Slow Flexion Research Articles

Effects of Different Taping Pressures with Wrist Taping on Isokinetic Strength Exertion of Wrist Dorsal and Palmar Flexion

We aimed to examine the effects of wrist taping at different pressure levels on isokinetic strength exertion of dorsal and palmar flexion. Nineteen healthy male university students were enrolled. The wrist-taping method involved winding a rigid tape around wrist joint thrice. A qualified athletic trainer adjusted taping pressures using a pressure measuring system, whose sensor was on the palmaris longus muscle tendon of the dominant wrist. Isokinetic dorsal and palmar flexion strength was measured by an isokinetic dynamometer system. Taping pressure [5, 30, 60, and 90 hPa and control (no tape)] and angular velocity [slow (60°/sec), moderate (180°/sec), and fast (300°/sec)] were considered independent variables. Peak torque (Nm) of isokinetic strength exertion was considered the dependent variable. Two-way repeated measures analysis of variance (taping pressure × angular velocity) was used to calculate the mean differences for peak torque conditions. A significant difference was found only in the main effect of angular velocity. Multiple comparison tests showed that the isokinetic strength exertion was largest in fast flexion in all taping pressure conditions for dorsal flexion, whereas it was largestin slow flexion in the control and 5-hPa conditions for palmar flexion. For palmar flexion, it was larger in slow flexion for 30-hPa. The effects of taping pressure and flexion speed on isokinetic strength exertion may differ between dorsal and palmar flexion of the same wrist.

Abnormal movements in sleep as a post-polio sequelae.

Nearly two-thirds of polio survivors report abnormal movements in sleep, with 52% reporting that their sleep is disturbed by these movements. Sleep studies were performed in seven polio survivors to document objectively abnormal movements in sleep. Two patients demonstrated generalized random myoclonus, with brief contractions and even ballistic movements of the arms and legs, slow repeated grasping movements of the hands, slow flexion of the arms, and contraction of the shoulder and pectoral muscles. Two other patients demonstrated periodic movements in sleep with muscle contractions and ballistic movements of the legs, two had periodic movements in sleep plus restless legs syndrome, and one had sleep starts involving only contraction of the arm muscles. Abnormal movements in sleep occurred in Stage II sleep in all patients, in Stage I in some patients, and could significantly disturb sleep architecture even though patients were totally unaware of muscle contractions. Poliovirus-induced damage to the spinal cord and brain is presented as a possible cause of abnormal movements in sleep. The diagnosis of post-polio fatigue, evaluation of abnormal movements in sleep, and management of abnormal movements in sleep using benzodiazepines or dopamimetic agents are described.

Muscle sounds in Parkinson's disease

A sound with a frequency of around 40 Hz can be heard, with a stethoscope, in the muscles of the hand and forearm during tonic contraction or movement. This sound is the acoustic correlate of the Piper rhythm seen in electromyographic records of muscle activity. The way in which motor activity is organised at the cortical level may determine the frequency of the sound heard. The wrist extensor muscles in the forearm of seven patients with idiopathic Parkinson's disease, studied with and without antiparkinsonian treatment, and a control group of seven healthy men were auscultated during very strong extension of the wrist and during repeated slow flexion and extension of this joint. In healthy people, the Piper-band sound made by muscle activity is 40-50 Hz. In all seven parkinsonian patients, when off medication, the normal Piper-band sound was replaced by a pulsatile muscle activity of 10 Hz during strong wrist extension, and in four patients during repeated flexion and extension of the wrist. After treatment with dopaminergic drugs, the Piper mode of muscle discharge was restored and motor performance was improved. The Piper mode of muscle discharge is dependent on the normal functioning of pallidal projections to the motor areas of the cortex. In abnormal function a muscle discharge of 10 Hz dominates, which is suboptimal when fast or powerful contractions are necessary.

Cat Distal Forelimb Joints and Locomotion: An X-ray Study.

The complex construction of the joint apparatus of the cat distal forelimb, which allows the paw three degrees of freedom, poses special requirements on the neural signals controlling the paw position. To understand the electromyography (emg) signals of the distal forelimb muscles during locomotion, it is necessary to know the kinematics of the forelimb joints in detail. As no such information is available, we used the pulsed X-ray technique in trained cats during treadmill locomotion to analyse the angular excursions of the wrist, the metacarpophalangeal (MCP) and the proximal interphalangeal (PIP) joints. X-ray illuminations were done in either the parasagittal or the frontal plane. At the beginning of the stance phase the wrist (WR) and the MCP joints extended slowly, and the PIP joints flexed. Whereas the WR and the PIP joints maintained a constant angular position of approximately 200 degrees and 60 degrees, respectively, throughout the stance phase, extension continued in the MCP joints from 240 degrees at touch-down to 300 degrees at the end of the stance phase. Slightly before lift-off (100 ms) the WR and the MCP joints flexed rapidly. This flexion changed approximately 150 ms after lift-off into a slow extension. The PIP joints extended rapidly at the beginning and at the end of the swing phase, during the interposed period of the swing phase they displayed a slow flexion. Rotatory movements of the forelimb in the radioulnar joints were present during the swing and stance phases. During the swing phase the limb first supinated (starting 100 ms after lift-off); pronation occurred immediately before ground contact. During the stance phase the supination angle was kept constant until 100 ms before lift-off, when a short pronation was found. The paw was kept in an ulnar deviated position throughout the complete step cycle. Ulnar deviation decreased at the end of the swing and stance phases. The results of this study increase our understanding of how the body weight is transmitted on to the ground. They suggest four main functions for the skeletomotor apparatus and the underlying neural commands to secure the forward movement of the animal during the stance phase: (i) preparation and stabilization of a force-transmitting platform; (ii) stabilization of the wrist and the carpal/metacarpal joints; (iii) stabilization of the supination angle; (iv) antigravity control of the extension in the MCP.

