Weight-bearing Symmetry Research Articles

Effect of insole on postural control and gait of stroke patients: a systematic review and meta-analysis.

This systematic review aims to examine the evidence of adding postural insole to traditional physical therapy to improve weight distribution, gait, mobility, balance, and postural control in stroke survivors. Five databases were searched to retrieve all related randomized controlled trials examining the effect of insole on stroke patients. Two independent authors checked the potential articles against eligibility criteria according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A meta-analysis was conducted for available outcomes and the statistical heterogeneity was examined using the I2 test. Of 762 articles, only 15 with 448 patients were included after they met the inclusion criteria with most of them including participants exceeding 6 months of stroke incidence. When insole was used as compelled body weight shifting method, pooled statistical analysis revealed significant improvement in gait velocity [standardized mean difference (SMD) = 0.67; 95% confidence interval (CI): 0.31, 1.02; P = 0.0003], cadence (SMD = 0.67; 95% CI: 0.16, 1.18; P = 0.01] and stride length (SMD = 1.11; 95% CI: 0.57, 1.65; P < 0.0001), while no significant effect on step length (SMD = 0.48; 95% CI: -0.37, 1.33; P = 0.27). Pooled statistical analysis of balance outcomes revealed significant improvement in weight-bearing symmetry balance (SMD = 0.82; 95% CI: 0.25, 1.39; P = 0.005) and long-term improvement in Berg Balance Scale (SMD = 1.19; 95% CI: 0.19, 2.20; P = 0.02), while no difference was observed in balance confidence (SMD = 0.44; 95% CI: -0.15, 1.04; P = 0.14) and sensorimotor functions (SMD = 0.36; 95% CI -0.39, 1.11; P = 0.35). Insoles significantly improved spatiotemporal gait parameters, gait symmetry, and static balance compared with traditional physical therapy alone.

The efficacy of vitamin E in preventing arthrofibrosis after joint replacement.

Arthrofibrosis is a joint disorder characterized by excessive scar formation in the joint tissues. Vitamin E is an antioxidant with potential anti-fibroblastic effect. The aim of this study was to establish an arthrofibrosis rat model after joint replacement and assess the effects of vitamin E supplementation on joint fibrosis. We simulated knee replacement in 16 male Sprague-Dawley rats. We immobilized the surgical leg with a suture in full flexion. The control groups were killed at 2 and 12 weeks (n = 5 per group), and the test group was supplemented daily with vitamin E (0.2 mg/mL) in their drinking water for 12 weeks (n = 6). We performed histological staining to investigate the presence and severity of arthrofibrosis. Immunofluorescent staining and α2-macroglobulin (α2M) enzyme-linked immunosorbent assay (ELISA) were used to assess local and systemic inflammation. Static weight bearing (total internal reflection) and range of motion (ROM) were collected for functional assessment. The ROM and weight-bearing symmetry decreased after the procedure and recovered slowly with still significant deficit at the end of the study for both groups. Histological analysis confirmed fibrosis in both lateral and posterior periarticular tissue. Vitamin E supplementation showed a moderate anti-inflammatory effect on the local and systemic levels. The vitamin E group exhibited significant improvement in ROM and weight-bearing symmetry at day 84 compared to the control group. This model is viable for simulating arthrofibrosis after joint replacement. Vitamin E may benefit postsurgical arthrofibrosis, and further studies are needed for dosing requirements.

