Elbow Joint Position Research Articles

A model of open-loop control of equilibrium position and stiffness of the human elbow joint

According to the equilibrium point theory, the control of posture and movement involves the setting of equilibrium joint positions (EP) and the independent modulation of stiffness. One model of EP control, the alpha-model, posits that stable EPs and stiffness are set open-loop, i.e. without the aid of feedback. The purpose of the present study was to explore for the elbow joint the range over which stable EPs can be set open-loop and to investigate the effect of co-contraction on intrinsic low-frequency elbow joint stiffness (K (ilf)). For this purpose, a model of the upper and lower arm was constructed, equipped with Hill-type muscles. At a constant neural input, the isometric force of the contractile element of the muscles depended on both the myofilamentary overlap and the effect of sarcomere length on the sensitivity of myofilaments to [Ca2+] (LDCS). The musculoskeletal model, for which the parameters were chosen carefully on the basis of physiological literature, captured the salient isometric properties of the muscles spanning the elbow joint. It was found that stable open-loop EPs could be achieved over the whole range of motion of the elbow joint and that K (ilf), which ranged from 18 to 42 N m.rad(-1), could be independently controlled. In the model, LDCS contributed substantially to K (ilf) (up to 25 N m.rad(-1)) and caused K (ilf) to peak at a sub-maximal level of co-contraction.

Changes in Head and Neck Position Have a Greater Effect on Elbow Joint Position Sense in People With Whiplash-associated Disorders

It has been shown that perception of elbow joint position is affected by changes in head and neck position. Further, people with whiplash-associated disorders (WAD) present with deficits in upper limb coordination and movement. This study is aimed to determine whether the effect of changes in head position on elbow joint position error (JPE) is more pronounced in people with WAD, and to determine whether this is related to the participant's pain and anxiety levels. Nine people with chronic and disabling WAD and 11 healthy people participated in this experiment. The ability to reproduce a position at the elbow joint was assessed after changes in the position of the head and neck to 30 degrees , and with the head in the midline. Pain was monitored in WAD participants. Absolute elbow JPE with the head in neutral was not different between WAD and control participants (P=0.5). Changes in the head and neck position increased absolute elbow JPE in the WAD group (P<0.05), but did not affect elbow JPE in the control group (P=0.4). There was a connection between pain during testing and the effect of changes in head position on elbow JPE (P<0.05). Elbow JPE is affected by movement of the head and neck, with smaller angles of neck rotation in people with WAD than in healthy individuals. This observation may explain deficits in upper limb coordination in people with WAD, which may be due to the presence of pain or reduced range of motion in this population.

Do you know where your arm is if you think your head has moved?

Reproduction of a previously presented elbow position is affected by changes in head position. As movement of the head is associated with local biomechanical changes, the aim of the present study was to determine if illusory changes in head position could induce similar effects on the reproduction of elbow position. Galvanic vestibular stimulation (GVS) was applied to healthy subjects in supine lying. The stimulus was applied during the presentation of an elbow position, which the subject then reproduced without stimulation. In the first study, 13 subjects received 1.5 mA stimuli, which caused postural sway in standing, confirming that the firing of vestibular afferents was affected, but no illusory changes in head position were reported. In the second study, 13 subjects received 2.0-3.0 mA GVS. Six out of 13 subjects reported consistent illusory changes in head position, away from the side of the anode. In these subjects, anode right stimulation induced illusory left lateral flexion and elbow joint position error towards extension (p=0.03), while anode left tended to have the opposite effect (p=0.16). The GVS had no effect on error in subjects who did not experience illusory head movement with either 1.5 mA stimulus (p=0.8) or 2.0-3.0 mA stimulus (p=0.7). This study demonstrates that the accuracy of elbow repositioning is affected by illusory changes in head position. These results support the hypothesis that the perceived position of proximal body segments is used in the planning and performance of accurate upper limb movements.

