Elbow Extensors Research Articles

Whey protein and high-volume resistance training in postmenopausal women.

To examine the combined effects of whey protein supplementation and low intensity, high-volume resistance training in healthy postmenopausal women. Postmenopausal women (n=12; age: 57 ± 4.7 years, weight: 75 ± 17.4 kg, height: 163 ± 5.5 cm, body mass index: 28.3 ± 7.0) consumed whey protein (4 x 10 gram aliquots) or placebo (maltodextrin) during unilateral resistance training sessions 2 days per week (Monday, Thursday) and consumed the opposite beverage during training the other side of the body on alternating days (Tuesday, Friday) for 10 weeks. Participants performed 3 sets at 30% baseline 1-repetition maximum (1RM) to volitional muscle fatigue for 4 exercises (leg curl, biceps curl, leg extension, triceps extension). Prior to and following training, assessments were made for upper and lower limb lean tissue mass (dual energy x-ray absorptiometry), muscle thickness of the elbow and knee flexors and extensors (ultrasound) and muscle strength (1RM leg curl, biceps curl, leg extension, triceps extension). There was a significant increase over time for muscle strength (biceps curl, leg extension, triceps extension; P = 0.006) and muscle thickness (elbow flexors and extensors; P = 0.022) with no differences between whey protein and placebo. High volume resistance training is effective for improving some indices of muscle mass and strength in postmenopausal women, but the strategic ingestion of whey protein during training sessions does not augment this response.

Acute Testosterone Deficiency Affects Electrical Properties Of Elbow Flexors And Extensors During Voluntary Contractions

Testosterone (T) is a powerful androgenic anabolic steroid (AAS) capable to induce diverse biological modifications both in the nervous system and in the skeletal muscle. Nevertheless, no previous study investigated the effect of T on the neuromuscular control in intact human muscles. PURPOSE: This study aims at assessing the acute effects of reduced T serum concentration on the neuromuscular control in intact human muscle. METHODS: Off-therapy hypogonadal (HY= 9) and eugonadal (EU = 15) volunteers were asked to perform isokinetic elbow flexion-extension at different angular velocities (AV: 0-30-60-120-180- 240°/s). For any considered AV, three cycles were performed. Between each attempt (AV), 5-minute rest were granted. Surface electromyograms (sEMG) of Biceps Brachii (BB) and Triceps Brachii (TB) were recorded in differential mode with two four linear array electrodes. sEMG and torque data were recorded synchronously at a sampling frequency of 2048 Hz. For any AV, during flexion and extension, the maximal torque among the three cycles was detected and used to compare group means. For both BB and TB and for all the considered AV, agonist (AGBB; AGTB) and antagonist (ANBB; ANTB) activation was expressed as a ratio of the agonist activation observed at 0°/s. Furthermore, the median frequency (MDF) of the sEMG power spectrum was computed for both the BB and the TB (MDFBB; MDFTB) at any AV considered. Muscle fiber conduction velocity of the BB (CVBB) was estimated as well. RM-ANOVA was performed to compare group means in mechanical and electromyographic parameters. RESULTS: No main effect of group was observed for peak torque, during flexion (p = .38) and extension (p = .74) and for AGBB (p = .44), AGTB (p = .93), ANBB (p = .99) and ANTB (p = .96). A significant effect of group was observed for MDFTB (p = .02; group mean ± SD. EU: 97.1 ± 14.0; HY: 83.5 ± 9.4) and a trend (p = .05) towards lower MDFBB in the HY group (group mean ± SD. EU: 88.1±15.0; HY: 77.1±13.9). The HY group showed a trend towards lower CVBB (p = .06; EU: 4.5 ± 0.6; HY: 4.1 ± 0.2) CONCLUSION: Since MDF and CV have been associated with motor unit recruitment strategies, the lower MDF and CVBB observed in the HY group seem to reflect a decreased ability to recruit motoneuron pools, which might lead to the well documented force loss following chronic exposure to a reduced T concentrations.

Dose-response of 1, 3, and 5 sets of resistance exercise on strength, local muscular endurance, and hypertrophy.

