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Background and Purpose — Overcoming chronic hemiparesis from a cerebrovascular accident (CVA) can be challenging for many patients, especially after the first 12 months after the CVA. With the use of established motor control theories, the present study investigated electromyogram (EMG)-triggered neuromuscular stimulation and bilateral coordination training. Methods — Twenty-five CVA subjects volunteered to participate in this motor recovery protocol study. Subjects were randomly assigned to 1 of 3 groups: (1) coupled protocol of EMG-triggered stimulation and bilateral movement (n=10); (2) EMG-triggered stimulation and unilateral movement (n=10); or (3) control (n=5). All participants completed 6 hours of rehabilitation during a 2-week period according to group assignments. Motor capabilities of the wrist and fingers were evaluated on the basis of 3 categories of motor tasks in a pretest-posttest control group design. Results — Significant findings for the (1) number of blocks moved in a functional task, (2) chronometric reaction times to initiate movements, and (3) sustained muscle contraction capability all favored the coupled bilateral movement training and EMG-triggered neuromuscular stimulation protocol group. In addition, the unilateral movement/stimulation group exceeded the control group in the number of blocks moved and rapid onset of muscle contractions. Conclusions — This new evidence is convincing in that subjects in the coupled protocol group were able to demonstrate enhanced voluntary motor control across 3 categories of tasks. Chronic hemiparesis decreased considerably in the wrist and fingers as CVA patients expanded their motor repertoire.

The primary purpose of this unique evaluation of cadaveric skeletal geometry was to compare intercondylar notch geometry between males and females. One hundred male skeletons and 100 female skeletons were evaluated. Three indices of notch geometry were calculated from digital photographs of the distal femur: notch width index, notch area index, and notch shape index. Notch shape index for males exceeded that for females (P

Basso, Burgio, Paulin, and Prandoni (2000) claimed evidence for recovery from ideomotor apraxia within the first year post-cerebrovascular accident. However, concerns about the excessive use of paired t tests and incongruous experimental designs challenge the reported findings. The ideomotor apraxia recovery data should be analysed with a completely within-subjects design one-way analysis of variance (ANOVA). Further, the locus of lesion by clinical examination time data should be analysed in a two-way mixed design ANOVA with repeated measures on the three levels of examination time. In addition, circularity assumptions (i.e., composition of the covariance matrices) should be addressed for the repeated measures in the recommended analyses. In a tutorial approach, using the proper experimental designs and statistics, the ideomotor apraxia data were reanalysed. The one-way results support the recovery improvements between the first and second examinations. However, conflict with the original findings was fo...

Essential tremor (ET) is the most common age-related disease leading to abnormal tremulous behaviors in the upper and lower extremities. Non-invasive brain stimulation (NIBS) may be an effective ET therapy by modulating the oscillating network of the brain. The current systematic review and meta-analysis examined the effects of NIBS interventions on tremor symptoms in ET patients. Our comprehensive search identified eight studies that used 1 Hz of rTMS, cTBS, or ctDCS protocols. Twenty total comparisons from the eight qualified studies were statistically synthesized, and the meta-analytic findings revealed that NIBS techniques reduced tremulous behaviors in individuals with ET. Moreover, the four moderator variable analyses demonstrated that the positive therapeutic effects of NIBS appeared across the following subgroups: (a) tremor assessment (clinical test vs. quantitative tremor assessment), (b) stimulation site (cerebellum vs. motor cortex), (c) session number (single session vs. multiple sessions), and (d) sustained positive treatment effect (posttest vs. retention test). This comprehensive systematic review and meta-analysis provided evidence that support positive treatment effects of NIBS techniques on ET motor therapy.

Our meta-analysis and conclusions favoring positive bilateral movement training effects on stroke motor recovery (Cauraugh, Lodha, Naik, & Summers, 2010) have been questioned by Pollock, Morris, van Wijck, Coupar, and Langhorne (2011). Their letter to the editor focuses on three subtle metaanalysis techniques. This reply addresses each concern, confirms our robust meta-analysis, and steadfastly upholds our findings.

The purpose was to investigate force control capabilities in paretic hands during unimanual movements after coupled bimanual movement training and neuromuscular stimulation on impaired muscles. Nineteen chronic stroke participants completed 90 min of rehabilitation per week for six consecutive weeks. Before and after training, volunteers performed unimanual submaximal force control tasks at 5% and 50% of maximum voluntary contraction with their paretic and non-paretic hands. Force control measures included submaximal force production, force variability, accuracy, and regularity. Two major findings on paretic hands after training revealed: (a) greater submaximal force production across force levels and (b) less regular force outputs. Paretic hand control improved after coupled bimanual movement training as evidenced by submaximal force production and force regularity.

Force control deficits are common dysfunctions after a stroke. This review concentrates on various force control variables associated with motor impairments and suggests new approaches to quantifying force control production and modulation. Moreover, related neurophysiological mechanisms were addressed to determine variables that affect force control capabilities. Typically, post stroke force control impairments include: (a) decreased force magnitude and asymmetrical forces between hands, (b) higher task error, (c) greater force variability, (d) increased force regularity, and (e) greater time-lag between muscular forces. Recent advances in force control analyses post stroke indicated less bimanual motor synergies and impaired low-force frequency structure. Brain imaging studies demonstrate possible neurophysiological mechanisms underlying force control impairments: (a) decreased activation in motor areas of the ipsilesional hemisphere, (b) increased activation in secondary motor areas between hemispheres, (c) cerebellum involvement, and (d) relatively greater interhemispheric inhibition from the contralesional hemisphere. Consistent with identifying neurophysiological mechanisms, analyzing bimanual motor synergies as well as low-force frequency structure will advance our understanding of post stroke force control.

