Physical therapy intervention for breast symptoms in lactating women: a randomized controlled trial.

BACKGROUND: Therapeutic ultrasound, education, and massage are the most common physical therapy interventions provided to mothers with breast symptoms. However, there is insufficient evidence on the effectiveness of the combination of these interventions. This study aimed to explore the effects of the combination of therapeutic ultrasound, education, and massage on breast symptoms in lactating women. METHODS: This study was a single-blind randomized controlled trial. Postpartum lactating women aged from 21 to 45 with breast symptoms were recruited and randomly allocated to one of three groups (ultrasound group, sham group, and usual care group). The severity of breast symptoms (pain, redness, lump, general malaise), breast engorgement, breast hardness, body temperature, breast temperature, and milk volume were assessed at baseline (T1), immediately post-intervention (T2), and at 3 months following baseline (T3). RESULTS: A total of 37 participants were included in the study (ultrasound group n = 12; sham group n = 12; usual care n = 13). The severity of breast symptoms (i.e., pain, lump, and general malaise) as well as breast engorgement, were significantly improved in the ultrasound group at T2 when compared to T1, and these improvements were sustained at T3. The severity of breast engorgement was significantly lower in the ultrasound group when compared to the usual care group at T2. However, no statistically significant differences were found between the ultrasound and sham groups for all outcomes at any assessment time points. CONCLUSIONS: Physical therapy interventions may be beneficial in relieving breast symptoms in lactating women. Larger randomized controlled trials are needed to confirm the findings of this study. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04569136); Date of registration: 29/09/2020.

Dancers with non-specific low back pain have less lumbar movement smoothness than healthy dancers.

BACKGROUND: Ballet is a highly technical and physically demanding dance form involving extensive end-range lumbar movements and emphasizing movement smoothness and gracefulness. A high prevalence of non-specific low back pain (LBP) is found in ballet dancers, which may lead to poor controlled movement and possible pain occurrence and reoccurrence. The power spectral entropy of time-series acceleration is a useful indicator of random uncertainty information, and a lower value indicates a greater smoothness or regularity. The current study thus applied a power spectral entropy method to analyze the movement smoothness in lumbar flexion and extension in healthy dancers and dancers with LBP, respectively. METHOD: A total of 40 female ballet dancers (23 in the LBP group and 17 in the control group) were recruited in the study. Repetitive end-range lumbar flexion and extension tasks were performed and the kinematic data were collected using a motion capture system. The power spectral entropy of the time-series acceleration of the lumbar movements was calculated in the anterior-posterior (AP), medial-lateral (ML), vertical (VT), and three-directional (3D) vectors. The entropy data were then used to conduct receiver operating characteristic curve analyses to evaluate the overall distinguishing performance and thus cutoff value, sensitivity, specificity, and area under the curve (AUC) were calculated. RESULTS: The power spectral entropy was significantly higher in the LBP group than the control group in the 3D vector in both lumbar flexion and lumber extension (flexion: p = 0.005; extension: p < 0.001). In lumbar extension, the AUC in the 3D vector was 0.807. In other words, the entropy provides an 80.7% probability of distinguishing between the two groups (i.e., LBP and control) correctly. The optimal cutoff entropy value was 0.5806 and yielded a sensitivity of 75% and specificity of 73.3%. In lumbar flexion, the AUC in the 3D vector was 0.777, and hence the entropy provided a probability of 77.7% of distinguishing between the two groups correctly. The optimal cutoff value was 0.5649 and yielded a sensitivity of 90% and a specificity of 73.3%. CONCLUSIONS: The LBP group showed significantly lower lumbar movement smoothness than the control group. The lumbar movement smoothness in the 3D vector had a high AUC and thus provided a high differentiating capacity between the two groups. It may therefore be potentially applied in clinical contexts to screen dancers with a high risk of LBP.

Factors associated with utilization of physical therapy services during pregnancy and after childbirth.