Short Communication: Distribution of Ion Channels in the Membrane of the DinoflagellateNoctiluca Miliaris

ABSTRACTNoctiluca miliaris, a marine dinoflagellate, exhibits spontaneous flexion of its tentacle. The movement of the tentacle is always accompanied by perturbations of membrane potential, termed the ‘tentacle regulating potentials’ (TRPs) (Eckert and Sibaoka, 1967). Though the waveform of the TRPs is liable to variation, it consists of four successive basic components: (1) a Na+-dependent depolarizing (positive) spike, (2) a depolarizing plateau potential, (3) a Cl−-dependent hyperpolarizing (negative) spike, and (4) a long-lasting hyperpolarization (Eckert and Sibaoka, 1967; Oami et al. 1988). A slow flexion of the tentacle is seen during the plateau, and the flexion is suddenly accelerated when the negative spike occurs. The tentacle then extends during the long-lasting hyperpolarization. There is no correlation between the positive spike and the tentacular movement (Hisada, 1957; Oami et al. 1988).

The Tentacle Cilia of Aglantha digitale (Hydrozoa: Trachylina) and their Control

AbstractThe tentacles of Aglantha have ciliary bands along the sides. Metachronal waves pass along these bands. The strong ciliary currents produced propel water past the tentacles, increasing the probability of prey capture. The ciliated cells are unusual in having many (up to about 500) cilia per cell, where most cnidarian ciliated cells have only one. The cells are also peculiar in containing numerous axonemes without membrane coverings, lying loose in the cytoplasm.Tentacles show independent, rhythmic, slow flexions in the oral direction and groups of tentacles show coordinated, slow flexions as part of a regularly repeated fishing cycle. In both cases, these slow, graded movements are mediated by a slowly conducting system, probably the network of small neurons present in the ectoderm, and are accompanied by ciliary arrests. Much faster, more powerful, coordinated contractions of the tentacles occur in the context of escape behaviour; these are mediated by giant axons which run down the tentacles and are also accompanied by ciliary arrest. Ciliary and muscle effectors evidently share a common motor innervation. Electron microscopy shows that the giant and non‐giant nerves both synapse with muscle cells. The latter are joined to the ciliated cells by gap junctions, and it is suggested that whenever the muscles are excited depolarizations spread to the ciliated cells through the gap junctions and cause ciliary arrests. Neuronal control of ciliary activity has not previously been reported in the Hydrozoa.

Motor control of voluntary trunk movements in standing.

The pattern of activity in different trunk muscles during voluntary trunk movements was studied in the standing position in man. The electromyographic activity from ventral and dorsal trunk muscles on the left and right sides were recorded together with the movements in the sagittal and frontal planes (Selspot optoelectronic system). Movement direction, amplitude, velocity and initial posture were varied. In all movements there was a basic pattern of alternation between antagonist muscle groups. Fast movements were initiated by a sharp burst of activity, whereas slow flexions and side bendings resulted from a decrease in antigravity muscle activity. Movement amplitude was related to the magnitude of the initiating burst, and also to the time of onset of antagonist muscle activity with a braking effect. The contribution of passive internal forces in the braking of a movement was indicated by the myoelectrical pattern of activity, particularly in slow large side bendings, where ipsilateral activity was present at the end of the movement. Sagittal movements starting at different initial trunk inclinations resulted in shifts in onset time and duration between antagonist muscles. The observed modifications are specific adaptations of the motor program to balance changes in mechanical conditions, such as angular acceleration, moment arm for the gravitational force, and intrinsic forces of active and passive structures surrounding the spine and pelvis. In conclusion, the present results demonstrate that trunk movements are generated and controlled by specific patterns of muscle coordination.

Arm movement performance during reversible basal ganglia lesions in the monkey.