Sort-term adaptations on bilateral body weight-bearing symmetry and postural control through the application of rotary prisms in healthy children

Background: Motor-control is organized by coordinated sensory systems which integrate for the preparation of movement. Certain visuoperceptive disorders may impair proper development of motor control during childhood, thereby impacting functional aspects like bilateral weight-bearing symmetry. Rotary prisms (RPs) are a rehabilitation modality that have shown promise in facilitating motor-control and spatial-realignment for adults, improving weight-bearing symmetry, often evaluated by indexes like the normalized symmetry index (NSI%). However, less is known for the short-term effect of RPs on NSI% and consequent effects on functional capacity in healthy children. Methods: We evaluated the acute and short-term chronic effect of RPs in fourteen healthy children (8.8±1.1 years) on NSI% and the total execution time (s) of a dynamic balance sit-to-stand task (SITS). Measurements were performed at baseline, immediately following RP application (immediate phase) and 10 min following RP removal (spatial re-alignment). Results: We detected an overall main effect of time on NSI% (F=15.1, p&lt;0.001, η2=.54), improving both immediate (-67.3%, 3.4±4.46%, p&lt;0.001) and spatial re-alignment phases (-55.3%, 5.2±4.3%, p&lt;0.001) compared to baseline (9.7±1.9 %). Moreover, no significant differences for NSI% between immediate and spatial re-alignment phases were detected (p&gt;0.05). However, TUT of the SITS task remained unaffected (F=1.13, p&gt;0.05). Conclusions: Non-significant differences for NSI% between immediate and spatial re-alignment phases indicate that short-term neural adaptations may persist following the removal of RPs in healthy children. Indicating the potential suitability of RPs in neurorehabilitation for children with balance impairments, such as pre-existing sensory motor dysfunctions and others.

Postural Control and Weight Bearing Symmetry Patterns in Patients Post Lumbar Spinal Decompression Surgery

Background Prolapsed intervertebral disc is one of the most common reasons for low back pain often causing altered postural control and weight bearing symmetry of foot. Although these components are known to be affected there is limited literature available explaining the postural control and weight bearing symmetry post spinal decompression surgical procedures.Objective The study was formulated with the objective to understand postural control and symmetry of weight bearing patterns among patients post lumbar spinal decompression surgery.Methods The study was conducted involving 65 patients who were assessed pre-and post-lumbar decompression surgery. Nintendo Wii balance board was used to assess the patients at all intervals.Results The post-surgical values at discharge showed a clinical improvement in postural control bilaterally left P0.068 and right P0.031 but showed deterioration at one month with right P0.076 and significant on left side P0.009. Contrary to this the follow up values at one month showed a significant improvement in weight bearing symmetry P0.001. Pain values both on activity and at rest taken at both follow-up intervals F1 and F2 showed a statistically significant reduction P0.001.Conclusion Postural control assessed with single limb stance shows worsening at one month post decompression procedure. Weight bearing symmetry parameters may demonstrate a decline immediately post lumbar decompression surgery but may show a significant improvement along with reduction in pain post surgically as early as one month.

A powered prosthesis supports weight-bearing stand-to-sit transitions.

Above-knee amputees were capable of weight-bearing symmetry during stand-to-sit transitions when using a powered prosthesis.

Improved weight bearing during gait at 6 weeks post-surgery with an angle stable locking system after distal tibial fracture

BackgroundFunctional recovery after intramedullary nailing of distal tibial fractures can be monitored using ipsilateral vertical ground reaction forces (vGRF), giving insight into recovery of patients’ gait symmetry. Previous work compared patient cohorts to healthy controls, but it remains unclear if these metrics can identify treatment-based differences in return to function post-surgery. Research questionIs treatment of a distal tibial fracture with intramedullary nailing with an angle stable locking system (ASLS) associated with higher ipsilateral vGRF and improved symmetry compared to conventional intramedullary nailing at an early time point? MethodsThirty-nine patients treated with ASLS intramedullary nailing were retrospectively compared to thirty-nine patients with conventional locking. vGRFs were collected at 1, 6, 12, 26, and 52 weeks post-surgery during standing and gait. Discrete metrics of ipsilateral vGRF (maximal force, impulse) and asymmetry were compared between treatments at each time point. Time-scale comparisons of ipsilateral vGRF and lower limb asymmetry were additionally performed for gait trials. Mann-Whitney Test or a two-way analysis of variance tested discrete comparisons; statistical non-parametric mapping tested time-scale data between treatment groups. ResultsDuring gait, ASLS-treated patients applied more load on the operated limb (17–38% stance, p = 0.015) and consequently loaded limbs more symmetrically (8–37% stance, p = 0.008) during the loading response at 6 weeks post-surgery compared to conventional IM treatment. Discrete measures of symmetry at the same time point identified treatment-based differences in maximal force (p = 0.039) and impulse (p = 0.012), with ASLS-treated patients exhibiting more symmetry. No differences were identified in gait trials at later time points nor from all standing trials. SignificanceDuring the initial loading response of gait, increased ipsilateral vGRF and improved weightbearing symmetry were identified in ASLS patients at 6 weeks post-surgery compared to conventional IM nailing. Early and objective metrics of dynamic movement are suggested to identify treatment-based differences in functional recovery.