The study's purpose was to compare the response of performing 1, 3, and 5 sets on measures of performance and muscle hypertrophy. Forty-eight men, with no weight training experience, were randomly assigned to one of the 3 training groups, 1 SET, 3 SETS, 5 SETS, or control group. All training groups performed 3 resistance training sessions per week for 6 months. The 5 repetition maximum (RM) for all training groups increased in the bench press (BP), front lat pull down (LPD), shoulder press (SP), and leg press (LP) (p ≤ 0.05), with the 5 RM increases in the BP and LPD being significantly greater for 5 SETS compared with the other training groups (p ≤ 0.05). Bench press 20 RM in the 3-SET and 5-SET groups significantly increased with the increase being significantly greater than the 1-SET group and the 5-SET group increase being significantly greater than the 3-SET group (p ≤ 0.05). LP 20 RM increased in all training groups (p ≤ 0.05), with the 5-SETS group showing a significantly greater increase than the 1-SET group (p ≤ 0.05). The 3-SET and 5-SET groups significantly increased elbow flexor muscle thickness (MT) with the 5-SET increase being significantly greater than the other 2 training groups (p ≤ 0.05). The 5-SET group significantly increased elbow extensor MT with the increase being significantly greater than the other training groups (p ≤ 0.05). All training groups decreased percent body fat, increased fat-free mass, and vertical jump ability (p ≤ 0.05), with no differences between groups. The results demonstrate a dose-response for the number of sets per exercise and a superiority of multiple sets compared with a single set per exercise for strength gains, muscle endurance, and upper arm muscle hypertrophy.

Changes in Anconeus Motor Unit Firing Rates During High-Intensity Dynamic Elbow Extensor Fatiguing Contractions

Changes in Anconeus Motor Unit Firing Rates During High-Intensity Dynamic Elbow Extensor Fatiguing Contractions

Electromyographic Cross-Spectral Analysis of Antagonist Muscle Coactivation

The purpose of this study was two-fold: (1) to compare the responses for traditional EMG amplitude measures with those from the crossspectrum approach for assessing agonist-antagonist interaction, and (2) to examine changes in the agonist-antagonist interaction for the elbow flexors and extensors with increases in movement velocity. Eighteen healthy, college-aged subjects (mean ± SD age = 21.8 ± 2.7 yrs) volunteered to perform maximal, concentric isokinetic contractions of the dominant elbow flexors and extensors at randomly ordered velocities of 60, 180, and 300 degrees/second. The subjects also performed maximal, 6-sec isometric contractions of the dominant elbow flexors and extensors at an elbow joint angle of 120 degrees between the arm and forearm. During all contractions, bipolar surface EMG signals were detected from the biceps brachii and triceps brachii. Traditional EMG amplitude (root-mean-square, RMS) measurements were made for both the agonist and antagonist muscles during each contraction. In addition, total power and mean frequency (MNF) were calculated from the agonist-antagonist muscle cross-spectrum. The results indicated that there were no velocity-related changes in traditional EMG amplitude for either the agonist or antagonist muscles. There were also velocity related changes in cross-spectral power, but not MNF, for both elbow flexion and elbow extension. Mean crossspectral power values were similar when comparing elbow flexion versus elbow extension during isometric contractions. During the dynamic contractions, however, mean cross-spectral power values were lower (relative to the isometric values) at all velocities for elbow extension, but higher at all velocities for elbow flexion. These findings suggested that the agonist-antagonist cross-spectrum approach may provide information regarding agonist-antagonist interaction that cannot be obtained from traditional EMG amplitude measurements. In addition, the agonist-antagonist interaction may be different for elbow flexion versus elbow extension.