Background Neuromuscular stimulation coupled with bilateral movements facilitates functional motor recovery of the upper extremities post stroke. This study investigated electromyography activation patterns during training. The leading question asked: Do EMG activation patterns show rehabilitative effects of coupled bilateral movement training on wrist and fingers extension, elbow extension, and shoulder abduction? Methods Twelve stroke volunteers completed nine hours of coupled bilateral movement training on three sets of joints in their arms. Neuromuscular stimulation on the impaired limb assisted wrist and fingers extension, elbow extension, and shoulder abduction. Mean activation level data were analyzed in a three-way completely within-subjects ANOVA (Training Day × Movement Type × Trial Block: 3 × 3 × 3). Results The analysis revealed three important findings: (a) activation levels in Days 5 and 6 were significantly higher than Days 1 and 2, (b) muscle activation patterns increased across trial blocks, and (c) movements for the shoulder joint/girdle as well as wrist and fingers demonstrated higher activation than the elbow joint. Further analysis indicated that the muscle activation patterns for shoulder abduction were positively associated with force stabilization (ratio of good variability relative to bad variability) during bilateral force production. Conclusions The findings indicate that capability to increase muscle activity during the three joint movements was improved after training. There appears to be higher muscle activation in the primary proximal and distal muscles necessary for motor control improvement.

The purpose of this study was to investigate force variability generated by both the paretic and non-paretic hands during bimanual force control. Nine chronic stroke individuals and nine age-matched individuals with no stroke history performed a force control task with both hands simultaneously. The task involved extending the wrist and fingers at 5%, 25%, and 50% of maximum voluntary contraction. Bimanual and unimanual force variability during bimanual force control was determined by calculating the coefficient of variation. Analyses revealed two main findings: (a) greater bimanual force variability in the stroke group than the control group and (b) increased force variability by the paretic hands during bimanual force control in comparison to the non-paretic hands at the 5% and 25% force production conditions. A primary conclusion is that post stroke bimanual force variability is asymmetrical between hands.

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.

The present study investigated psychophysiological differences in identified sport fans within the context of the biphasic theory of emotion (P. J. Lang, 1985). Forty participants, grouped into three levels of identification with the local university athletic teams, viewed five pictures from each of two categories (team-relevant sport and team-irrelevant sport). Self-identified sport fans rated team-relevant pictures as more pleasant and arousing compared to team-irrelevant pictures. The P3 component of the event-related potential to an irrelevant startle probe was diminished and heart-rate deceleration was enhanced during team-relevant pictures as a function of fan identification level, suggesting that these pictures evoked a motivated attentional state. Neither probe-P3 nor heart rate differed for team-irrelevant pictures. Lastly, increased positivity for slow cortical potentials was evident for team-relevant compared to team-irrelevant pictures, regardless of fan identification level. These results suggest the utility of psychophysiological measures in the study of sport fans, and for other positive emotions as well.

Recently, motor control research has emphasized the planning of macroscopic aspects of control. In object manipulation studies, when participants complete a movement in a comfortable posture, an end-state comfort effect is attained. One explanation for this effect is the precision hypothesis, which states that precision increases when participants are in a comfortable position. This research directly tests the precision hypothesis in two experiments. In Experiment 1, participants picked up a dowel and touched a large or small target on a wall. For the second experiment, the same procedure was followed using a pinpoint target. The probability analyses of the first experiment indicated that the end-state comfort effect was magnified in the small target condition and that the point-of-change effect (Short and Cauraugh, 1997) appeared only when end-state comfort was magnified. Error analyses in Experiment 2 showed that participants were more accurate when in a more comfortable position. The present findings indicate that the precision hypothesis plays a significant role in the end-state comfort effect.

This study investigated force variability and frequency structure below 1 Hz to determine whether coupled bilateral training and neuromuscular stimulation facilitated force control in paretic arms. Fifteen chronic stroke participants received 9 h of coupled bilateral movement training. Unilateral and bilateral force control tasks were administered before and after rehabilitation. Repeated measures ANOVAs were performed on the: (a) coefficient of variation and (b) absolute and relative power below 1 Hz in the paretic hand. Further, a multiple linear regression analysis determined the relationship between the coefficient of variation and frequency power. Three significant rehabilitation findings indicated: (a) reduced force variability across unilateral and bilateral force control conditions, (b) decreased absolute power in 0.09−0.41 Hz and 0.59−1.08 Hz whereas increased relative power in 0.59−1.08 Hz during unilateral force control, and (c) reduced absolute and relative power in 0.09−0.41 Hz that were associated with decreased variability during both unilateral and bilateral force control. Improved force variability in controlling unilateral paretic arms after training was attributed to less power below 0.41 Hz. Reorganization of the force frequency structure appears as a prominent component in force control improvements in paretic arms.