The effect of brace use on balance in individuals with adolescent idiopathic scoliosis.

Patients with adolescent idiopathic scoliosis (AIS) have poorer standing balance compared with their healthy peers. However, the immediate effects of the braces used in the treatment on balance remain uncertain. To investigate the effect of brace use on balance and weight-bearing symmetry in patients with AIS and to compare the results of different brace designs. Observational. A total of 21 patients with AIS aged 10-17 years using 10 Boston and 11 Cheneau braces participated. Immediate balance and weight-bearing symmetries of patients with and without their own braces were evaluated. Balance assessment was performed using the Sensory Organization Test (SOT) on a computerized dynamic posturography device. Weight-bearing symmetry was evaluated on the computerized dynamic posturography device with the knees in full extension, with the knees flexed at 30°, 60°, and 90°. Regardless of its design, it was found that brace use had no effect on immediate balance and weight-bearing symmetry ( p > 0.05). Of the patients using a Boston brace, unbraced SOT condition 2, 3, and 5 and composite scores were found to be higher than their braced scores ( p < 0.05). Braced SOT condition 3 scores of the patients using a Cheneau brace were higher than those using a Boston brace ( p = 0.037). Brace use and brace types have no statistical effect on weight-bearing symmetry. It was observed that brace use in patients with AIS has no positive effect on immediate balance and weight-bearing symmetry, and the use of Boston brace negatively affects immediate balance scores and increases visual dependence.

Asymmetric shoe height induces reactive changes in gait kinematics but not kinetics in healthy young adults

BackgroundFootwear interventions are a potential avenue to correct walking asymmetry in neurologic populations, such as stroke. However, the motor learning mechanisms that underlie the changes in walking imposed by asymmetric footwear are unclear. Research questionThe objectives of this study were to examine symmetry changes during and after an asymmetric shoe height intervention in (1) vertical impulse and (2) spatiotemporal gait parameters and (3) joint kinematics, in healthy young adults MethodsEleven healthy young adults (3 males, 8 females; 21.2 ± 3.1 years old) participated in this study. Participants walked on an instrumented treadmill at 1.3 m/s for four conditions: (1) a 5-minute familiarization with equal shoe height, (2) a 5-minute baseline with equal shoe height, (3) a 10-minute intervention, where participants walked with asymmetric shoe height with a 10 mm shoe insert in one shoe, and (4) a 10-minute post-intervention, where participants walked with equal shoe height. Asymmetry in kinetics and kinematics were used to identify changes during intervention and aftereffects, a hallmark of feedforward adaptation ResultsParticipants did not alter vertical impulse asymmetry (p = 0.667) nor stance time asymmetry (p = 0.228). During the intervention, step time asymmetry (p = 0.003) and double support asymmetry (p < 0.001) were greater compared to baseline. Leg joint asymmetry during stance (Ankle plantarflexion: p < 0.001; Knee flexion: p < 0.001; Hip extension: p = 0.011) was greater during the intervention compared to baseline. However, changes in spatiotemporal gait variables and joint mechanics did not demonstrate aftereffects. SignificanceOur results show that healthy human adults change gait kinematics, but not weight-bearing symmetry with asymmetrical footwear. This suggests that healthy humans prioritize maintaining vertical impulse by changing their kinematics. Further, the changes in gait kinematics are short-lived, suggesting feedback-based control, and a lack of feedforward motor adaptations

Can a powered knee-ankle prosthesis improve weight-bearing symmetry during stand-to-sit transitions in individuals with above-knee amputations?

