Shoulder kinematics and muscle activity following latissimus dorsi transfer for massive irreparable posterosuperior rotator cuff tears in shoulders with pseudoparalysis

Background: The aim of this study was to evaluate the thoracohumeral (TH) and glenohumeral (GH) motion with muscle activity after latissimus dorsi transfer (LDT) in a shoulder with a massive irreparable posterosuperior rotator cuff tear (MIRT) and pseudoparalysis compared with the asymptomatic contralateral shoulder (ACS). Methods: We...

Establishing the Role of Elbow Muscles by Evaluating Muscle Activation and Co-contraction Levels at Maximal External Rotation in Fastball Pitching

Background: Baseball pitching is associated with a high prevalence of ulnar collateral ligament injuries, potentially due to the high external valgus load on the medial side of the elbow at the instant of maximal shoulder external rotation (MER). In-vitro studies show that external valgus torque is resisted by the ulnar collateral ligament but...

Control strategies for active lower extremity prosthetics and orthotics: A review

Technological advancements have led to the development of numerous wearable robotic devices for the physical assistance and restoration of human locomotion. While many challenges remain with respect to the mechanical design of such devices, it is at least equally challenging and important to develop strategies to control them in concert with the...

Glove effects on forearm muscle activity in a windsurfing-like task

Windsurfers currently do not wear neoprene gloves when sailing in cold temperatures, as discomfort rapidly develops in the forearms when doing so. Lack of good protection against low temperatures means the hands get painfully cold and numb, limiting sailing time and pleasure. ElectroMyoGraphy (EMG) measurements were done on four forearm muscles...

Evaluation of EMG, force and joystick as control interfaces for active arm supports

Background: The performance capabilities and limitations of control interfaces for the operation of active movement-assistive devices remain unclear. Selecting an optimal interface for an application requires a thorough understanding of the performance of multiple control interfaces. Methods: In this study the performance of EMG-, force- and...

Neck muscle control patterns in 3D isometric experiments

The better understanding of neuromuscular control of the human neck is of critical importance to understand whiplash injury and neurological movement disorders. Isometric experiments using electromyography (EMG) are an appropriate method to study neuromuscular control patterns of neck muscles. As the human head-neck system is highly complex, it...

Evaluation of EMG, Force and Joystick as Control Interfaces for Active Upper-Extremity Movement-Assistive Devices

Currently, many different control interfaces for the operation of active movement-assistive device exist but their respective performance capabilities and limitations remain unclear. The goal of this study was to quantitatively evaluate the performance and learning characteristics of EMG-, force- and hand joystick-based interfaces. The human...

The gap between clinical gaze and systematic assessment of movement disorders after stroke

Background: Movement disorders after stroke are still captured by clinical gaze and translated to ordinal scores of low resolution. There is a clear need for objective quantification, with outcome measures related to pathophysiological background. Neural and non-neural contributors to joint behavior should be separated using different...

EMG feedback tasks reduce reflexive stiffness during force and position perturbations

Force and position perturbations are widely applied to identify muscular and reflexive contributions to posture maintenance of the arm. Both task instruction (force vs. position) and the inherently linked perturbation type (i.e., force perturbations-position task and position perturbations-force tasks) affect these contributions and their mutual...

Quantifying Proprioceptive Reflexes During Position Control of the Human Arm

This study aimed to analyse the dynamic properties of the muscle spindle feedback system of shoulder muscles during a posture task. External continuous force disturbances were applied at the hand while subjects had to minimize their hand displacements. The results were analysed using two frequency response functions (FRFs) from which the model...