A recent emphasis in motor control research is the planning of macroscopic features and how variables such as efficiency and comfort influence the planning process. This paper extends the work by Rosenbaum and Jorgensen (1992) by further studying the end-state comfort effect. In the first experiment, participants picked up a dowel using an underhand or overhand grip and touched one end to a numbered target on the wall. The height of the #9 target was set at the height of participants' right shoulder. The second experiment involved awkwardness ratings. Participants touched the 14 targets with the dowel as well as with a small dumbbell and the comfort of the end position was rated on a seven-point scale. In the third experiment, participants moved a dumbbell to the targets in the same procedure as the first experiment. Overall, the probability analyses indicated that as the end-state comfort effect was magnified, the sequential effect vanished and a distinct point-of-change effect appeared. Optimization theory and the knowledge model readily explained the phenomena of the end-state comfort effect, the sequential effect, and the point-of-change effect. The present findings indicate that comfort has a powerful influence on the planning of motor performance.

Bimanual movement disorders are common dysfunctions post stroke. This stroke study investigated bimanual force control capabilities to determine the effect of coupled bimanual movement training on bimanual coordination and motor synergy. Stroke participants (N = 11) completed three bimanual force control tasks at 5, 25, and 50 % of maximum voluntary contraction before and after coupled bimanual movement training. Root mean square error (RMSE), approximate entropy, correlation, and bimanual motor synergy were analyzed in two-way completely within-subjects ANOVAs (Test Session × Force Level: 2 × 3). Multiple linear regression analysis determined the relationship between RMSE and other force control measures. The analyses revealed three important findings: (1) RMSE decreased from baseline to posttest (2) negative correlation (e.g., error compensation) and bimanual motor synergy increased at 25 and 50 % after rehabilitation, and (3) increased bimanual motor synergy was strongly associated with decreased RMSE after training. The findings indicate that coupled bimanual movement training improved force control performance, bimanual coordination, and motor synergies. Indeed, the present findings extend bimanual motor synergies as a meaningful indicator for estimating task performance improvements. Finally, bimanual force control is a valid outcome measure in quantifying progress toward motor recovery post stroke.

Simulated tennis playing situations were created for the laboratory testing of visual search patterns, anticipation, reactions, and movements to compare male and female high-level and beginning players. Of particular interest was the degree to which each measure would differentiate the groups. Participants were highly-rated university players (N-30) and students enrolled in a beginning tennis class (N = 30). Under one testing condition, visual search patterns were recorded as they viewed filmed opponents serve (60 trials) and hit ground strokes (60 trials). Also recorded was anticipation accuracy and speed of the intended type and location of serves and the intended placement of ground strokes. In other testing, execution of a split step was followed by moving rapidly to the comet location for a simulated stroke in response to a series of light cues. Reaction and movement times were recorded. Discrimination analysis revealed that experts and beginners were most differentiated due to fixations on ...

The accuracy and variability of a sustained low-level force contraction (2% of maximum voluntary contraction) was measured while participants viewed unpleasant, pleasant, and neutral images during a feedback occluded force control task. Exposure to pleasant and unpleasant images led to a relative increase in force production but did not alter the variability of force production compared to conditions in which participants viewed neutral images. Findings are discussed with respect to prior work, emphasizing arousal specific changes that emerge at low target force levels.

Quantifying the accuracy and consistency of human motor performance has often involved calculating various error score measures of an individual's performance across a block of trials. Traditionally, error score measures have been used for tasks in which performance can vary in only one dimension. However, recent studies have used these error measures with more complex tasks, in which performance may deviate on the horizontal and vertical axes of a two-dimensional surface. This article examines the use of these one-dimen- sional task error measures for performance on two-dimensional tasks, with special attention to a recent article by Singer, Cauraugh, Murphey, Chen, and Lidor (1991). We show that using one-dimensional e m r scores to assess perfor- mance on a two-dimensional task may yield results that are arbitrary and thus difficult to interpret in a meaningful way.

The trainability of anticipatory skills for tennis was assessed. Subjects (N = 34) from a beginning/intermediate tennis class were randomly assigned to either a mental quickness or a physical quickness (control) training group. They were tested in three laboratory tennis simulation tasks and three on-court tasks (serves, ground strokes, and volleys) 1 week before and after the 3-week quickness training program. Quickness Training × Gender × Test Session (2 × 2 × 2) ANOVAs with repeated measures on the third factor were conducted. For the laboratory tasks, the mental quickness group made faster decisions in reaction to serves, exhibited faster anticipation times, and showed improved accuracy in predicting serve type and location. No improvements in accuracy were found for the physical quickness group. For filmed match-play situations, the mental quickness group improved reaction times with training and committed fewer response errors. Implications for the design of instructional methods used in dynamic and fast-paced sports are discussed.

Objective: We investigated the effect of long-term practice on motor improvements in chronic stroke patients. Design: Randomized parallel group controlled study. Setting: Motor Behavior Laboratory, University of Florida. Subjects: Eighteen individuals who experienced a stroke more than nine months prior to enrolling. Interventions: The treatment interventions were bilateral arm movements coupled with active neuromuscular stimulation on the impaired arm for both practice duration groups. The short-term group received one treatment protocol, whereas, over 16 months, the long-term practice group completed 10 treatment protocols. All protocol sessions were 6 hours long (90 minutes 1 day/week/4 weeks) and were separated by 22 days. Main outcome measures: Repeated data collection on three primary outcome measures (i.e. Box and Block test, fractionated reaction times, and sustained force production) evaluated motor capabilities across rehabilitation times. Results: Mixed design ANOVAs (Group × Retention Test: 2 × 4; Group × Retention Test × Arm Condition: 2 × 4 × 2) revealed improved motor capabilities for the long-term practice duration group on each primary measure. At the 16-month delayed retention test, when compared to the short-term group, the long-term group demonstrated: (a) more blocks moved (43 v 32), (b) faster premotor reaction times (158 v 208 ms), and (c) higher force production (75 v 45 N). Conclusion: Sixty hours of rehabilitation over 16 months provided by various bilateral arm movements and coupled active stimulation improved motor capabilities in chronic stroke.