BackgroundAfter above-knee amputation, the missing biological knee and ankle are replaced with passive prosthetic devices. Passive prostheses are able to dissipate limited amounts of energy using resistive damper systems during “negative energy” tasks like sit-down. However, passive prosthetic knees are not able to provide high levels of resistance at the end of the sit-down movement when the knee is flexed, and users need the most support. Consequently, users are forced to over-compensate with their upper body, residual hip, and intact leg, and/or sit down with a ballistic and uncontrolled movement. Powered prostheses have the potential to solve this problem. Powered prosthetic joints are controlled by motors, which can produce higher levels of resistance at a larger range of joint positions than passive damper systems. Therefore, powered prostheses have the potential to make sitting down more controlled and less difficult for above-knee amputees, improving their functional mobility.MethodsTen individuals with above-knee amputations sat down using their prescribed passive prosthesis and a research powered knee-ankle prosthesis. Subjects performed three sit-downs with each prosthesis while we recorded joint angles, forces, and muscle activity from the intact quadricep muscle. Our main outcome measures were weight-bearing symmetry and muscle effort of the intact quadricep muscle. We performed paired t-tests on these outcome measures to test for significant differences between passive and powered prostheses.ResultsWe found that the average weight-bearing symmetry improved by 42.1% when subjects sat down with the powered prosthesis compared to their passive prostheses. This difference was significant (p = 0.0012), and every subject’s weight-bearing symmetry improved when using the powered prosthesis. Although the intact quadricep muscle contraction differed in shape, neither the integral nor the peak of the signal was significantly different between conditions (integral p > 0.01, peak p > 0.01).ConclusionsIn this study, we found that a powered knee-ankle prosthesis significantly improved weight-bearing symmetry during sit-down compared to passive prostheses. However, we did not observe a corresponding decrease in intact-limb muscle effort. These results indicate that powered prosthetic devices have the potential to improve balance during sit-down for individuals with above-knee amputation and provide insight for future development of powered prosthetics.

Effect of Increasing Assistance From a Powered Prosthesis on Weight-Bearing Symmetry, Effort, and Speed During Stand-Up in Individuals With Above-Knee Amputation.

After above-knee amputation, the missing biological knee and ankle are commonly replaced with a passive prosthesis, which cannot provide net-positive energy to assist the user. During activities such as sit-to-stand, above-knee amputees must compensate for this lack of power using their upper body, intact limb, and residual limb, resulting in slower, less symmetric, and higher effort movements. Previous studies have shown that powered prostheses can improve symmetry and speed by providing positive assistive power. However, we still lack a systematic investigation of the effect of powered prosthesis assistance. Without this knowledge, researchers and clinicians have no framework for tuning powered prostheses to optimally assist users. Here we show that varying the assistive knee torque significantly affected weight-bearing symmetry, effort, and speed during the stand-up movement in eight above-knee amputees. Specifically, we observed improvements in the index of asymmetry of the vertical ground reaction force at the point approximating maximum vertical center of mass acceleration, the integral of the intact vastus medialis activation measured using electromyography, and the stand-up duration compared to the passive prosthesis. We saw significant improvements in all three metrics when subjects used the powered prosthesis compared to the passive prosthesis. We saw improvements in all three metrics with increasing assistive torque levels commanded by the powered prosthesis. We also observed increased weight-bearing asymmetry at the end of movement, and increased kinematic asymmetry with increasing assistance from the powered prosthesis. These results show that powered prostheses can improve functional mobility, potentially increasing quality of life for millions of people living with above-knee amputations.