Increased antagonist muscle activity in cervical SCI patients suggests altered reciprocal inhibition during elbow contractions

ObjectiveAfter spinal cord injury (SCI), the antagonist muscles activation is increased during voluntary contractions and reflex conditioning protocols. This increase can be the result of both muscle atrophy and reciprocal facilitation mechanism. It remains however unclear to what extent increased antagonist muscles activation could be rather attributable to central vs. peripheral changes during voluntary contractions achieved by SCI participants. MethodsWe investigated the activations of elbow extensors and flexors during isometric elbow flexion and extension contractions performed at 3 force levels by 10 healthy participants and 8 participants with cervical SCI (cSCI). ResultsAt similar force level and absolute net torque in flexion, the antagonist muscles activation was increased for the participants with cSCI. At similar absolute net torque in extension, the activations of agonist and antagonist muscles were increased for the participants with cSCI. ConclusionDuring flexion contractions, increased antagonist muscles activation may be explained by extensors atrophy or reciprocal facilitation. During extension contractions, increased antagonist muscles activation may reflect the importance of reciprocal facilitation as antagonist muscles were evaluated as intact by clinical testing and maximal net joint torque recording. SignificanceThese results in cSCI participants revealed an increased activation of antagonist muscles, which may reflect a reorganization of the spinal reflexes and their supraspinal control involved during isometric elbow contractions.

Relationship Between Fatigue and Changes in Swim Technique During an Exhaustive Swim Exercise.

To analyze the relationship between the responses of isometric peak torque (IPT) and maximal rate of force development (RFDmax) with the changes in stroking parameters in an exhaustive exercise performed in front crawl. Fifteen male swimmers performed, on different days, the following protocols: maximal 400-m trial, strength tests before and after an exhaustive test at 100% of the mean speed obtained during the 400-m test, and the same procedures on day 2. The IPT of elbow flexors (79.9 ± 19.4 and 66.7 ± 20.0 N·m) and elbow extensors (95.1 ± 28.0 N·m and 85.8 ± 30.5 N·m) was decreased after the swim test, as was RFDmax (521.8 ± 198.6 and 426.0 ± 229.9 N·m/s; 420.6 ± 168.2 and 384.0 ± 143.5 N·m/s, respectively). Stroke length decreased during the swim test (1.96 ± 0.22 and 1.68 ± 0.29 m/stroke), while stroke rate increased (37.2 ± 3.14 and 41.3 ± 4.32 strokes/min). The propulsive phases increased while the nonpropulsive phases decreased during the test. Significant correlation was found between the changes in IPT and stroke length, stroke rate and recovery (elbow flexors), and entry and catch phase (elbow extensors). In addition, significant correlation was found between the changes in RFDmax of elbow flexors with the changes in pull and recovery phases. Changes in swim technique during an exhaustive test can be, at least in part, associated with fatigue of the arm muscles.

Effects of Reinnervation of the Triceps Brachii on Joint Kinematics and Electromyographic Patterns of the Feline Forelimb during Level and Upslope Walking

Nerve injury in the hindlimb of the cat results in locomotor changes, yet these findings have not been explored in a more multifunctional forelimb. Kinematics and muscle activity of the shoulder and elbow during level and upslope locomotion following reinnervation of the feline long head of the triceps brachii (TLo) were evaluated (1) during paralysis [none to minimum motor activity (short-term effects)] and (2) after the motor function was recovered but the proprioceptive feedback was permanently disrupted (long-term effects). The step cycle was examined in three walking conditions: level (0%), 25% grade (14° upslope) and 50% grade (26.6° upslope). Measurements were taken prior to and at three time points (2 weeks, 1 month and 12+ months) after transecting and suturing the radial nerve of TLo. There was less of a yield (increased flexion) at the elbow joint and more extensor activity during elbow flexion during stance (E2) as the grade of walking increased. Substantial short-term effects were observed at the elbow joint (increased flexion during E2) as well as increased motor activity by the synergistic elbow extensors, and greater shoulder extension at paw contact, leading to altered interjoint coordination during stance. Forelimb shoulder and elbow kinematics during level and upslope locomotion progressed back to baseline at 12 months. The short-term effects can be explained by both mechanical and neural factors that are altered by the functional elimination of the TLo. Full recovery of the forelimb kinematics during level and upslope walking suggests that the proprioceptive length feedback loss is compensated by other sensory sources or altered central drive.

Intrinsic excitability of human motoneurons in biceps brachii versus triceps brachii.