Using the change of angular momentum and muscle electromyography data to qualify the muscle function in tennis forehand volley

Locomotion is key to survival, yet it can be disturbed by injuries, diseases, and aging. Therefore, it is important for researchers in biology, neuroscience, biomechanics, and further afield. Locomotion is frequently quantified using kinematic data, and quadrupeds including rodents are medical model animals used worldwide. Kinematics typically result from the tracking of some landmarks, often joint centers. Although commercially available systems and software exist for the analysis of these kinematic data, they are expensive, often restricted to use with a given apparatus, and may be inextensible. Therefore, there is a need for an open source tool to analyze kinematic data. We present a Python software to address this need. It uses 2D coordinates from four cameras and DLT coefficients from the calibrated volume to generates 3D coordinates [1]. A method is presented to modify the knee and elbow joint positions in 3D. Then, kinematic features are extracted, and they are sorted in a time series format to plot a summary of a study. In addition, we generate videos from the tracked points, 3D reconstruction of the points, showing joint angles for eight joints, the location of animal on the belt, and the animal's speed on the belt. The software has been evaluated by eight trials to show the importance of the work. The 3D reconstruction error, having an average of 7.36 pixels, was calculated for the markers. The presented program can be used in different fields. It will encourage the researchers to design the studies based on their needs because they can change the setup in any required conditions while they can extract the kinematic data.

Illusory changes in head position induced by neck muscle vibration can alter the perception of elbow position.

Acuity for elbow joint position sense (JPS) is reduced when head position is modified. Movement of the head is associated with biomechanical changes in the neck and shoulder musculoskeletal system, which may explain changes in elbow JPS. The present study aimed to determine whether elbow JPS is also influenced by illusory changes in head position. Simultaneous vibration of sternocleidomastoid (SCM) and the contralateral splenius was applied to 14 healthy adult human subjects. Muscle vibration or passive head rotation was introduced between presentation and reproduction of a target elbow position. Ten out of 14 subjects reported illusions consistent with lengthening of the vibrated muscles. In these 10 subjects, absolute error for elbow JPS increased with left SCM/right splenius vibration but not with right SCM/left splenius vibration. Absolute error also increased with right rotation, with a trend for increased error with left rotation. These results demonstrated that both actual and illusory changes in head position are associated with diminished acuity for elbow JPS, suggesting that the influence of head position on upper limb JPS depends, at least partially, on perceived head position.

EMG and MMG of agonist and antagonist muscles as a function of age and joint angle

The aim of this study was to determine the effect of elbow joint position on electromyographic (EMG) and mechanomyographic (MMG) activities of agonist and antagonist muscles in young and old women. Surface EMG and MMG were recorded from the triceps and biceps brachii, and brachioradialis muscles during isometric elbow extensions in young and old women. The measurements were carried out at an optimal joint angle ( A o), as well as at smaller ( A s = A o − 30°) and larger ( A l = A o + 30°) angles. The normalized to force EMG amplitude (RMS-EMG/ F) was smaller in old women compared to young in all muscles. The RMS-EMG/ F of the triceps brachii muscle was not affected by muscle length while that of the biceps brachii and brachioradialis muscles increased at shortest muscle length in both groups. The normalized to force MMG amplitude (RMS-MMG/ F) was smaller in old than in young in the triceps brachii muscle only. There was an increase in RMS-MMG/ F with triceps brachii and biceps brachii muscle shortening in both groups, and in the brachioradialis muscle – in young only. Compared to young, older women exhibited a bigger force fluctuation during maximum voluntary contraction, but these did not contribute significantly to the RMS-MMG. Skinfold thickness accounted for the RMS-EMG/ F and RMS-MMG/ F differences seen between old and young women in the biceps brachii muscle only. It is concluded that, the EMG and MMG response to muscles length change in agonist and antagonist muscles is generally similar in old and young women but the optimal angle shifts toward a bigger value in older women.