Objective: To explore demographic and clinical factors associated with utilization of antepartum/postpartum physical therapy. Methods: This is a secondary analysis of a cross-sectional survey of 298 women who were receiving or had received obstetric care at a medical center in southern Taiwan. Data were collected between May 2021 and May 2022 using an online questionnaire, which included demographic, medical, and obstetric details, the symptom severity questionnaires, management strategies, and experience and perception about physical therapy. Descriptive statistics, independent t-test, chi-square analysis and multivariate logistic regression model were used to analyze data. Results: Among 298 respondents, 190 (63.8%) were pregnant and 108 (36.2%) were postpartum. Thirteen percent of pregnant participants and 27% of postpartum participants had received physical therapy during and/or after childbirth. Multivariate analyses showed that being postpartum, having an associate degree and below, and experiencing depressive symptoms were significantly associated with an increased utilization of physical therapy (postpartum: OR = 3.039, 95% CI = 1.530, 6.035; associate degree and below: OR = 2.521, 95% CI = 1.007, 6.316; depressive symptoms: OR = 3.606, 95% CI = 1.067, 12.185). The odds of utilizing physical therapy decreased with age (OR = 0.935, 95% CI = 0.874, 1.000). Conclusions: Individual factors, such as age, education level, pregnancy status, and experience of depressive symptoms, have a significant association with utilization of antepartum/postpartum physical therapy and should be considered when developing obstetric care pathways to optimize clinical and healthcare utilization outcomes.

A novel home-based rehabilitative knee brace system is a viable option for postoperative rehabilitation after anterior cruciate ligament reconstruction: a report of 15 cases.

PURPOSE: To investigate the functional outcomes for patients who used a novel home-based rehabilitative system during the postoperative period after anterior cruciate ligament (ACL) reconstructions. METHODS: Patients undergoing ACL reconstruction surgeries were prospectively enrolled. A home-based rehabilitation system, which is composed of a knee brace with a motion tracker, a mobile app, and a web portal, was applied. Patients could complete the rehabilitation exercise through the audio guidance and the real-time tracking system which displayed the achieved motions on the user interface of the app. Feedbacks from the patients, including the International Knee Documentation Committee (IKDC) scores, were collected and uploaded to the web portal. Each patient would meet a specialized physical therapist face-to-face once a month. At postoperative 6 months, every patient received a GNRB arthrometer examination and a Cybex isokinetic dynamometer examination. RESULTS: A total of 15 patients (10 males and 5 females) were enrolled and followed for at least 6 months. The mean time of return to full knee extension was 1.5 months. The mean difference in laxity measured by GNRB arthrometer at 134 N significantly improved at postoperative 6 months (1.8 ± 1.6 mm) compared to that measured preoperatively (3.4 ± 1.9 mm) (p = 0.024). The peak torques of flexor and extensor muscles measured by Cybex isokinetic dynamometer remained unchanged at postoperative 6 months (p = 0.733 and 0.394, respectively). The patients' IKDC score became smaller at postoperative 1 month (p = 0.011) and significantly improved at postoperative 6 months (p = 0.002). CONCLUSION: Using a home-based rehabilitative knee brace system after ACL reconstruction is a viable option as patients maintained their knee muscle strengths maintained their muscle strength and achieve similar or better knee range of motion six months postoperatively.

Physical therapists' experiences and perceptions of antepartum and postpartum care.

BACKGROUND: Little is known about the physical therapists' practice and perceptions toward management of pregnancy/postpartum-related disorders in Taiwan. The aim of this study was to document current practice of physical therapy in antepartum and postpartum care in Taiwan. METHODS: An exploratory, cross-sectional study was conducted in registered physical therapists living in Taiwan. An anonymized online survey was designed, piloted, and advertised widely from March 2020 to March 2021. Data were analyzed using descriptive statistics, Chi square analysis and multivariate logistic regression. RESULTS: Of the 364 respondents, 37.6% had experience of treating pregnant or postpartum women in clinical practice. The most commonly treated pregnancy/postpartum-related disorder in practice was low back pain (61.3%). All respondents reported little to moderate level of confidence in their ability to manage pregnancy/postpartum-related disorder. Being female (p < 0.01); working at a regional hospital (p = 0.01), district hospital or district teaching hospital (p < 0.01), clinic (p = 0.01) or physiotherapy clinic (p = 0.01); and having prior experience of treating antepartum or postpartum women (p < 0.01) were significantly associated with willingness to provide customer-oriented service or health education to patients/clients with pregnancy/postpartum-related disorder after controlling for other confounding variables. The most commonly reported barrier was "lack of available training" (81.3%). CONCLUSION: The majority of participating physical therapists indicated a positive attitude to antepartum and postpartum care but were not confident in management of various pregnancy/postpartum-related disorder in practices. The findings of this study highlight the educational needs related to antepartum and postpartum care in clinical practice for physical therapists in Taiwan.