Objective This study determined the nature of bimanual deficits during visually-guided isometric force production in chronic stroke. Methods Stroke survivors and age-matched controls performed bimanual isometric wrist/finger extension contractions for 20 s to target submaximal force levels. Force asymmetry was indexed by the proportion of force contributed by the impaired hand to total force. Force coordination was determined by computing time-series cross-correlations and time-lag between force outputs of both hands. Results The stroke group demonstrated greater asymmetry and reduced coordination in force produced by each hand. The extent of asymmetry in the force magnitude remained constant across the three submaximal force levels in both groups. Bimanual force coordination increased at higher forces in controls but not in stroke. Finally, the less-impaired hand forces time-lagged the impaired hand. Conclusions Bimanual motor impairments in chronic stroke are characterized by increased asymmetry and reduced coordination between individual hand forces. Distinct control mechanisms are involved in the production and coordination of forces following stroke. Significance An implication involves rehabilitation protocols that emphasize bimanual coordination for training the hands to produce symmetric forces that are temporally coordinated.

The effectiveness of three learning strategies on achievement was compared in the learning and performing of a self-paced motor task. More specifically, investigated was the influence of (a) an awareness strategy (to consciously attend to the act and to what one is doing during execution); (b) a nonawareness strategy (to preplan the movement and perform the task without conscious attention to it; “to just do it”); (c) the Five-Step Approach (to systematically ready oneself, image the act, focus attention on a cue, execute without thought, and evaluate the act and the previous steps); and (d) a control condition (to use one’s own approach). Subjects (N = 72) received 250 trials to master a computer-managed ball-throwing task, and 50 more in a dual-task situation. The Five-Step Approach and nonawareness strategies led to the highest achievement, and the three strategies resulted in less radial error in comparison to the control condition.

Objective: This study determined the variability and regularity of force production in impaired upper extremities of chronic stroke survivors. Two hypotheses included: (1) stroke will increase the variability and regularity of force output in comparison to age-matched controls and (2) degree of motor impairments will be positively correlated with the variability and regularity of force output. Methods: Nine chronic stroke and nine age-matched controls performed unimanual isometric wrist and finger extension movements for 20 s to three different target force levels. Force output was indexed by magnitude, accuracy, variability, and regularity. Stroke motor impairment levels were determined by Fugl-Meyer upper extremity assessment. Results: The stroke group demonstrated increased variability and regularity of the force output. Further, motor impairments scaled with increase in variability and regularity of force output. Conclusions: The variability and regularity of force differentiated isometric contractions performed by chronic stroke survivors from age-matched controls. Moreover, in clinical settings an objective assessment of force control on variability and regularity appears to be most meaningful at 25% of MVC. Significance: Increased variability contributes to reduced steadiness in force output. Increased regularity characterizes the adaptability losses in motor capabilities following stroke. This knowledge may facilitate planning and evaluating rehabilitation protocols.

In the present study, we examined whether preparing motor responses under different emotional conditions alters motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation delivered to the motor cortex. Analyses revealed three findings: (1) Reaction times were expedited during exposure to unpleasant images, as compared with pleasant and neutral images; (2) force amplitude was greater during exposure to unpleasant images, as compared with pleasant and neutral images; and (3) MEPs were larger while participants viewed unpleasant images, as compared with neutral images. Hence, coupling the preparation of motor responses with the viewing of emotional images led to arousal-driven changes in corticospinal motor tract excitability, whereas movement speed and force production varied as a function of emotional valence. These findings demonstrate that the effects of emotion on the motor system manifest at varying sensitivity levels across behavioral and neurophysiological measures. Moreover, they validate the action readiness component of emotional experience by demonstrating that emotional states influence the execution of future movements but, alone, do not lead to overt movement.

Despite the high incidence of lateral ankle sprains, the issue about whether postural control is impaired after acute or chronic injury is still unresolved. In addition, the literature is unclear if balance training, a commonly prescribed intervention, improves postural control after a history of lateral ankle trauma. Purpose: To conduct a meta-analysis on studies reporting the effects of lateral ankle trauma on postural control and how balance training affects postural control after acute and chronic lateral ankle trauma cumulatively and separately as moderating variables. Methods: Thirty-seven postural control studies qualified for inclusion in the meta-analysis. Twenty-five studies investigated postural control independent of an intervention, and 15 studies administered balance-training interventions. Separate analyses on the two types of studies calculated Hedges' g individual effect sizes (ES). Further, we explored moderating variables for both the postural stability and the intervention studies. Results: A significant cumulative effect size (ES) indicated that postural stability is impaired after a history of ankle injury (ES = 0.492, P < 0.0001). Moderator analysis revealed that both acute and chronic lateral ankle trauma negatively affected balance: a) acute: ES = 0.419, P < 0.0001, and b chronic, ES = 0.570, P < 0.0001. A third meta-analysis showed that balance training improves postural control (ES = -0.857, P < 0.0001). In addition, moderator variables indicated large ES for both types of ankle trauma. Conclusions: Postural control impairments are present in patients with a history of lateral ankle trauma. However, clinicians should exercise caution when using the uninjured contralateral limb as a reference of normal postural control. In addition, balance training improves postural control scores after both acute and lateral ankle trauma. However, further research should determine the optimal dosage, intensity, type of training, and a risk reduction/preventative effect associated with balance training after both acute and chronic ankle trauma.

