Adaptive Control of Exoskeleton Robots for Periodic Assistive Behaviours Based on EMG Feedback Minimisation.

In this paper we propose an exoskeleton control method for adaptive learning of assistive joint torque profiles in periodic tasks. We use human muscle activity as feedback to adapt the assistive joint torque behaviour in a way that the muscle activity is minimised. The user can then relax while the exoskeleton takes over the task execution. If the task is altered and the existing assistive behaviour becomes inadequate, the exoskeleton gradually adapts to the new task execution so that the increased muscle activity caused by the new desired task can be reduced. The advantage of the proposed method is that it does not require biomechanical or dynamical models. Our proposed learning system uses Dynamical Movement Primitives (DMPs) as a trajectory generator and parameters of DMPs are modulated using Locally Weighted Regression. Then, the learning system is combined with adaptive oscillators that determine the phase and frequency of motion according to measured Electromyography (EMG) signals. We tested the method with real robot experiments where subjects wearing an elbow exoskeleton had to move an object of an unknown mass according to a predefined reference motion. We further evaluated the proposed approach on a whole-arm exoskeleton to show that it is able to adaptively derive assistive torques even for multiple-joint motion.

[Anatomical basis and clinical application of "two points" acupotomology surgery program in treating cubital tunnel syndrome].

OBJECTIVE: To explore an effective acupotomology surgery program in treating cubital tunnel syndrome. METHODS: According to pathogenic factors and elbow anatomy, a "two points" acupotomology surgery program was designed, which could loose the attachment point of arcuate ligament on medial border of olecroanon and medial epicondyle of humerus. Twenty-one cases of cubital tunnel syndrome were treated with acupotmology, then the efficacy was obsered. RESULTS: After one year postoperative visit, 21 patients with ulnar nerve area skin numbness were cured, claw hand deformity and medial hand muscle atrophy recovered significantly. Results of function evaluation were excellent in 17 cases, good in 2 cases, fair in 2 cases and poor in 0 cases, the good rate was 90.5%. CONCLUSION: The acupotomology surgery program which could cut the starting and ending points of osborne's ligament and solve the problem of ulnar nerve entrapment is an easy, little-traumatic and effective minimally invasive surgery which also conforms to the anatomical structure.

Anatomical association between wrist extensor musculature and topographical pain sensitivity maps of the elbow area.

OBJECTIVE: High-density topographical sensitivity maps have been developed to visualize nonuniformity deep tissue pain sensitivity in, for example, lateral epicondylitis (LE). The aim of this cadaveric study was to determine the anatomical association between the topographical sensitivity maps over the elbow area and wrist extensor musculature. METHODS: A topographical pressure sensitivity map consisting of 12 points forming a 3 × 4 matrix: 4 points in the superior part, 4 points in the middle, and 4 points in the lower part around the lateral epicondyle was marker on a 50-year embalmed cadaver. Color marker pins were inserted into each point. Pins were removed during the process of dissection, but the small holes created by their removal assured accurate relocation. RESULTS: Progressive dissection revealed that points 1 to 4 (superior line) were placed over the musculotendinous junction and belly of the extensor carpi radialis brevis (ECRB) muscle, points 6 to 8 (middle line) were placed over the musculotendinous junction and belly of the extensor digitorum communis muscle, and points 9 to 12 (inferior line) were located over the musculotendinous junction and belly of the extensor carpi ulnaris muscle. It was also observed that the superficial branch of the radial nerve runs between the belly of the ECRB and extensor digitorum communis muscles. CONCLUSIONS: This study confirmed that anatomical location previously assumed supporting the important wrist extensor muscles, particularly the ECRB, in patients with LE as depicted by pressure pain sensitivity maps. This study also suggests a potential role of the superficial branch of the radial nerve in LE.

Procedure-oriented sectional anatomy of the elbow.