Changes in head and neck position affect elbow joint position sense

Changes in the position of the head and neck have been shown to introduce a systematic deviation in the end-point error of an upper limb pointing task. Although previous authors have attributed this to alteration of perceived target location, no studies have explored the effect of changes in head and neck position on the perception of limb position. This study investigated whether changes in head and neck position affect a specific component of movement performance, that is, the accuracy of joint position sense (JPS) at the elbow. Elbow JPS was tested with the neck in four positions: neutral, flexion, rotation and combined flexion/rotation. A target angle was presented passively with the neck in neutral, after a rest period; this angle was reproduced actively with the head and neck in one of the test positions. The potential effects of distraction from head movement were controlled for by performing a movement control in which the head and neck were in neutral for the presentation and reproduction of the target angle, but moved into flexion during the rest period. The absolute and variable joint position errors (JPE) were greater when the target angle was reproduced with the neck in the flexion, rotation, and combined flexion/rotation than when the head and neck were in neutral. This study suggests that the reduced accuracy previously seen in pointing tasks with changes in head position may be partly because of errors in the interpretation of arm position.

The Effects Of Exercise Induced Muscle Injury On Knee Joint Position Sense

The effect of fatigue and injury on joint position sense is reported throughout the literature. However, there are few studies that have looked at the effects of exercise induced muscle injury on joint position sense. PURPOSE To evaluate the effects of exercise induced muscle injury in the quadriceps on weight bearing knee joint position sense. METHODS Twenty healthy college age students (21.7 ± 2.0 yrs, 169.85 ± 11.49 cm, 68.89 ± 15.82 kg) volunteered to participate in the study. Measurement of knee position sense was done with the subject in a standing weight-bearing position with both knees fully extended, and feet approximately shoulder width apart and in a position of slight external rotation. The subjects were instructed to perform a twolegged squat to specific knee flexion angles (20, 30, 40, 50, and 60°) in a randomized order. The test angle was held for 5 seconds, after which the subjects actively returned to the starting position. After a 7 second interval, they returned to what was perceived as the test angle. Each angle represented one trial for a total of five trials. The absolute angle error (AAE) was measured for each test angle using an electrogoniometer attached to the lateral aspect of the dominant leg. The output was recorded on a differential amplifier and displayed on the Biopac Electromyography system. AAE was the absolute difference between the test angle and the perceived angle. The average absolute angle error was calculated for each test angle and then averaged for each baseline and test session. Following baseline testing, eccentric knee flexion exercises on a Hammer Strength Leg Extension machine was performed. The protocol involved continuous eccentric knee flexion repetitions on a four second count. Once the participants could no longer lower the weight on a four second count, the weight was decreased and the exercise was continued. The exercise was terminated when the subjects could no longer support a 7 kg weight. Following the exercise-induced muscle injury subjects returned 24, 48, and 72 hours for retesting on knee joint position sense. A one-way repeated measures ANOVA was used. RESULTS The average AAE means for each condition were: baseline (3.43±1.30), 24 h (3.44±1.43), 48 h (4.03±1.89) and 72 h (3.74±1.39). There was no significant effect of time on average absolute angle error (F1,3= .917, P= .439). CONCLUSIONS In this study there were no significant differences between baseline 24, 48, and 72 hour average absolute angle error. This is opposite of what was observed in previous studies that evaluated the effects of exercise induced muscle injury on elbow joint position sense. Therefore, further research should be conducted on this topic.