The purpose of this investigation was to compare dynamic postural control and mechanical ankle stability among patients with and without chronic ankle instability (CAI) and controls. Seventy-two subjects were divided equally into three groups: uninjured controls, people with previous ankle injury but without CAI, and people with CAI. Subjects completed a single-leg hop-stabilization task, and then had an anterior drawer test and lateral ankle radiograph performed bilaterally. The dynamic postural stability index was calculated from the ground reaction forces of the single-leg hop-stabilization task. Ankle joint stiffness (N/m) was measured with an instrumented arthrometer during the anterior drawer test, and fibula position was assessed from the radiographic image. Patients with previous ankle injuries but without CAI demonstrated higher frontal plane dynamic postural stability scores than both the uninjured control and CAI groups (P

Research indicates that balance is impaired in the involved limb following an ankle injury. However, bilateral balance impairments are a viable reason for previous non-significant findings between involved and uninvolved limbs. The purpose of this investigation was to conduct a meta-analysis on studies reporting the effects of lateral ankle trauma on balance of the involved and uninvolved limb after acute ankle injury and chronic ankle instability. Twelve studies qualified for inclusion and assessed static balance for both the involved and uninvolved limbs post-injury and a control group. Meta-analyses calculated standardized mean difference effects and explored moderating variables for the involved and uninvolved limbs relative to controls. A significant cumulative effect size (ES=0.448, p

Background—The current treatment intervention study determined the effect of coupled bilateral training (i.e., bilateral movements and EMG-triggered neuromuscular stimulation) and resistive load (mass) on upper extremity motor recovery in chronic stroke. Methods—Thirty chronic stroke subjects were randomly assigned to one of three behavioral treatment groups and completed 6 hours of rehabilitation in 4 days: (1) coupled bilateral training with a load on the unimpaired hand, (2) coupled bilateral training with no load on the unimpaired hand, and (3) control (no stimulation assistance or load). Results—Separate mixed design ANOVAs revealed improved motor capabilities by the coupled bilateral groups. From the pretest to the posttest, both the coupled bilateral no load and load groups moved a higher number of blocks and demonstrated more regularity in the sustained contraction task. Faster motor reaction times across test sessions for the coupled bilateral load group provided additional evidence for improved motor capabilities. Conclusions—Together these behavioral findings lend support to the contribution of coupled bilateral training with a load on the unimpaired arm to improved motor capabilities on the impaired arm. This evidence supports a neural explanation in that simultaneously moving both limbs during stroke rehabilitation training appears to activate balanced interhemispheric interactions while an extra load on the unimpaired limb provides stability to the system.

This study addressed the nature of potential auditory and visual distractors and their influence on the learning of two motor tasks. The extent to which an attentional-focus training program could be used to overcome external and unpredictable distractor occurrences was determined. Eight treatment condi- tions were created by crossing two levels of attentional training and four levels of distractors (noise, light, noise and light, and no distractor). Ten subjects were randomly assigned to each treatment condition, and two target-throwing tasks were performed with the nondominant hand. Thrget accuracy for the 80 trials was recorded by a microcomputer. The separate Attentional 'Itain- ing x Distractor x nial Block (2 x 4 x 6) mixed-design analyses revealed four significant interactions. Overall, the data indicated that the attentional-focus training group was more accurate and consistent than the no-attentional- training group early and later in learning. In addition, distractor groups that experienced atte...

The temporal constraints of tennis serves were manipulated as a percentage of maximum service velocity. The velocity conditions were 50, 60, 70, 80, and 90%. Elite tennis players ( N = 15) completed 10 serves at each velocity. Three error measures (total variability, constant error, and variable error) were analyzed separately for target accuracy, accuracy of ball velocity, and proportional error in velocity. Significant total variability and variable error were found for proportional error in velocity. Both measures showed improved performance as ball velocity increased from 70% to 90%.

We aimed to clarify the relation between affective valence and motivational direction by specifying how central and peripheral components of extension movements are altered according to specific unpleasant affective states. As predicted, premotor reaction time was quicker for extension movements initiated during exposure to attack than for extension movements initiated during exposure to all other valence categories (mutilation, erotic couples, opposite-sex nudes, neutral humans, household objects, blank). Exposure to erotic couples and mutilations yielded greater peak force than exposure to images of attack, neutral humans, and household objects. Finally, motor reaction time and peak electromyographic amplitude were not altered by valence. These findings indicate that unpleasant states do not unilaterally prime withdrawal movements, and that the quick execution of extension movements during exposure to threatening images is due to rapid premotor, rather than motor, reaction time. Collectively, our findings support the call for dissociating motivational direction and affective valence.