Reducing the time needed to administer a sustained attention test in patients with stroke.

Administering a sustained attention test often takes a lengthy time, which can hamper routine assessments in clinical settings. Therefore, we first proposed a method to reduce the time needed for administering a sustained attention test (the Computerized Digit Vigilance Test, C-DVT). The method was to retrieve 5 segments from different trial positions of the original C-DVT testing. Then we compared the concurrent validity, convergent validity, and random measurement error of the examinees' performance on these segments to find the segment with better psychometric properties. The 5 segments were as follows: the first 50% of testing, the 21st~50th percentile of testing, the first 60% of testing, the 31st~60th percentile of testing, and the 36th~65th percentile of testing. Then we compared the validities and random measurement error of the examinees' performance on these segments. Ninety patients with stroke participated in the validity study, and 44 of them participated in the random measurement error study. The patients' scores on the 5 segments were highly correlated with those of the C-DVT (Pearson's r ≥ 0.98), indicating excellent concurrent validity. The patients' scores on the 5 segments were moderately correlated with those of the Tablet-based Symbol Digit Modalities Test (Pearson's r = -0.51~-0.48), indicating sufficient convergent validity. The amounts of random measurement error (percent standard error of measurement) were all limited: 5.1% for the C-DVT, 6.6% for the first 50% of testing, 6.0% for the 21st~50th percentile of testing, 6.1% for the first 60% of testing, 6.0% for the 31st~60th percentile of testing, and 6.1% for the 36th~65th percentile of testing. The patients needed on average 3~4 minutes to complete all the aforementioned testing. The patients' scores on the 5 segments showed excellent concurrent validity, sufficient convergent validity, and limited amounts of random measurement error in patients with stroke. We suggest the 31st~60th percentile of testing segment for users because it had the lowest amount of random measurement error and can reduce the time needed for formal testing by about 40%.

Convergent validity and responsiveness of the EQ-5D utility weights for stroke survivors.

OBJECTIVE: This prospective study examined the convergent validity and responsiveness of the EuroQoL-5 Dimensions Health Questionnaire (EQ-5D) utility weights in stroke survivors at the subacute stage. METHODS: Repeated assessments were conducted in rehabilitation wards of a medical centre. A study cohort was recruited from inpatients (n = 478). A total of 342 participants (71.5%) completed 2 assessments; 1 at ward admission and 1 before hospital discharge. Outcome measures, including the Barthel Index (BI), Patient Health Questionnaire (PHQ-9) and EQ-5D, were administered at ward admission and before hospital discharge. RESULTS: The validity of the EQ-5D utility weights was assessed by comparison with the scores of the BI and PHQ-9. The absolute values of Pearson correlation coefficients ranged from 0.40 to 0.52 for the association of EQ-5D utility weights with BI scores and PHQ-9 scores at admission and before hospital discharge. The EQ-5D utility weights had a moderate effect size (0.76), moderate standardized response mean (0.74), and a significant difference (paired t-value = 13.7, p < 0.001) between baseline and follow-up in their ability to detect changes in the health status of stroke survivors staying in a rehabilitation ward. CONCLUSION: This study supports the use of the EQ-5D utility weights as a valid and responsive instrument for performing cost-utility analyses of stroke survivors, including those with higher levels of dependence, at the subacute stage.

An investigation of the factors affecting flatfoot in children with delayed motor development.