Evaluation of Four Clinical Metrology Instruments for the Assessment of Osteoarthritis in Dogs.

Simple SummaryOsteoarthritis is a very common joint disease in dogs. For that reason, it is important to have validated owner questionnaires to assess patients and response to eventual treatments. For dogs, several questionnaires exist, with a growing interest on their validation. We aimed to evaluate four of them and determine their ability to evaluate pain and patient outcome. The questionnaires we evaluated can be used for the evaluation of osteoarthritis and response to treatment in dogs.Osteoarthritis (OA) is the most commonly diagnosed joint disease in companion animals, and proper tools are necessary to assess patients and response to treatment. We aimed to perform the psychometric evaluation of several clinical metrology instruments (CMI), developed to evaluate pain and assess outcome. Fifty police working dogs with bilateral hip OA were assessed in a prospective, randomised, double-blinded study. Patients were evaluated using a stance analyser in six different moments divided over a 180-day period. Pedometer step count, weight-bearing symmetry index and deviation from normal weight-bearing were calculated and used for criterion validity. In each evaluation moment, a copy of the Hudson Visual Analogue Scale (HVAS), Canine Brief Pain Inventory (CBPI), Liverpool Osteoarthritis in Dogs (LOAD) and Canine Orthopaedic Index (COI) were completed by the dogs’ handlers. Correlations between CMIs were evaluated as construct validity. Further evaluation was performed with the Kaiser–Meyer–Olin measure of sampling adequacy, Eigenvalue and scree-plot analysis. Internal consistency was tested with Cronbach’s α. Significant weak correlation was found between all CMIs and stance analysis symmetry index measure and deviation, indicating criterion validity. Significant weak correlation was also found between pedometer count and LOAD plus COI. Cronbach’s α was 0.80 for HVAS, 0.98 for CBPI, 0.97 for LOAD and 0.98 for COI. Significant strong correlation was observed between CMIs, indicating construct validity. We present criterion and construct validity of these CMIs, which are able to capture various dimensions of OA. They can be used for the evaluation of osteoarthritis and response to treatment in dogs.

The Recovery of Weight-Bearing Symmetry After Total Hip Arthroplasty Is Activity-Dependent.

This study aimed to characterize ipsilateral loading and return to weight-bearing symmetry (WBS) in patients undergoing total hip arthroplasty (THA) during activities of daily living (ADLs) using instrumented insoles. A prospective study in 25 THA patients was performed, which included controlled pre- and postoperative follow-ups in a single rehabilitation center of an orthopedic department. Ipsilateral loading and WBS of ADLs were measured with insoles in THA patients and in a healthy control group of 25 participants. Measurements in the THA group were performed at 4 different visits: a week pre-THA, within a week post-THA, 3–6 weeks post-THA, and 6–12 weeks post-THA, whereas the healthy control group was measured once. ADLs included standing comfortably, standing evenly, walking, and sit-to-stand-to-sit (StS) transitions. All ADLs were analyzed using discrete methods, and walking included a time-scale analysis to provide temporal insights in the ipsilateral loading and WBS waveforms. THA patients only improved beyond their pre-surgery levels while standing comfortably (ipsilateral loading and WBS, p < 0.05) and during StS transitions (WBS, p < 0.05). Nevertheless, patients improved upon their ipsilateral loading and WBS deficits observed within a week post-surgery across all investigated ADLs. Ipsilateral loading and WBS of THA patients were comparable to healthy participants at 6–12 weeks post-THA, except for ipsilateral loading during walking (p < 0.05) at the initial and terminal double-leg support period of the stance phase. Taken together, insole measurements allow for the quantification of ipsilateral loading and WBS deficits during ADLs, identifying differences between pre- and postoperative periods, and differentiating THA patients from healthy participants. However, post-THA measurements that lack pre-surgery assessments may not be sensitive to identifying patient-specific improvements in ipsilateral loading and WBS. Moreover, StS transitions and earlier follow-up time points should be considered an important clinical metric of biomechanical recovery after THA.