Incomplete spinal cord injury (ISCI) frequently disrupts afferent and efferent neural pathways underlying co-requisite voluntary and involuntary muscle activation required for functional standing and walking. To understand involuntary postural control mechanisms necessary for standing, we compared eight individuals with ISCI to eight controls with no impairment. The aim of this study was to investigate anticipatory and reactive balance responses in individuals with ISCI. The ability to adapt to changes in balance conditions was assessed by monitoring automatic postural responses (APRs) during a series of expected and unexpected changes in perturbation direction (backward translation versus toes-up rotation). Both groups were able to modulate appropriately within one or two trials following an unexpected change in condition. Onset times of anterior tibialis and medial gastrocnemius (MG) were significantly slower in the ISCI group during expected and unexpected conditions. These findings demonstrate that persons with mild to moderate lower extremity sensorimotor deficits are able to generate and adapt APRs to a rapid and unexpected contextual change during a simple standing balance task.

Background: The purpose was to determine the cumulative longitudinal effects of upper extremity distributed practice with variable treatment protocols involving EMG-triggered neuromuscular stimulation and coupled bilateral movements. Methods: Sixteen chronic stroke subjects were randomly selected to complete 5 effective upper extremity treatment protocols over 12 months. The subjects were randomly assigned to 1 of 2 treatment orders. Consistent across the orders and protocols, the participants completed 90 min of training per day for 4 days during separate 2-week rehabilitation periods. Results: Data for the 5 primary outcome measures were analyzed in separate mixed design ANOVAs (treatment order × test session: 2 × 6). The analyses revealed distinct cumulative treatment evidence later in training in comparison to the baseline motor capabilities: (1) higher number of blocks moved; (2) higher percentage of blocks moved by the impaired hand; (3) faster motor reaction time (peripheral component), and (4) faster total reaction time. Conclusions: These chronic stroke patients displayed robust cumulative motor improvement effects from the longitudinally distributed practice of active neuromuscular stimulation and coupled bilateral movements.

Evidence indicates that experience-dependent cortical plasticity underlies post-stroke motor recovery of the impaired upper extremity. Motor skill learning in neurologically intact individuals is thought to involve the primary motor cortex, and the majority of studies in the animal literature have studied changes in the primary sensorimotor cortex with motor rehabilitation. Whether changes in engagement in the sensorimotor cortex occur in humans after stroke currently is an area of much interest. The present study conducted a meta-analysis on stroke studies examining changes in neural representations following therapy specifically targeting the upper extremity to determine if rehabilitation-related motor recovery is associated with neural plasticity in the sensorimotor cortex of the lesioned hemisphere. Twenty-eight studies investigating upper extremity neural representations (e.g., TMS, fMRI, PET, or SPECT) were identified, and 13 met inclusion criteria as upper extremity intervention training studies. Common outcome variables representing changes in the primary motor and sensorimotor cortices were used in calculating standardized effect sizes for each study. The primary fixed effects model meta-analysis revealed a large overall effect size (E.S. = 0.84, S.D. = 0.15, 95% C.I. = 0.76 – 0.93). Moreover, a fail-safe analysis indicated that 42 null effect studies would be necessary to lower the overall effect size to an insignificant level. These results indicate that neural changes in the sensorimotor cortex of the lesioned hemisphere accompany functional paretic upper extremity motor gains achieved with targeted rehabilitation interventions.

Understanding the emotion-movement relationship is crucial to the development of motor theory and movement rehabilitation recommendations for a wide range of diseases and injuries that involve motor impairment. Behaviorally, when movements are executed following exposure to emotional stimuli, evidence suggests that active defensive circuitry results in faster but more variable voluntary movements. However, each of the existing protocols has involved movement execution following the offset of anxiety or emotion eliciting stimuli. The specific aim of this study, therefore, was to determine whether the continued exposure to emotional stimuli would alter the magnitude and variability of a sustained motor contraction. During the presentation of pleasant, unpleasant, neutral, and blank images, participants (N=45) were instructed to respond to the onset of an auditory stimulus by initiating and then sustaining a maximal bimanual isometric contraction of the wrist and finger extensor muscles against two independent load cells (left/right limb). Corroborating previous evidence and supporting hypothesis 1, findings indicated that exposure to unpleasant images lead to an increase in mean force production. Variability of movement, however, did not vary as a function of affective context. These findings indicate that continued exposure to unpleasant stimuli magnifies the force production of a sustained voluntary movement, without sacrificing the variability of that contraction. Mechanism driven open and closed loop explanations are offered for these phenomena, implications are addressed, and future directions are discussed.

The purpose of this investigation was to examine lower-extremity biomechanical differences between prepubescent and postpubescent female recreational athletes during three drop jump-landing sequences (static landing, vertical landing, and lateral landing) to determine whether maturation influenced injury risk.Sixteen recreationally active postpubescent women (18-25 yr of age) and 16 recreationally active girls (8-11 yr of age) participated in this study. High-speed three-dimensional videography and force plate data were recorded for each subject's performance of the landing tasks and an inverse dynamics procedure was used to estimate knee joint resultant moments and forces. Kinematic and kinetic dependent variables were analyzed in three separate mixed-design 2 x 3 (maturation level x landing sequence) repeated measures multivariate analysis of variance.Statistical analyses indicated significant maturation level x landing sequence interactions for postpubescent participants who exhibited reduced knee flexion (4.5 degrees ) at initial contact, increased mediolateral knee joint forces [prepubescent: -0.63 +/- 0.21 N.(kg. radicalLH)(-1), postpubescent: 0.55 +/- 0.21 N.(kg. radicalLH)(-1)], and reduced knee extensor moments [prepubescent: -0.0124 +/- 0.001 N.m.(kg.BH. radicalLH)(-1), postpubescent: -0.0079 +/- 0.001 N.m.(kg.BH. radicalLH)(-1)] compared with their prepubescent counterparts.These findings suggest that developmental changes influence knee mechanics during landings in female athletes and highlight the need to examine multiple landing patterns when investigating landing strategies.