This study investigated the prevalence of flatfoot in children with delayed motor development and the relevant factors affecting it. In total, 121 preschool-aged children aged 3-6 with delayed motor development (male: 81; female: 40) were enrolled in the motor-developmentally delayed children group, and 4 times that number, a total of 484 children (male: 324; female: 160), of gender- and age-matched normal developmental children were used as a control group for further analyses. The age was from 3.0 to 6.9 years old for the participants. The judgment criterion of flatfoot was the Chippaux-Smirak index >62.70%, in footprint measurement. The results showed that the prevalence of flatfoot in children with motor developmental delay was higher than that in normal developmental children, approximately 58.7%, and that it decreased with age from 62.8% of 3-year-olds to 50.0% of 6-year-olds. The results also showed that motor-developmentally delayed children with flatfoot are at about 1.5 times the risk of normal developmental children (odds ratio=1.511, p=0.005). In addition, the prevalence of flatfoot is relatively higher in overweight children with delayed motor development, and that in obese children is even as high as 95.8% (23/24). Children with both excessive joint laxity and delayed development are more likely to suffer from flatfoot. The findings of this study can serve as a reference for clinical workers to deal with foot issues in children with delayed motor development.

Characterization of information-based learning benefits with submovement dynamics and muscular rhythmicity.

For skill advancement, motor variability must be optimized based on target information during practice sessions. This study investigated structural changes in kinematic variability by characterizing submovement dynamics and muscular oscillations after practice with visuomotor tracking under different target conditions. Thirty-six participants were randomly assigned to one of three groups (simple, complex, and random). Each group practiced tracking visual targets with trajectories of varying complexity. The velocity trajectory of tracking was decomposed into 1) a primary contraction spectrally identical to the target rate and 2) an intermittent submovement profile. The learning benefits and submovement dynamics were conditional upon experimental manipulation of the target information. Only the simple and complex groups improved their skills with practice. The size of the submovements was most greatly reduced by practice with the least target information (simple > complex > random). Submovement complexity changed in parallel with learning benefits, with the most remarkable increase in practice under a moderate amount of target information (complex > simple > random). In the simple and complex protocols, skill improvements were associated with a significant decline in alpha (8-12 Hz) muscular oscillation but a potentiation of gamma (35-50 Hz) muscular oscillation. However, the random group showed no significant change in tracking skill or submovement dynamics, except that alpha muscular oscillation was reduced. In conclusion, submovement and gamma muscular oscillation are biological markers of learning benefits. Effective learning with an appropriate amount of target information reduces the size of submovements. In accordance with the challenge point hypothesis, changes in submovement complexity in response to target information had an inverted-U function, pertaining to an abundant trajectory-tuning strategy with target exactness.

Change in flatfoot of preschool-aged children: a 1-year follow-up study.

UNLABELLED: The main purpose of this study is to investigate the changes in the signs of flatfoot of preschool-aged children in a 1-year follow-up study. This study performed follow-up on a total of 580 preschool-aged children (boys, 297 children; girls, 283 children) with a median age of 54 (range 36-71 months), and the average follow-up period was 11.8 months. This study used the Chippaux-Smirak index (CSI) of footprint as the assessment tool, and CSI > 62.70 % was used as the standard for determining whether preschool-aged children suffered from flatfoot. The results showed that the signs of flatfoot of preschool-aged children improved with increasing age. At the 1-year follow-up, the average CSI was 5.1 % lower, and the proportion of children with flatfoot was 14 % lower. The follow-up on the change in the signs of flatfoot showed that 37.6 % of the children originally with flatfoot had improved to normal, verifying that flatfoot indeed improves with increasing age. However, the results also showed that 9.9 % of the children who originally had normal feet had developed flatfoot with increasing age, which deserves subsequent investigation. The results of the follow-up also showed that children who were relatively younger, male, obese, and experiencing excessive joint laxity were more likely to experience the signs of flatfoot. CONCLUSION: The 1-year follow-up found that some preschool-aged children with flatfoot may develop normal feet, while children with normal feet may begin to experience the signs. Relevant factors affecting flatfoot in preschool-aged children continue to require further clarification.