The intrinsic excitability of spinal motoneurons is mediated in part by the presence of persistent inward currents (PICs), which amplify synaptic input and promote self-sustained firing. Studies using animal models have shown that PICs are greater in extensor motoneurons over flexor motoneurons, but this difference has not yet been demonstrated in humans. The primary objective of this study was to determine whether a similar difference exists in humans by recording from motor units in biceps and triceps brachii during isometric contractions. We compared firing rate profiles of pairs of motor units, in which the firing rate of the lower-threshold "control" unit was used as an indicator of common drive to the higher-threshold "test" unit. The estimated contribution of the PIC was calculated as the difference in firing rate of the control unit at recruitment versus derecruitment of the test unit, a value known as the delta-F (ΔF). We found that ΔF values were significantly higher in triceps brachii (5.4 ± 0.9 imp/s) compared with biceps brachii (3.0 ± 1.4 imp/s; P < 0.001). This difference was still present even after controlling for saturation in firing rate of the control unit, rate modulation of the control unit, and differences in recruitment time between test and control units, which are known to contribute to ΔF variability. We conclude that human elbow flexor and extensor motor units exhibit differences in intrinsic excitability, contributing to different neural motor control strategies between muscle groups.

Muscle torque and its relation to technique, tactics, sports level and age group in judo contestants.

The aim of this study was to perform a comparative analysis of maximal muscle torques at individual stages of development of athletes and to determine the relationship between muscle torques, fighting methods and the level of sports performance.The activity of 25 judo contestants during judo combats and the effectiveness of actions were evaluated. Maximum muscle torques in flexors/extensors of the body trunk, shoulder, elbow, hip and knee joints were measured. The level of significance was set at p≤0.05; for multiple comparisons the Mann-Whitney U test, p≤0.016, was used. Intergroup differences in relative torques in five muscle groups studied (elbow extensors, shoulder flexors, knee flexors, knee extensors, hip flexors) were not significant. In cadets, relative maximum muscle torques in hip extensors correlated with the activity index (Spearman’s r=0.756). In juniors, maximum relative torques in elbow flexors and knee flexors correlated with the activity index (r=0.73 and r=0.76, respectively). The effectiveness of actions correlated with relative maximum torque in elbow extensors (r=0.67). In seniors, the relative maximum muscle torque in shoulder flexors correlated with the activity index during the second part of the combat (r=0.821).

A DESCRIPTIVE PROFILE OF ISOMETRIC MUSCLE STRENGTH AND MUSCLE STRENGTH IMBALANCE IN YOUNG TENNIS PLAYERS

Background. Tennis is assumed as asymmetric sport, prolonged training practice could affect muscle strength imbalance. Muscle strength functional ratio imbalance could be a reason for poor posture, physical weakness and increased risk of injury. The purpose of the research was to evaluate young tennis players’ main muscle group strength topography and to investigate the level of different muscles groups’ bi-lateral and contra-lateral imbalance. Methods. The participants of the study were six young right handed competitive tennis players (girls, age 11.4 ± 0.5 years, tennis experience 4.7 ± 0.6 years). Examination of main muscles groups was performed with an isokinetic dynamometer. Results. Young tennis players have pronounced bi-lateral imbalance between shoulder joint extensors and flexors (25%), internal and external rotators (36%), left elbow flexors and extensors (58%), wrist pronator and supinator (the right hand 17%, left 48%), hip flexors and extensors (35%); knee joint flexors and extensors (60%); ankle dorsal flexors and plantar flexors (59%); spine and abdominal muscles (48%). It was detected that young tennis players have pronounced contra-lateral imbalance between right and left internal rotators of the shoulder joint (27%) and external rotators (26%), wrist joint supinators (41%). Conclusions. To avoid the increase in muscle bi-lateral imbalance it is highly recommended to pay more attention to shoulder adductors and shoulder external rotators, elbow flexors and extensors, wrist supinators and extensors, knee extensors, ankle plantar flexors and spine flexors. For contra-lateral imbalance prevention in addition to train non-dominant upper extremity muscles: shoulder internal and external rotators, wrist supinators.