Arm motor performance of eight Cebus monkeys was examined during reversible cooling in the ventral lateral region of the putamen and globus pallidus (primarily the external segment), where neurons discharging during arm movements have been found (DeLong 1972). When attempting to hold a handle stationary during basal ganglia cooling, all monkeys developed flexion at the wrist and some developed a slow flexion drift of the arm at the elbow. The prominence of wrist flexion emphasizes that the basal ganglia may normally influence distal musculature. During basal ganglia cooling an increase in segmental stretch reflexes (15-30 ms) was sometimes observed following arm perturbations, but no consistent increase occurred in the later EMG responses (30-95 ms) in contrast to results obtained in Parkinsonian patients (Tatton and Lee 1975). No major changes were observed in the time of onset of the earliest EMG activity in the agonist muscle in a simple reaction time elbow movement task during basal ganglia cooling. Basal ganglia lesions produced major disorders in both flexion and extension movements including slowing of movements and rebound of the arm towards its initial position after onset of movement. These disorders were accompanied by an increase in tonic activity of both flexors and extensors while holding and by increased levels of cocontraction of agonists and antagonists during attempted movements. It is suggested that this basal ganglia disorder is due to a failure to achieve the correct balance of activity between agonists and antagonists that is appropriate for a particular motor act.

Crayfish Escape Behaviour: Commands for Fast Movement Inhibit Postural Tone and Reflexes, and Prevent Habituation of Slow Reflexes

ABSTRACT Organized behaviour requires central neural mechanisms to prevent the simultaneous occurrence of incompatible movements. We investigated neural pathways in crayfish that suppress slow flexion of the abdomen during rapid flexions (‘tailflips’) produced by a separate set of muscles. The slow flexors are innervated in each half segment of the abdomen by five motor neurones and one peripheral inhibitor. In isolated preparations of the abdominal nervous system, stimulation of identified command neurones, which trigger tailflips in intact animals, inhibited spontaneous activity in the motor neurones to the slow flexors and excited the peripheral inhibitor. These effects are mediated by a population of interganglionic interneurones interposed between the command cells and the slow flexor efferents. Slow flexor reflexes also were inhibited by escape commands. This inhibition includes pathways that act upon early stages of sensory input. As a result, habituation of reflexes, which normally is produced by repeated stimulation, is abolished if each sensory stimulus is preceded by a burst of impulses in the command neurone.

Integrated Actions and Functions of the Chief Flexors of the Elbow

A detailed electromyographic investigation of the actions of the biceps brachii (both heads), the brachialis, and the brachioradialis was carried out in twenty normal young adults with a Stanley Cox multi-channel electromyograph equipped with audio and cathode-ray units and a thirty-five-millimeter linagraph camera. Records on film were made simultaneously from four bipolar concentric-needle electrodes in each subject during a large variety of movements and positions of the upper limb with and without a load of two pounds. For each muscle and for each Inovelnent or Posture a general trend could be determined. However, what proved most striking was the wide range in the degrees of activity in the series and in the sequence of appearance and disappearance of activity during various movements. An appreciable number of muscles differed from the average or general trend for any movement. The muscles were completely inactive when the forearm was in the relaxed or resting position. The conclusions presented indicate the general trend of the behavior of these muscles in the majority of the subjects. The short and long heads of the biceps have similar, although not identical, actions except that the long head of the biceps is generally more active in most of the movements. The biceps is a flexor, both isometric and isotonic, of the supine forearm under all conditions and is a flexor of the semiprone forearm when a load is lifted. However, it plays little or no part in the flexion of the prone forearm even when a load of two pounds is lifted. The biceps (both heads) is not a supinator of the extended forearm unless supination is firmly resisted ; ordinary supination is performed chiefly by the supinator. The biceps takes part in flexion of the shoulder joint, showing a slight activity in both heads, but it is not active in abduction unless the forearm is supinated. The brachialis is active during flexion of the forearm under all conditions and is generally active during most movements and postures. It is a flexor par excellence and is the workhorse of the elbow joint. The brachioradialis comes into action either during quick flexion of the forearm or when weight is lifted during slow flexion, especially of the semiprone and prone forearm. It is a reserve which is called upon when quick or powerful movements are required. The brachioradialis acts neither in supination of the extended prone forearm nor in pronation of the extended supine forearm unless these movements are strongly resisted. All three muscles act simultaneously, with the greatest activity when weight is lifted during flexion of the semiprone forearm. The antagonistic activity of the muscles during slow extension shows variable patterns, with the brachialis generally always active. During quick extension, the short, sharp burst of activity (found in all the muscles, but most pronounced in the biceps) probably is the result of a protective stretch reflex.

RESULTS OF STIMULATION OF THE TEGMENTUM WITH THE HORSLEY-CLARKE STEREOTAXIC APPARATUS

A number of investigators have stimulated electrically the cut surface of the mesencephalon in decerebrate animals and have described in detail the reactions elicited. The literature related to such experiments has been reviewed by Hinsey, Ranson and Dixon. 1 In general, stimulation of the pyramidal fibers in the basis pedunculi has been found to cause a rapid flexion of the fore and hind limbs of the side opposite to that stimulated, followed, on cessation of the stimulus, by prompt relaxation. However, when the stimulus is applied to the tegmentum there occurs a slow flexion of the ipsolateral fore limb and extension of the contralateral fore limb, these reactions persisting for some seconds after stimulation has ceased. Associated with these movements is a curvature of the spinal column which bends the trunk so that it offers a concavity toward the stimulated side. This curvature turns the head and tail toward the