Organization of physiological tremors and coordination solutions to postural pointing on an uneven stance surface.

The study investigated the destabilization effect on multi-segment physiological tremors and coordinative control for a postural-suprapostural task under different stance conditions. Twenty volunteers executed postural pointing from a level surface and a seesaw balance board; meanwhile, physiological tremors of the whole postural system and fluctuation movements of fingertip/stance surface were recorded. In reference to level stance, seesaw stance led to much fewer tremor increments of the upper limb and less fluctuation movement of the fingertip than tremor increment of the lower limb and rolling movement of the stance surface. Tremor coupling between the adjacent segments organized differentially with stance surface. In reference to level stance, seesaw stance reinforced tremor coupling of the upper limb but enfeebled the coupling in the arm-lumbar and calf-foot complexes. Stance-related differences in physiological tremors could be explained by characteristic changes in the primary and secondary principal components (PC1 and PC2), with relatively high communality with segment tremors of the lower and upper limbs, respectively. Seesaw stance introduced a prominent 4-8Hz spectral peak in PC1 and potentiated 1-4Hz and 8-12Hz spectral peaks of PC2. Structural reorganization of physiological tremors with stance configuration suggests that seesaw stance involves distinct suprapostural and postural synergies for regulating degree of freedom in joint space.

Comparison of posture and muscle control pattern between male and female computer users with musculoskeletal symptoms.

The primary purpose of this study was to compare the posture and muscle control patterns between male and female computer users with musculoskeletal symptoms. Forty computer users were recruited. Each subject performed a preferred speed typing, a fast speed typing, and a repetitive mouse task. The independent variables were gender, typing speed, and time. There were significant differences between genders for head and neck flexion angles when they were performing the preferred speed typing task. Significant differences between genders were also found for upper extremity angles when they were performing the repetitive mouse task. Male computer users had a smaller root mean square of the right extensor digitorium than females. In general, postural differences were significant between genders, even when the subjects' table and chair were adjusted to meet their anthropometry. Our results suggest that modifications of the computer working environment may be different between genders.

Global effect on multi-segment physiological tremors due to localized fatiguing contraction.

Physiological tremors within a limb are coupled, whereas between-limb tremors are thought to oscillate independently for a healthy subject. This study was undertaken to reinvestigate bilateral tremor relations and intra-limb tremor dynamics for a two-limb task after exhausting a single joint. Fifteen volunteers conducted prolonged tracking with the left (target) shoulder. Neuromuscular functions were monitored before and after the exercise-fatiguing intervention, including tracking displacement, muscle activity of the deltoid, and physiological tremors in the bilateral upper limbs. Localized fatiguing contraction degraded tracking accuracy and movement smoothness, accompanied by an increase in deltoid activation. Segment tremors in the bilateral limbs and inter-limb tremor coherences in 8-12 Hz increased, though coherence peaks in 5-8 Hz waned with fatigue response. Intra-limb tremor relations in the target and non-target limbs were also reorganized with unilateral fatiguing contraction. Tremor coupling in the arm-C7 complexes was enhanced, associated with tremor uncoupling in the forearm-arm and hand-forearm complexes. Tracking error in the pre- fatigue and post-fatigue conditions was predicted by different principal components that had high communalities with tremors of distal and proximal segments of the target limb, respectively. The adaptive changes in tremor dynamics were attributable to fatigue-induced enhancement of common central drive and decline in neural inputs of long-looped reflexes that diverge to contralateral segments.

Relevant factors influencing flatfoot in preschool-aged children.