Taping of the elbow extensor muscle in chronic stroke patients: comparison between before and after three-dimensional motion analysis.

[Purpose] This study aimed to observe the effect of kinesio taping on the quality of movement of each arm during a reaching task in patients with right-sided hemiparetic stroke. [Subjects and Methods] Sixteen right-handed participants who had had a right-sided hemiparetic stroke were requested to perform a reaching task with each arm, with and without kinesio taping. A three-dimensional motion analysis system was used to measure peak angular velocity, time to reach peak angular velocity, and movement units during elbow motion. [Results] In the right arm, movements during the reaching task with kinesio taping were faster, smoother, and more efficient than those without kinesio taping. The peak angular velocity increased, and the time to reach peak angular velocity decreased. Movement units decreased significantly. However, in the untaped arm, the movement was slower, rougher, and less efficient. [Conclusion] Kinesio taping provided a positive effect on the reaching movement of the taped arm of right-handed persons who had had a right-sided hemiparetic stroke.

Muscle hardness of the triceps brachii before and after a resistance exercise session: a shear wave ultrasound elastography study.

Muscle hardness indicates muscle condition, and its measurement before and after resistance exercise is essential for preventing resistance training-induced muscle injury. To investigate muscle hardness of the triceps brachii (TB) before and immediately after a resistance exercise session involving the elbow extensors. In 18 young men, muscle hardness of the long head of TB was measured at 50%, 60%, and 70% point along the length of the upper arm from the acromial process of the scapula to the lateral epicondyle of the humerus by using shear wave ultrasound elastography. At the same sites, muscle thickness of the long head of TB was also measured by ultrasonography. Resistance exercise was performed using a dumbbell with a mass adjusted to 80% of the one-repetition maximum. Although the exercise-induced increase in muscle hardness was significant at all the regions, muscle hardness was significantly higher at 70% of the upper arm length than at the other regions before and after resistance exercise. The exercise-induced increase in muscle thickness was also significant, but the relative changes in muscle hardness before and after resistance exercise were not correlated with the corresponding relative changes in muscle thickness at each region. These results indicate the small effect of exercise-induced muscle swelling on exercise-induced changes in muscle hardness. We suggest that muscle damage and/or injury, particularly at the distal region of TB, should be carefully considered to safely perform resistance exercise.

Usefulness of intermuscular coherence and cumulant analysis in the diagnosis of postural tremor

ObjectiveTo investigate the potential value of two advanced EMG measures as additional diagnostic measures in the polymyographic assessment of postural upper-limb tremor. MethodsWe investigated coherence as a measure of dependency between two EMG signals, and cumulant analysis to reveal patterns of synchronicity in EMG activity in muscle pairs. Eighty datasets were analyzed retrospectively, obtained from four groups: essential tremor (ET), Parkinson’s disease (PD), enhanced physiological tremor (EPT), and functional tremor (FT). ResultsIntermuscular coherence was highest in the PD group (0.58), intermediate in FT (0.43) and ET (0.40), and weakest in EPT (0.16) (p=0.002). EPT patients could be distinguished by low coherence: coherence <0.18 in the wrist+elbow extensors differentiates EPT in this sample with a sensitivity of 86% and specificity of 84%.Cumulant analysis showed predominantly alternating activity between wrist and elbow extensor in ET patients, while a more synchronous pattern was predominant in PD, EPT and FT (p=0.008). EMG activity in wrist and elbow flexors tended to be more synchronous in PD (p=0.059). ConclusionOur results suggest that coherence and cumulant analysis may be of additional value in the diagnostic work-up of postural tremor. SignificanceThese additional measures may be helpful in diagnosing difficult tremor cases.

Natural history of skeletal muscle involvement in myotonic dystrophy type 1: a retrospective study in 204 cases.