Motor improvements in chronic stroke recovery accrue from coupled protocols of bilateral movements and active neuromuscular stimulation. This experiment investigated coupled protocols and within-limb transfer between distal and proximal joint combinations. The leading question focused on within-limb transfer of coupled protocols on distal joints to a bimanual aiming task that involved proximal joints. Twenty-six volunteers completed one of three motor recovery protocols according to group assignments: (1) coupled bilateral involved concurrent wrist/finger movements on the unimpaired limb coupled with active stimulation on the impaired limb; (2) unilateral/active stimulation involved neuromuscular electromyogram-triggered stimulation on the impaired wrist/fingers; and (3) no protocol (control group). During the pretest and posttest, subjects performed transverse plane target aiming movements (29 cm) with vision available. The coupled bilateral group showed positive intralimb transfer post-treatment when both arms moved simultaneously. During the posttest, the coupled bilateral group displayed improved movement time, higher peak limb velocity, less variability in peak velocity, and less percentage of total movement time in the deceleration phase than during the pretest. The evidence confirms that within-limb transfer from distal joint training to proximal joint combinations is viable and generalizable in chronic stroke rehabilitation. Moreover, these intralimb transfer findings extend the evidence favoring motor improvements for coupled bilateral protocols during chronic stroke.

Identifying effective rehabilitation interventions founded on sound theoretical and neurophysiological bases should decrease the prevalence of motor disabilities and chronic hemiparesis. This article addresses two theoretically sound behavioral interventions: (a) active neuromuscular stimulation on the impaired upper extremity and (b) coupled bilateral coordination training (i.e., mirrored movements on the less impaired limb combined with active stimulation on the impaired limb). The series of stroke motor recovery experiments currently reviewed clearly indicate that sensorimotor integration theory and bimanual coordination theory are viable candidates for directing behavioral rehabilitation approaches. Indeed, the reported evidence clearly supports activity dependent neural plasticity for progress toward stroke motor recovery.

Debate persists about the effectiveness of poststroke behavioral interventions for progress toward motor recovery. The current meta-analysis assessed the effect of electromyogram (EMG)-triggered neuromuscular stimulation on arm and hand functions. Computer searches of PubMed and Cochran databases, as well as hand searches of reference lists identified seven EMG-triggered neuromuscular stimulation studies. Outcome measures focused on arm and hand motor capability functions. In addition, the quality of each study was rated on three guidelines: randomization, double blind, and dropouts. After adjusting data for consistency in the arm/hand outcome measures and to avoid bias, five active stimulation studies were included in the analysis. Rehabilitation treatment in each study focused on wrist extension. The total number of individuals in the treatment groups was 47 whereas the control groups had 39 subjects. The meta-analysis revealed a significant overall mean effect size (delta=0.82, S.D.=0.59). A homogeneity test indicated that the pooled standardized effect sizes estimated the same treatment effect. A fail-safe test for null effect findings revealed that 15 studies were required to reduce the large effect (0.82) to a small effect (0.20). These improved wrist extension motor capabilities findings support EMG-triggered neuromuscular stimulation as an effective poststroke protocol.

Background and Purpose —After stroke, many individuals have chronic unilateral motor dysfunction in the upper extremity that severely limits their functional movement control. The purpose of this study was to determine the effect of electromyography-triggered neuromuscular electrical stimulation on the wrist and finger extension muscles in individuals who had a stroke ≥1 year earlier. Methods —Eleven individuals volunteered to participate and were randomly assigned to either the electromyography-triggered neuromuscular stimulation experimental group (7 subjects) or the control group (4 subjects). After completing a pretest involving 5 motor capability tests, the poststroke subjects completed 12 treatment sessions (30 minutes each) according to group assignments. Once the control subjects completed 12 sessions attempting wrist and finger extension without any external assistance and were posttested, they were then given 12 sessions of the rehabilitation treatment. Results —The Box and Block test and the force-generation task (sustained muscular contraction) revealed significant findings ( P Conclusions —Two lines of evidence clearly support the use of the electromyography-triggered neuromuscular electrical stimulation treatment to rehabilitate wrist and finger extension movements of hemiparetic individuals ≥1 year after stroke. The treatment program decreased motor dysfunction and improved the motor capabilities in this group of poststroke individuals.