The aim of this study was to discuss the influence of age, gender, obesity status, joint laxity, and the W-sitting habit on flatfoot in preschool-aged children. A total of 1,598 children (833 boys and 765 girls) between 3 and 6 years of age from kindergartens in the central area of Taiwan were studied. The children were divided into a normal group (n = 733), a unilateral flatfoot group (n = 266), and a bilateral flatfoot group (n = 599), and a multinomial logistic regression model was used to analyze the data. The prevalence of flatfoot decreased significantly with increasing age: 54.5% of 3-year-old but only 21% for 6-year-old children had bilateral flatfoot. In the bilateral flatfoot group, the risk decreased with increased age, increased with increasing weight beyond the normal range, and was higher for boys than girls. Age and obesity status were not significantly influential in the unilateral flatfoot group. Children with higher joint laxity and a habit of W-sitting also experienced higher risk in both flatfoot groups. In conclusion, this study demonstrates a significant association of age, gender, obesity status, joint laxity, and the W-sitting habit with the bilateral flatfoot in preschool-aged children. Children with unilateral flatfoot differ from those with normal feet and bilateral flatfoot. It is suggested that the unilateral flatfoot deserves special attention in future studies.

Directional effect on post-stroke motor overflow characteristics.

Motor overflow (MO) is an involuntary muscle activation associated with strenuous contralateral movement and may become manifested after stroke. The study was undertaken to investigate physiological correlation underlying atypical directional effect of joint movement on post-stroke MO in the affected upper limb. Thirty patients with unilateral post-stroke hemiparesis and fifteen age-matched healthy controls participated in this study. According to motor function assessed with the Fugl-Meyer arm scale, the patients were categorized into two groups of equal number with better (CVA_G; n = 15) or poorer motor functions (CVA_P; n = 15). Surface electromyography (EMG) was used to record irradiated muscle activation from eight muscles of the affected upper limb when the subjects performed maximal isometric contractions in different directions with the unaffected shoulder, elbow and wrist joints. The results showed that only MO amplitude of the CVA_G and the control groups was more sensitive to variations in direction of joint movement in the unaffected arm than the CVA_P group. The CVA_G group exhibited larger amplitudes of MO than the control analog, whereas this tendency was reversed for the CVA_P group. In terms of EMG polar plots, spatial representations of post-stroke MO were insensitive to direction of contralateral movement. The spatial representations of the CVA_G and CVA_P groups were predominated by potent flexion-abduction synergy, contrary to the typical extension adduction synergy seen in the control analog. In conclusion, post-stroke MO amplitude was subject to contralateral movement direction for healthy controls and stroke patients with better motor recovery. However, alterations in MO spatial pattern due to directional effect were not strictly related to the degree of motor deficits of the stroke victims.

The role of kinematic redundancy in adaptation of reaching.

Although important differences exist between learning a new motor skill and adapting a well-learned skill to new environmental constraints, studies of force field adaptation have been used frequently in recent years to identify processes underlying learning. Most of these studies have been of reaching tasks that were each hand position was specified by a unique combination of joint angles. At the same time, evidence has been provided from a variety of tasks that the central nervous system takes advantage of the redundancy available to it when planning and executing functional movements. The current study attempted to determine whether a change in the use of joint motion redundancy is associated with the adaptation process. Both experimental and control subjects performed 160 trials of reaching in each of four adaptation phases, while holding the handle of a robot manipulandum. During the first and last adaptation phases, the robot motors were turned off. During phases 2 and 3 the motors produced a velocity-dependent force field to which experimental subjects had to adapt to regain relatively straight line hand movements during reaching to a target, while the motors remained off for the control group. The uncontrolled manifold (UCM) method was used to partition the variance of planar clavicle-scapular, shoulder, elbow and wrist joint movements into two orthogonal components, one (V(UCM)) that reflected combinations of joint angles that were equivalent with respect to achieving the average hand path and another (V(ORT)) that took the hand away from its average path. There was no change in either variance component for the control group performing 640 non-perturbed reaches across four 'pseudo-adaptation' phases. The experimental group showed adaptation to reaching in the force field that was accompanied initially by an increase in both components of variance, followed by a smaller decrease of V(UCM) than V(ORT) during 320 practice reaches in the force field. After initial re-adaptation to reaching to the null field, V(UCM) was higher in experimental than in control subjects after performing a comparable number of reaches. V(UCM) was also larger in the experimental group after re-adaptation when compared to the 160 null field reaching trials performed prior to initial force field introduction. The results suggest that the central nervous system makes use of kinematic redundancy, or flexibility of motor patterns, to adapt reaching performance to unusual force fields, a fact that has implications for the hypothesis that motor adaptation requires learning of formal models of limb and environmental dynamics.