Myotonic dystrophy type 1 (DM1) is the most frequent muscular dystrophy in adult. The aim of this study was to investigate the natural history of skeletal muscle weakness in adults, in a cross-sectional, retrospective study. In a cohort of 204 adult DM1 patients, we quantified muscle impairment, handgrip force and physical disability. Muscle strength was similarly affected in the legs and in the arms, the right and left side, and distally more than proximally in patients. The earliest and the most affected skeletal muscles were the digit flexors, foot dorsiflexors and neck flexors; whereas the elbow and knee extensors and flexors were the least affected muscle groups. The rate of decline of the muscle strength was -0.111 units/year. The handgrip values were lower in DM1 patients than the normative values and the rate of decline in handgrip force per year was -0.24 kg. Limitation in mobility or walking is observed in 84 % of DM1 patients but requirement of wheelchair is infrequent (3 %). The decrease in muscle strength, handgrip force and the increase in physical disability were highly correlated with duration of the disease and the number of CTG repeats in the blood. Significant association was found between decline in muscle strength and the age at onset, physical disability and the age of patients at evaluation, handgrip force and gender. Decline in muscle weakness is very slow and although limitation when walking is a common manifestation of DM1 in patients, the requirement of wheelchair is infrequent.

Short-Term Adaptation of Joint Position Sense Occurs during and after Sustained Vibration of Antagonistic Muscle Pairs.

Proprioception is critical for the control of many goal-directed activities of daily living. While contributions from skin and joint receptors exist, the muscle spindle is thought to play an important role in allowing accurate judgments of limb position and movement to occur. The discharges elicited from muscle spindles can be degraded by simultaneous agonist-antagonist tendon vibration, causing proprioception to be distorted. Despite this, changes in limb perception that may result from sensory adaptation to this stimulus remain misunderstood. The purpose of this study was, therefore, to investigate short-term proprioceptive adaptation resulting from vibration of antagonistic muscle pairs. We measured elbow joint position sense in 21 healthy young adults while 80 Hz vibration was applied simultaneously to the distal tendons of the elbow flexor and extensor muscles. Matching errors were then analyzed during early and late adaptation phases to assess short-term adaptation to the vibration stimuli. Participants committed significant undershoot errors during the early adaptation phase, but were comparable to baseline measurements during the late adaptation phase. When we removed the vibration stimuli and conducted a second joint position matching task, matching variability increased significantly, and participants committed overshoot errors. These results bring into question the efficacy of simultaneous agonist-antagonist tendon vibration to degrade proprioceptive acuity.

Radial nerve mobilization reduces lateral elbow pain and provides short-term relief in computer users.

Study Design : Prospective Experimental Study.Background : Computer users may be at risk of lateral elbow pain. It is theorized that adverse mechanical tension can arise in the radial nerve with sustained keyboarding due to sustained static work of the elbow extensor muscles. Neural mobilization has been suggested as a potential treatment.Purpose : The purpose of this study was to evaluate the effect of neural mobilization of the radial nerve on a single occasion in terms of its ability to reduce lateral elbow pain.Methods and Analysis : Forty-one computer professionals (Mean age 46.7; S.D. 12.77), who had experienced lateral elbow pain for a mean of 2.87 months were recruited. The participants rated the pain using a verbal, numeric rating scale (NRS). Radial nerve tension was tested using the Upper limb Tension Test (ULTT) for radial nerve in both upper extremities. The radial nerve was mobilized using a series of 8 oscillations and repeated 3 times with a one minute rest in between. The NRS and ULLT were repeated after treatment and the scores compared using a paired t-test by the first author.Results : The mean NRS scores decreased significantly from 5.7 (1.1) to 3.8 (1.4) (p<0.000; t value=8.07).Conclusion : A single session of 3 neural mobilization resulted in a reduction of pain in computer users with lateral elbow pain. A long-term randomized trial is needed to determine the effects sustained over-time.

Selective activation of ipsilateral motor pathways in intact humans.