A Symmetry Evaluation Model for Lower Limb Segments During Upper Limb Loading

Weight-bearing is a common behavior, whereas a load impact on human gait symmetry is seldom considered. This study aims to propose and verify a gait symmetry detection model, by using the gait symmetry under different weight-bearing states to establish a weight-bearing symmetry classification rule, and to measure the consistency of movement through multiple gait symmetry experiments. In details, a classifier combined with statistical learning is presented to quantify the signal difference between left and right legs. The quantization result is incorporated as an index to judge the magnitude of symmetry. Meanwhile, a dynamic time warping (DTW) algorithm is introduced to calculate the signal similarity of two legs in time domain as well as another index. The symmetry trend on leg signals is also considered and described as a third index. By casting these indexes in the proposed detection model, we employ several existing nonlinear classification methods to effectively disclose the difference between legs. Moreover, the information between legs can also be extracted through time warping, yielding the detection model competitive. The validity of the model is verified by hypothetical test. Compared with some state-of-the-art methods, our model achieves an improvement over 5% in the consistency measure of the calf. The symmetry measure of calf and thigh is also test. The proposed method outperforms other methods with the improvement of 12.5%.

Accommodating variable-resistance exercise enhance weight-bearing/gait symmetry and balance capability in children with hemiparetic cerebral palsy: a parallel-group, single-blinded randomized clinical trial.

Children with hemiparetic cerebral palsy (HCP) tend preferentially to bear their body weight on the non-paretic side, which leads to the emergence of asymmetrical walking patterns and limited ability to maintain balance. Therefore, improved and clearly effective intervention strategies to remedy these impairments are needed. This study endeavored to evaluate the efficacy of an accommodating variable-resistance exercise (AVr-Ex) program on weight-bearing symmetry, gait symmetry, and dynamic balance in children with HCP. This study employed a parallel-group, single-blinded randomized controlled design. Physical Therapy Outpatient Clinic and University Hospital, and a tertiary referral hospital. Thirty-six children with HCP aged between eight and 16 years were assigned randomly to the AVr-Ex group (N.=18) or control group (N.=18). Children in the AVr-Ex group undergone an AVr-Ex program, three sessions/week over eight consecutive weeks, besides the usual physical therapy while children in the Control group received the usual physical therapy alone. Outcome measures were evaluated before and after intervention and included weight-bearing symmetry indices [rearfoot (RF-WbSI), and forefoot (FF-WbSI)], gait symmetry indices (spatial [GSI<inf>spatial</inf>], and temporal [GSI<inf>temporal</inf>]), and dynamic balance. The post-treatment RF-WbSI (P<0.001; η<inf>p</inf>2=0.41), GSI<inf>spatial</inf> (P<0.001; η<inf>p</inf>2=0.42), GSI<inf>temporal</inf> (P<0.001; η<inf>p</inf>2=0.52), and dynamic balance variables (all P<0.05; η<inf>p</inf>2 ranged from 0.21 to 0.51) improved significantly in the AVr-Ex group compared to the control group, when controlled for the pre-treatment scores. This study suggests that AVr-Ex can improve weight-bearing symmetry, gait symmetry, and dynamic balance in children with HCP when incorporated into the usual physical rehabilitation program. AVr-Ex is likely an effective training paradigm to address weight-bearing/gait asymmetry and balance issues in children with HCP, which provides the basis for its incorporation in rehabilitation programs for such a patient population.

Postural Control Strategies and Balance-Related Factors in Individuals with Traumatic Transtibial Amputations.