This is the second in a series of papers related to procedure-oriented joint anatomy. This article will review the anatomy of the elbow and its relationship to procedures in the clinical setting. Needle procedures of the elbow joint include medial and lateral epicondyle injections, olecranon bursa injection, elbow joint aspiration, phlebotomies in the antecubital fossa, and intramuscular injections such as trigger point and botulinum toxin injections. Complications related to these procedures include infection, skin atrophy, injuries to peripheral nerves, tendon rupture associated with the use of corticosteroids, iatrogenic vascular injuries, and chronic local pain. This article provides anatomically accurate schematics of the elbow anatomy relevant to needle procedures. Cross-sectional anatomical schematics of the elbow were drawn as they appear on axial and coronal projections. Superficial and deep landmarks are highlighted as well as sources of potential complications. These schematics allow for safer and more accurate needle procedures in the elbow area, for both nonguided and musculoskeletal ultrasound-guided techniques.

The effects of training set on prediction of elbow trajectory from shoulder trajectory during reaching to targets.

Patients with transhumeral amputations and C5/C6 quadriplegia may be able to use voluntary shoulder motion as command signals for powered prostheses and functional electrical stimulation, respectively. Spatio-temporal synergies exist for goal oriented reaching movements between the shoulder and elbow joints in able bodied subjects. We are using a multi-layer perceptron neural network to discover and embody these synergies. Such a network could be used as a high level functional electrical stimulation (FES) controller that could predict elbow joint kinematics from the voluntary movements of the shoulder joint. Counter-intuitively, a well-chosen reduced data set for training the network resulted in better performance than use of the whole data set against which the predictions of the network were evaluated.

Body composition and isokinetic strength of professional Sumo wrestlers.

The purpose of this study was to investigate the profiles of body composition and force generation capability in professional Sumo wrestlers. The subjects were 23 professional Sumo wrestlers [mean age 22.0 (SEM 1.2) years] including those ranked in the lower- (Jonokuchi, n=10), middle- (Sandanme, n=8) and higher-division (Makuuchi, n=5), 22 weight-classified athletes [5 judo athletes, 5 wrestlers, and 12 weight lifters, mean age 20.7 (SEM 0.7) years], and 21 untrained men [mean age 20.1 (SEM 0.2) years]. In the Sumo wrestlers, body mass ranged between 77.0 and 150.0 kg, body mass index between 25.9 and 44.5 kg x m(-2), relative fat mass (%FM) between 11.9 and 37.0%, and fat-free mass (FFM) between 59.1 and 107.6 kg. The Sumo wrestlers showed significantly higher %FM and smaller elbow and knee extensor cross-sectional areas (CSA) than the weight-classified athletes who weighed from 90.4 kg to 133.2 kg. Moreover, isokinetic forces in the flexion and extension of elbow and knee joints, respectively, at three constant velocities of 1.05, 3.14 and 5.24 rad x s(-1) were significantly lower in the Sumo wrestlers than in the weight-classified athletes and untrained subjects when expressed per unit of body mass. However, the median value of FFM relative to body height in the higher-division Sumo wrestlers was ranked high in the range of magnitude among those reported previously in the literature for heavyweight athletes. Moreover, the results on the comparisons within the Sumo wrestlers showed that not only FFM but also force generation capability, expressed both as an absolute term and as a value relative to both body mass and muscle CSA, might be factors contributing to the performance of Sumo wrestlers.

A martial arts exploration of elbow anatomy: Ikkyo (Aikido's first teaching).

The Martial Art of Aikido, based on several effective anatomical principles, is used to subdue a training partner. One of these methods is Ikkyo (First Teaching). According to Saotome, the original intent of Ikkyo was to "break the elbow joint" of an enemy. Nowadays the intent is to secure or pin a training partner to the mat. This investigation focused on examining Ikkyo with the purpose of describing the nerves, bones, and muscles involved in receiving this technique. Particular focus was placed on the locations and sources of the reported pain.