It has been proposed that ipsilateral motor pathways play a role in the control of ipsilateral movements and recovery of function after injury. However, the extent to which ipsilateral motor pathways are engaged in voluntary activity in intact humans remains largely unknown. Using transcranial magnetic stimulation over the arm representation of the primary motor cortex, we examined ipsilateral motor-evoked potentials (iMEPs) in a proximal arm muscle during increasing levels of unilateral and bilateral isometric force in a sitting position. We demonstrate that iMEP area and amplitude decreased during bilateral contraction of homonymous (elbow flexor) muscles and increased during bilateral contraction of heteronymous (elbow flexor and extensor) muscles compared with a unilateral contraction, regardless of the level of force tested. To further understand the neuronal inputs involved in the bilateral effects, we examined the contribution from neck afferents projecting onto ipsilateral motor pathways. Medial (away from the muscle tested) and lateral (toward the muscle tested) rotation of the head enhanced bilateral iMEP effects from homonymous and heteronymous muscles, respectively. In contrast, head flexion and extension exerted nonspecific bilateral effects on iMEPs. Intracortical inhibition, in the motor cortex where iMEPs originated, showed modulation compatible with the changes in iMEPs. We conclude that ipsilateral projections to proximal arm muscles can be selectively modulated by voluntary contraction of contralateral arm muscles, likely involving circuits mediating asymmetric tonic neck reflexes acting, at least in part, at the cortical level. The pattern of bilateral actions may represent a strategy to engage ipsilateral motor pathways in a motor behavior.

Upper-limb spasticity during the first year after stroke: stroke arm longitudinal study at the University of Gothenburg.

The aims of this study were to describe the prevalence and the severity of upper-limb spasticity during the first year after stroke and to analyze sensorimotor function, pain, reduced range of motion, and sensibility in persons with and without spasticity. This is a longitudinal design with assessments at days 3 and 10; week 4; and mos 3, 6, and 12. A total of 117 patients with first-ever stroke and arm paresis on day 3 were consecutively included. Sixty-five percent were assessed at 12 mos. Upper-limb spasticity was assessed with the Modified Ashworth Scale, and a score of 1 or greater was considered spastic. Sensorimotor function, pain, sensibility, and joint range of motion were assessed with the Fugl-Meyer Assessment. Impairment was defined as a score of less than maximum on the motor and nonmotor domains of the Fugl-Meyer Assessment. Spasticity was present in 25% of the patients at day 3 and in 46% at 12 mos. In most patients with spasticity, the severity increased during the first year after stroke. Spasticity appeared first in the elbow flexors and later in the elbow extensors and the wrist flexors. The patients with spasticity had significantly worse sensorimotor function and more pain, reduced joint range of motion, and reduced sensibility. Spasticity developed in almost half of the assessed patients, and the severity of spasticity increased over time. Because spasticity and impairments related to spasticity, such as pain and limitation in joint range of motion, influence upper extremity function negatively, early identification and treatment of spasticity may be warranted.

Timing of motor cortical stimulation during planar robotic training differentially impacts neuroplasticity in older adults

ObjectiveThe objective was to determine how stimulation timing applied during reaching influenced neuroplasticity related to practice. Older adult participants were studied to increase relevance for stroke rehabilitation and aging. MethodsSixteen participants completed 3 sessions of a reaching intervention with 480 planar robotic movement trials. Sub-threshold, single-pulse transcranial magnetic stimulations (TMS) were delivered during the late reaction time (LRT) period, when muscle activity exceeded a threshold (EMG-triggered), or randomly. Assessments included motor evoked potentials (MEP), amplitude, and direction of supra-threshold TMS-evoked movements and were calculated as change scores from baseline. ResultsThe direction of TMS-evoked movements significantly changed after reaching practice (p<0.05), but was not significantly different between conditions. Movement amplitude changes were significantly different between conditions (p<0.05), with significant increases following the LRT and random conditions. MEP for elbow extensors and flexors, and the shoulder muscle that opposed the practice movement were significantly different between conditions with positive changes following LRT, negative changes following EMG-triggered, and no changes following the random condition. Motor performance including movement time and peak velocity significantly improved following the training but did not differ between conditions. ConclusionsThe responsiveness of the motor cortex to stimulation was affected positively by stimulation during the late motor response period and negatively during the early movement period, when stimulation was combined with robotic reach practice. SignificanceThe sensitivity of the activated motor cortex to additional stimulation is highly dynamic.