The Effects Of Exercise Induced Muscle Injury On Knee Joint Position Sense

The effect of fatigue and injury on joint position sense is reported throughout the literature. However, there are few studies that have looked at the effects of exercise induced muscle injury on joint position sense. PURPOSE To evaluate the effects of exercise induced muscle injury in the quadriceps on weight bearing knee joint position sense. METHODS Twenty healthy college age students (21.7 ± 2.0 yrs, 169.85 ± 11.49 cm, 68.89 ± 15.82 kg) volunteered to participate in the study. Measurement of knee position sense was done with the subject in a standing weight-bearing position with both knees fully extended, and feet approximately shoulder width apart and in a position of slight external rotation. The subjects were instructed to perform a twolegged squat to specific knee flexion angles (20, 30, 40, 50, and 60°) in a randomized order. The test angle was held for 5 seconds, after which the subjects actively returned to the starting position. After a 7 second interval, they returned to what was perceived as the test angle. Each angle represented one trial for a total of five trials. The absolute angle error (AAE) was measured for each test angle using an electrogoniometer attached to the lateral aspect of the dominant leg. The output was recorded on a differential amplifier and displayed on the Biopac Electromyography system. AAE was the absolute difference between the test angle and the perceived angle. The average absolute angle error was calculated for each test angle and then averaged for each baseline and test session. Following baseline testing, eccentric knee flexion exercises on a Hammer Strength Leg Extension machine was performed. The protocol involved continuous eccentric knee flexion repetitions on a four second count. Once the participants could no longer lower the weight on a four second count, the weight was decreased and the exercise was continued. The exercise was terminated when the subjects could no longer support a 7 kg weight. Following the exercise-induced muscle injury subjects returned 24, 48, and 72 hours for retesting on knee joint position sense. A one-way repeated measures ANOVA was used. RESULTS The average AAE means for each condition were: baseline (3.43±1.30), 24 h (3.44±1.43), 48 h (4.03±1.89) and 72 h (3.74±1.39). There was no significant effect of time on average absolute angle error (F1,3= .917, P= .439). CONCLUSIONS In this study there were no significant differences between baseline 24, 48, and 72 hour average absolute angle error. This is opposite of what was observed in previous studies that evaluated the effects of exercise induced muscle injury on elbow joint position sense. Therefore, further research should be conducted on this topic.

Effect of load level and muscle pain intensity on the motor control of elbow-flexion movements

This study assessed interactions between mild/moderate muscle pain and inertial load on the control of human elbow-flexion movements. It is hypothesized that high inertial load combined with moderate muscle pain intensity affect the motor control more than for low inertial-load combined with low-intensity pain. Fifteen subjects performed horizontal pointing movements (70 degree range) under three load conditions: 0, 4, and 10 kg. Pain was induced by injection of 0.5 ml and 1.5 ml hypertonic saline into the biceps muscle. Subjects scored the muscle pain intensity on a visual analogue scale (VAS). Elbow joint position, VAS, and the electromyograms (EMG, m. biceps brachii, m. triceps brachii, m. brachioradialis, and m. trapezius) were recorded. Mild and moderate muscle pain attenuated acceleration profiles [6.1(0.9)%], effective movement amplitude [3.2 (0.7)%], peak velocity [5.8 (0.9)%] and prolonged the reaction time [21 (5)%]. No interaction between muscle pain intensity and inertial load was found for the kinematic parameters. EMG profiles from m. biceps brachii, m. triceps brachii, and m. brachioradialis were similarly attenuated [10.2 (0.80)%] by mild and moderate muscle pain in all inertial load conditions. For high inertial load, the initial agonist EMG burst activity was more attenuated [50 (5.3)%] by moderate muscle pain compared with mild muscle pain [34 (4.2)%]. These data suggest that for high effort-demanding tasks muscle pain differently affects the motor planning according to the pain-intensity level. Perturbations of motor planning lead to changes on movement strategies, which might be a potential cause of musculoskeletal problems.

The neural control of single degree-of-freedom elbow movements. Effect of starting joint position.

It is known that muscle activation patterns are changed when the force requirements of a task are increased (e.g., moving a heavier inertial load) or when the available muscle force is reduced (e.g., by inducing muscle fatigue). It is not known whether this is true when the torque-producing capability of a muscle is altered. Eight neurologically healthy subjects performed flexion and extension maximum voluntary isometric contractions (MVC) at five different joint positions (10 degrees, 40 degrees, 70 degrees, 100 degrees, and 130 degrees, where 0 degrees is full elbow extension). Flexion MVC increased by 138% and extension MVC increased by 74% as the elbow joint position changed from the most extended to the most flexed position tested. The same subjects then made rapid, 30 degrees elbow flexion movements from each of four starting elbow positions (10 degrees, 40 degrees, 70 degrees, and 100 degrees). Muscle activation patterns for movements made from the more extended positions showed an increased first agonist burst duration and increased latency of the antagonist burst. There was no change in the initial rate of rise of the agonist burst across starting joint positions. Movements made from the most extended starting position were significantly slower and had longer acceleration and deceleration times than did movements made from the more flexed starting positions. The changes in muscle activation patterns were consistent with those seen when the force requirements of a task are increased or the available muscle force is reduced. We hypothesize that a fall in the ratio of available to required muscle forces causes the nervous system to change muscle activation patterns, to increase the ratio. Our results are consistent with this hypothesis.