This study analyzed the ability of an in-shoe plantar pressure measurement system to provide repeatable measurements of postural sway data for both healthy and clinical patients. Each participant's in-shoe pressure data were recorded for three trials during each test session during quiet stance. Healthy individuals (n=9) participated on three consecutive days while clinical participants (n=5) were tested on one day. Nine response variables were measured to assess their postural stability. Intra-subject measures were evaluated using the Kerlinger reliability procedure. Values provided directly by the Parotec System® for a single day of testing yielded the following average coefficients: r = 0.95 (left), r = 0.97 (right) with mean coefficient values from the three day tests of: r = 0.98 (left), r = 0.98 (right). Variables calculated from raw data on a single day produced mean coefficients of: r = 0.77 (left), r = 0.76 (right) and over three days of: r = 0.65 (left), r =0.66 (right). The ability to record highly reproducible data of postural sway parameters should assist clinicians to treat patients more confidently for balance deficiencies.

Individuals with Parkinson's disease have difficulty initiating and performing complex, sequential movements. Practice generally leads to faster initiation and execution of movements in healthy adults, however, whether practice similarly improves motor performance in patients with Parkinson's disease remains controversial. To assess the effects of practice on motor performance, patients with Parkinson's disease and control subjects practiced two, rapid arm-reaching tasks with different levels of movement complexity for 120 trials each over 2 days. Response programming was studied by analyzing the overall reaction time latency of each movement and its fractionated sub-components, premotor and motor time. Practice effects were investigated by comparing pretest performance to immediate and delayed retention test performances (10-min and 48-h rest intervals, respectively). Both patients with Parkinson's disease and control subjects improved speeded performance of sequential targeting tasks by practice and retained the improvement across both retention test intervals. Finding a learning effect for persons with Parkinson's disease supports practice as an effective rehabilitation strategy to improve motor performance of specific tasks for patients with Parkinson's disease.

Background: This work is part of an ongoing effort to introduce an innovative medical teaching technique to assist the efficient acquisition of surgical hand skills required to perform an inguinal hernia repair with a McVay technique. The purpose was to determine the effect of expert cognitive modeling, auditory elaboration, and split-screen video analysis on the surgical hand movements required while performing inguinal hernia surgery on cadavers. Purpose: Six surgical residents were videotaped performing a McVay procedure inguinal hernia in a pretest-posttest control group design. The experimental group received expert cognitive modeling, auditory elaboration, and split-screen analysis after the pretest. Results: A distinct advantage for surgical instrument control and manipulation was found for the experimental group on the posttest surgeries. Less time was required to perform the operation, and more purposeful movements were exhibited by the experimental group. Conclusion: The treatment condition favored mindfulness learning of the McVay technique for an inguinal hernia repair.

Gait in Parkinson's disease is characterised by slowed velocity; shuffling, small steps; and absent arm swing. Drug therapy intervention is beneficial in improving mobility, though with prolonged use its effects may diminish. The purpose of this study was to examine whether Parkinsonian patients could improve their gait patterns in response to five instructional sets: natural walking; walking while deliberately swinging the arms; walking with large steps; fast walking; and walking while counting aloud. Eight subjects with idiopathic Parkinson's disease and eight age matched control subjects were tested using motion analysis. The findings indicated that parkinsonian patients followed the instructions which immediately altered a series of single walking variables. Simultaneously, automatically activated changes occurred in other gait variables producing more normal gait. The instructional set is a strategy which can aid normalisation of Parkinsonian gait although its benefits may depend on the stage of disease progression and the degree of attention to the instructions.

Increased force variability constitutes a hallmark of arm disabilities following stroke. Force variability is related to the modulation of force below 1 Hz in healthy young and older adults. However, whether the increased force variability observed post stroke is related to the modulation of force below 1 Hz remains unknown. Thus, the purpose of this study was to compare force modulation below 1 Hz in chronic stroke and age-matched healthy individuals. Both stroke and control individuals (N = 26) performed an isometric grip task to submaximal force levels. Coefficient of variation quantified force variability, and power spectrum density of force quantified force modulation below 1 Hz with a high resolution (0.07 Hz). Analyses indicated that force variability was greater for the stroke group compared with to healthy controls and for the paretic hand compared with the non-paretic hand. Force modulation below 1 Hz differentiated the stroke individuals and healthy controls, as well as the paretic and non-paretic hands. Specifically, stroke individuals (paretic hand) exhibited greater power ~0.2 Hz (0.07-0.35 Hz) and lesser power ~0.6 Hz (0.49-0.77 Hz) compared to healthy controls (non-dominant hand). Similarly, the paretic hand exhibited greater power ~0.2 Hz, and lesser power ~0.6 Hz than the non-paretic hand. Moreover, variability of force was strongly predicted from the modulation of specific frequencies below 1 Hz (R(2) = 0.80). Together, these findings indicate that the modulation of force below 1 Hz provides significant insight into changes in motor control after stroke.

The effects of two types of bandwidth (BW) knowledge of results (KR) were investigated on the acquisition and immediate retention of a timing task. Traditional and reversed BW KR groups were compared with two yoked control groups. Forty-eight randomly assigned subjects completed 60 acquisition trials and 20 no-KR retention trials. Acquisition analysis indicated a greater timing accuracy for the traditional BW group in comparison to the reversed BW group. During retention, less absolute constant error was found for both BW groups than for their yoked controls. Absolute performance changes were analyzed to further differentiate the contributions of quantitative and qualitative KR available in both types of BW conditions. This analysis revealed a significant KR x Trial Type interaction. Reliable changes in performance were observed after quantitative trials for the traditional BW group, whereas for the reversed BW group, reliable changes were observed after qualitative trials. This reversed BW group finding, along with the retention accuracy findings, indicated that the qualitative information was used to learn the timing task.