Electromyographic analyses of global synkinesis in the paretic upper limb after stroke.

BACKGROUND AND PURPOSE: Global synkinesis (GS), or motor irradiation, is an involuntary movement associated with the coactivation of numerous muscles in one limb when the opposite limb is active. The electromyographic (EMG) patterns of people with stroke and people who were healthy were analyzed to characterize GS development in relation to joint involvement and to attempt to relate these findings to clinical observations. SUBJECTS AND METHODS: Twenty patients with stroke, divided into 2 groups with either greater levels of irradiation (SG, n = 10) or lesser levels of irradiation (SL, n = 10), and 20 subjects in a control group were studied. A dynamometer was used to provide resistance for voluntary isometric muscle contractions of the flexor muscle groups of the shoulder, elbow, and wrist. The summated and standardized net EMG amplitudes of 8 principal muscles of the unexercised (paretic) upper extremity were used to characterize intensity and spatial representation of GS. Clinical measurements included the Fugl-Meyer Assessment Scale (FMA), Barthel Index of Activities of Daily Living (BI), and the stage on the Brunnström Stages of Motor Recovery Scale (BR). RESULTS: In the SG and control groups, a more substantial GS intensity was associated with muscle contractions of the flexor muscles of the opposite proximal joint than was the case for contractions of the flexor muscles of the distal joint, whereas such a gradient change was absent in the SL group. The corresponding spatial patterns of GS exhibited a predominant cross-excitation over the unexercised pectoralis major and extensor carpi radialis muscles in the control group, contrary to the enhanced activation of the brachioradialis and biceps brachii muscles noted in patients with stroke. The SG group had a better FMA score and a more satisfactory BR stage than did the SL group, and the 2 neurological scores were related to GS intensity for patients with stroke, depending on joint involvement. DISCUSSION AND CONCLUSION: Intensity of GS provided an affiliation with motor deficits and a promising window for poststroke recovery mechanisms.

Joint coordination during quiet stance: effects of vision.

Stabilization of the center of mass (CM) is an important goal of the postural control system. Coordination of several joints along the human "pendulum" is required to achieve this goal. We studied the coordination among body segments with respect to horizontal CM stabilization during a quiet stance task and the effects of vision on CM stability. Subjects were asked to stand quietly on a narrow wooden block supporting only the mid-foot, with either open (EO) or closed (EC) eyes on separate trials. Instant equilibrium points (IEPs) in the center of pressure (CP) trajectory were determined when the horizontal component of the ground reaction force was zero and the CP data were decomposed into their rambling and trembling components. The joint angle, CM and CP data were divided into short cycles (time-normalized to 100 data points) or longer segments (time-normalized to 1000 data points) of equal length beginning and ending in an IEP. Motor abundance with respect to patterns of joint coordination was evaluated using the uncontrolled manifold (UCM) approach. Here, a UCM is a subspace spanning all joint combinations resulting in a given CM position. All combinations of joint angles that lie within this subspace are equivalent with respect to that CM position while joint angle combinations lying in a subspace orthogonal to the UCM lead to deviation from that CM position. UCM analysis was performed on data organized either across time within longer segments or at each point in time across multiple segments or across multiple cycles. Regardless of method of analysis, most of the variance in joint space was constrained to be within the UCM, preserving the mean CM position in both the EO and EC conditions. Joint configuration variance was significantly higher in the EC than in the EO condition although this increase occurred primarily within the UCM rather than in the orthogonal subspace that would have led to variation of the CM position. These results demonstrate the ability of the control system to selectively "channel" motor variability into directions in joint space that stabilize the CM position. This effect was enhanced when the task was made more challenging in the absence of vision. There was also a significant relationship between joint variance that led to a change in the CM position and, in particular, the rambling component of the CP path, lending some support to the idea that the CNS prescribes a certain stable trajectory of the CP during quiet stance that leads to a small controlled movement of the CM.