Identification of unilateral elbow-joint position is impaired by Parkinson's disease.

We have compared the ability of patients with idiopathic Parkinson's disease (PD) with that of control subjects to identify unilateral elbow-joint position, in the absence of direct vision of the arm, by visual reference to a graduated angular scale, placed beside the elbow, across a range of test angles of 90-108 degrees. The positioning of the subject's elbow was achieved under either passive (subject relaxed, Experiment 1) or active (subject contracting, Experiment 2) conditions. PD patients' performance (while on L-dopa medication) with the elbows on the sides of "worse" and "better" motor signs was compared with that of controls with, respectively, the left and right elbows. In both experiments, (a) both the individual, overall mean unsigned (with respect to direction) error averaged across all test angles (accuracy), and the SD about this mean (precision), were significantly larger on each side among PD patients than among controls, and (b) the subjective ranges of values employed by PD patients were substantially compressed, on average, by comparison with those of controls. Within-group analyses revealed that (a) among control subjects, but not among PD subjects, individual, overall mean unsigned errors, on each side, averaged across test angles, were significantly smaller under active than under passive conditions, and (b) the subjective ranges employed by PD patients, but not by controls, under active conditions significantly exceeded those under passive conditions. We conclude that these results are generally consistent with the notion that PD impairs unilateral elbow-joint position sense.

Apparatus for measuring and perturbing shoulder and elbow joint positions and torques during reaching

Visually guided reaching movements by monkeys has become an important paradigm for examining the function of various sensory and motor areas of the brain. However, a major problem with interpreting neural discharge during this motor task has been the difficulty to quantify and manipulate the mechanics of movement. To address this problem, a new experimental facility has been developed to allow neural recordings in a monkey while it makes movements with a mechanical linkage attached to its arm. The device (KINARM) has hinge joints aligned with the monkey’s shoulder and elbow and allows the monkey to make arm movements in the horizontal plane. Custom-made fibreglass braces attach the linkage to the monkey’s forearm and arm. Motors attached to the mechanical linkage provide angular position of the joints and apply torques either to the shoulder or elbow, or both. The KINARM is used in concert with a computer projection system that provides virtual targets in the plane of the arm. Preliminary results illustrate the ability of a monkey to perform a variety of multi-joint motor tasks under various static and dynamic loads.

ESTIMATION OF ELBOW JOINT POSITION BEFORE, DURING, AND FOLLOWING A 17-DAY SPACEFLIGHT.

1920 The ability to estimate elbow joint position was tested in four male astronauts before (-30 and -12 days), during (1, 4, 9, and 15 days), and after(+1, +5, +9, and +16 days) a 17-day spaceflight (STS-78). Subjects were asked to estimate 90 ° or 135 ° joint angles during passive (relaxed) and active (10% maximal agonist effort) isokinetic extension (EXT) and flexion(FLX). Subjects also estimated these joint positions during low resistance isotonic EXT. For each angle, 6 (isokinetic) and 3 (isotonic) trials were requested in random order. Across all test conditions, the mean angle estimate ranges were 93 °-118 ° and 119 °-152 ° for requested angles of 90 ° and 135 °, respectively. Subjects overestimated the 90 ° position across all conditions, whereas the accuracy of the 135 ° estimate varied. Angle estimates were most accurate during isokinetic FLX for 90 °(mean error +9.8 °) and isokinetic EXT for 135 ° (mean error +0.7°). No differences occurred between passive vs. active isokinetic EXT or FLX. Estimates of each joint angle during isokinetic EXT were less than isotonic EXT, but greater than isokinetic FLX (P<0.05). During spaceflight, joint angle estimates were lower during isokinetic FLX and EXT for 90 °(P<0.05) and 135 ° (P≤0.10) compared to preflight. Spaceflight also decreased angle estimates during isotonic FLX and EXT (P<0.05). Elbow angle estimates had returned to preflight values one day after return to 1G. These data demonstrate that elbow joint angle estimation was: 1) decreased during spaceflight, particularly for isotonic conditions 2) rapidly restored to preflight values upon return to 1G; and 3) not changed by low level agonist muscle exertion during isokinetic movements. These data indicate that the proprioception of elbow joint position is altered by microgravity, but rapidly readapts to preflight control values after return to 1G.

