underlying stability mechanisms and associated control impairments during such dynamic movements remain elusive. Method: Thirty-eight male volunteers (19 healthy, 19 NSLBP) enrolled in the current study. All participants performed repetitive trunk FE movements at high/low speeds, in symmetric/asymmetric directions, with/without a wearable loaded vest. Trunk instantaneous rotation angle was computed for each trial to be assessed in terms of local and orbital stability, using maximum finite-time Lyapunov exponents (LyEs) and Floquet multipliers (FMs), respectively. Results: Both groups demonstrated equivalent competency in terms of trunk control and stability, suggesting functional adaptation strategies may be used by the NSLBP group. Wearing the loaded vest magnified the effects of trunk control impairment for the NSLBP group. The combined presence of high-speed and symmetrical FE movements was associated with least trunk local stability. Conclusion: Nonlinear dynamic techniques, particularly LyE, are potentially effective for assessing trunk dynamic stability dysfunction for individuals with NSLBP during various activities. Application: This work can be applied toward the development of quantitative personalized spinal evaluation tools with a wide range of potential occupational and clinical applications. [ABSTRACT FROM AUTHOR]