Mechanisms behind compromised balance control in people with transtibial amputation need to be further explored, as currently little is known specifically about postural control strategies in people with traumatic transtibial amputation (tTTA). The aim of this study is to assess automatic and voluntary postural control strategies in individuals with unilateral tTTA compared to those in control subjects and to define the effect of balance-related factors on these strategies. Automatic posture reactions and volitional motion toward given direction using standardized posturographic protocols (NeuroCom) of the Motor Control Test (MCT) and Limits of Stability (LOS) were assessed in eighteen participants with tTTA and eighteen age-matched controls. Compared to the controls, the participants with tTTA bore less weight on the prosthetic leg (p < 0.001) during the MCT and had reduced inclination toward the prosthetic leg (p < 0.001) within the LOS. In the tTTA group, the weight-bearing symmetry and the inclination toward the prosthetic leg (p < 0.05) was positively correlated with prosthesis use duration (p < 0.05). The current study indicates that decreased utilization of the prosthetic leg in tTTAs represents adaptive postural control strategy, but as prosthesis use duration increased, the engagement of the prosthetic leg improved.

Sit-to-Stand Weight-Bearing Symmetry Performance in Total Knee Arthroplasty: Recovery Curves, Correlates, and Predictive Validity With Gait Speed.

After total knee arthroplasty, the ability to weight bear symmetrically during the sit-to-stand task provides important information regarding altered movement patterns. Despite this, comprehensive recovery curves and validity data for sit-to-stand weight-bearing symmetry are lacking in the total knee arthroplasty population. Our study aimed to (1) develop recovery curves with reference ranges, (2) identify the correlates of standard and constrained sit-to-stand weight-bearing symmetry, and (3) evaluate their predictive validity with gait speed. We performed a retrospective longitudinal study of 706 patients with primary unilateral total knee arthroplasty. Monthly, for 4 mos after surgery, sit-to-stand weight-bearing symmetry, knee pain, knee range of motion, quadriceps strength, and gait speed were quantified. Standard and constrained sit-to-stand weight-bearing symmetry measures improved nonlinearly over time. Standard sit-to-stand weight-bearing symmetry was most strongly associated with bilateral quadriceps strength, whereas constrained sit-to-stand weight-bearing symmetry was most strongly associated with ipsilateral quadriceps strength. Knee range of motion and contralateral knee pain were additional correlates. Both standard sit-to-stand and constrained sit-to-stand weight-bearing symmetry were independently and nonlinearly associated with gait speed in multivariable models. Our study provided recovery curves and validity data to support routine clinical measurement of sit-to-stand weight-bearing symmetry in total knee arthroplasty. Our results also indicate that constrained sit-to-stand may promote greater use of the operated limb than standard sit-to-stand.

Core Stability Exercises Yield Multiple Benefits for Patients With Chronic Stroke: A Randomized Controlled Trial.

This study examined the effect of core stability exercises on trunk control, core muscle strength, standing weight-bearing symmetry, and balance confidence of people with chronic stroke. This was an assessor-blinded randomized controlled trial involving 84 ambulatory patients with middle cerebral artery stroke, randomly assigned to three training groups. Two experimental groups practiced core stability exercises either on stable or on unstable support surfaces. In contrast, the control group received standard physiotherapy. All the participants underwent an hour-long training session a day, thrice a week over a 6-wk duration, and followed-up after 12 mos. Trunk Impairment Scale, core muscle strength, weight-bearing asymmetry in standing, and Activities-specific Balance Confidence scale were the outcome measures. Compared with the control group, the two experimental groups demonstrated a significant improvement on all the outcome measures from baseline to posttraining and from baseline to 12-mo follow-up (P < 0.001). The two experimental groups demonstrated no significant difference between them on all the measures (P > 0.05). Core stability exercises on stable and unstable support surfaces are equally beneficial in improving trunk control, core muscle strength, standing weight-bearing symmetry, and balance confidence of ambulatory patients with chronic stroke than the standard physiotherapy.