Discharge characteristics of the elbow joint nerve of the cat

Direct recordings were made from intact elbow joint nerves (EJN) in decerebrate cats. These multiunit recordings indicate that the EJN is a relatively pure articular nerve and does not contain significant numbers of muscle afferent fibres. In every cat the EJN exhibited a tonic discharge throughout a full range of elbow joint positions. The discharge was most intense when the elbow was extended to 165° and least intense when the joint was held in midrange positions between 90° and 120°. There was a modest increase in discharge as the elbow was held in more flexed positions and activity at 30° was about half of that at 165°. Alterations in the tone of muscles around the joint did not affect the adapted EJN discharge at anyangle.

The effect of elbow joint afferent discharge on transmission in forelimb flexion reflex pathways to biceps and triceps brachii in decerebrate cats

The present experiments were performed to investigate the influence of elbow joint afferent discharge on the excitability of reflex arcs mediating flexion withdrawal and crossed extensor reflexes in the forelimb muscles of decerebrate cats. The excitability of flexion withdrawal and crossed extensor reflexes in forelimb muscles was shown to be modulated by elbow joint position. Flexion withdrawal reflexes were most easily elicited when the elbow was extended and crossed extensor reflexes were most easily elicited when the elbow was flexed. This modulation of transmission was not confined to reflex pathways projecting to muscles acting at the elbow but also included pathways to muscles acting at the wrist and shoulder in addition to muscles in the contralateral forelimb. The changing excitability of reflex pathways caused by elbow movement was unaltered by degloving the skin covering the join and tenotomy of the medial head of triceps and the long head biceps. However, modulation of reflex excitability by joint movement was totally abolished by local anaesthesia of the joint in an otherwise intact limb. Thus, the present experiments indicate that transmission in forelimb flexion reflex pathways can be powerfully influenced by elbow joint afferent discharge.

絶対筋力におよぼす静的および動的筋力トレーニングの影響

The purpose of this study was to observe the difference of training effect on the absolute muscle strength between static and dynamic strength training. The subjects were 14 adult males of whom 7 were exposed to static training and others to dynamic training. All subjects were trained every day for 12 weeks except Sundays. Training intensity was two-thirds of maximum isometric strength in static training group (S-group) and two-thirds of one repetition maximum (1RM) in dynamic training group (D-group). In S-group muscle strength was exerted statically for 1O seconds on the right angle of the elbow joint. In D-group the elbow joint was flexed between 75 and 105 degrees of the angle of elbow joint with the rhythm of one repetition in two seconds using audiovisual metronome, and it was repeated five times in a set. All training exercises for both groups were given three sets in a day. The cross-sectional area of elbow flexor muscle was measured at the extended position of the elbow joint before and after training by means of ultrasonic method, and the absolute muscle strength was calculated. The results were as follows: 1)Maximum isometric strength significantly increased (p < 0.001) by 25.9±4.2% (mean ± standard error) in S-group and 30.7±3.8% in D-group. No significant difference of strength increase was observed between dynamic and static training group. 2)The dynamic strength, measured as 1RM significantly increased (p < 0.001) by 22.7±1.1% in S-group and by 33.1±4.0% in D-group. The increase of 1RM in D-group was significantly higher than that in S-group. 3)1RM was about 70% of isometric maximum strength, which value was not affected by both training programs. 4)Cross-sectional area of muscle increased significantly by 5.4±1.4% (p < 0.01) in S-group and 3.2±1.3% (p < 0.05) in D-group. No significant difference in increase of muscle area was observed between S- and D-group. 5)Absolute muscle strength increased by training up to about 9.7kg/cm^2 (muscle area measured at extended position of elbow joint) in both training groups.