Trunk kinematics and muscle activation patterns during stand-to-sit movement and the relationship with postural stability in aging

BackgroundStand-to-sit (StandTS) movement is an important functional activity that can be challenging for older adults due to age-related changes in neuromotor control. Although trunk flexion, eccentric contraction of the rectus femoris (RF), and coordination of RF and biceps femoris (BF) muscles are important to the StandTS task, the effects of aging on these and related outcomes are not well studied. Research questionWhat are the age-related differences in trunk flexion, lower extremity muscle activation patterns, and postural stability during a StandTS task and what is the relationship between these variables? MethodsTen younger and ten older healthy adults performed three StandTS trials at self-selected speeds. Outcomes included peak amplitude, peak timing, burst duration, and onset latency of electromyography (EMG) activity of the RF and BF muscles, trunk flexion angle and angular velocity, whole body center of mass (CoM) displacement, center of pressure (CoP) velocity, and ground reaction force (GRF). ResultsThere were no age-related differences in weight-bearing symmetry, StandTS and trunk flexion angular velocity, or BF activity. In both groups, EMG peak timing of RF was preceded by BF. Compared to younger adults, older adults demonstrated shorter RF EMG burst duration, reduced trunk flexion, and reduced stability as indicated by the longer duration in which CoM was maintained beyond the posterior limit of base of support (BoS), greater mean anterior-posterior CoP velocity and larger standard deviation of CoM vertical acceleration during StandTS with smaller vertical GRF immediately prior to StandTS termination. Trunk flexion angle and RF EMG burst duration correlated with stability as measured by the duration in which the CoM stayed within the BoS. SignificanceDecreased trunk flexion and impaired eccentric control of the RF are associated with StandTS instability in aging and suggest the importance of including StandTS training as a part of a comprehensive balance intervention.

Characterizing inter-limb synchronization after incomplete spinal cord injury: A cross-sectional study

BackgroundIndividuals with incomplete spinal cord injury (iSCI) demonstrate greater postural sway and increased dependency on vision to maintain balance compared to able-bodied individuals. Research on standing balance after iSCI has focused on the joint contribution of the lower limbs; however, inter-limb synchrony in quiet standing is a sensitive measure of individual limb contributions to standing balance control in other neurological populations. It is unknown if and how reduced inter-limb synchrony contributes to the poor standing balance of individuals with iSCI. Research questionHow does an iSCI affect inter-limb synchrony and weight-bearing symmetry in standing? MethodsEighteen individuals with non-progressive motor iSCI and 15 age- and sex-matched able-bodied individuals (M-AB) were included in the study. Participants stood in a standardized position on two adjacent force plates in eyes open and closed conditions for 70 s per condition. Net centre-of-pressure (COP) root mean square (RMS), net COP velocity, COP inter-limb synchrony (i.e. cross-correlation between left and right COP), and weight-bearing asymmetry (i.e. vertical force from each limb over total vertical force) were calculated. Muscle strength of the lower limbs was assessed with manual muscle testing. ResultsIndividuals with iSCI demonstrated reduced inter-limb synchrony when standing with eyes open and eyes closed, but did not differ to M-AB with respect to weight-bearing asymmetry. They also produced greater net COP RMS and velocity when compared to M-AB. Muscle strength of the two lower limbs demonstrated an overall asymmetry in individuals with iSCI. SignificanceIndividuals with iSCI demonstrated impaired balance control as evidenced by reduced inter-limb synchrony and greater COP RMS and velocity compared to M-AB individuals. This increased understanding of how balance control is impaired following iSCI may inform balance assessment and intervention for this population. Future work examining the association between inter-limb synchrony and the occurrence of falls in iSCI is warranted.

Effects of Compelled Body Weight Shift Therapy on Weight-Bearing Symmetry, Balance and Gait in Patients with Stroke: A Narrative Review

Effects of Compelled Body Weight Shift Therapy on Weight-Bearing Symmetry, Balance and Gait in Patients with Stroke: A Narrative Review