Swing Time Asymmetry Research Articles

Effects of Sport Participation on Gait Coordination, Symmetry, and Variability in Older Adults.

The aim of this study was to compare the interlimb coordination, asymmetry, and variability between older adults who participated in sports (n = 25; age = 72.6 ± 6.46years) and sedentary older adults (n = 20; age = 70.85 ± 3.82years). The sport participants were selected from tennis and badminton clubs, whereas the sedentary participants were recruited from local community centers. The participants walked at their preferred speed in a 10-m walkway for 2min. The interlimb coordination was measured by the phase coordination index. Other walking metrics were speed, cadence, swing time, stance time, double-support time, stride time, and swing time asymmetry. The results showed that the sport participants relative to the sedentary group had better interlimb coordination, higher walking speed and cadence, and less swing time variability. Young older adults also had a better interlimb coordination. In conclusion, the findings of this study showed that long-term participation in sports has some antiaging benefits on gait coordination and symmetry in older adults.

Exploring Temporospatial Gait Asymmetry, Dynamic Balance, and Locomotor Capacity After a 12-Week Split-Belt Treadmill Training in Adolescents with Unilateral Cerebral Palsy: A Randomized Clinical Study

Aim To investigate the effects of a 12-week split-belt treadmill walking (Sb-TW) practice using an error augmentation strategy on temporospatial gait asymmetries, dynamic balance, and locomotor capacity in adolescents with unilateral cerebral palsy (ULCP). Methods Fifty-two adolescents with ULCP (age: 10–16 years) were randomized into either the Sb-TW group (n = 26; underwent repeated Sb-TW practice, with exaggeration of the initial step-length asymmetry, three times/week, for 12 sequential weeks) or control group (n = 26; received equivalent dosages of traditional single-belt treadmill training). Step-length and swing-time asymmetries, directional (LoSdirectional) and overall (LoSoverall) limits of stability, and locomotor capacity [6-minute walk test (6-MWT), Timed Up and Down Stair test (TUDS), and 10-m Shuttle Run Test (10mSRT)] were assessed pre- and post-intervention. Results The Sb-TW group demonstrated more favorable changes in step-length asymmetry (p < .001, η 2 partial = 0.27), LoSdirectional [affected side direction (p = .033, η 2 partial = 0.09), forward direction (p = .004, η 2 partial = 0.16), and backward direction (p = .01, η 2 partial = 0.12)], and LoSoverall (p < .001, η 2 partial = 0.31) than the control group. Also, the Sb-TW group showed significantly higher locomotor capacity [6-MWT (p < .001, η 2 partial = 0.38), TUDS (p = .032, η 2 partial = 0.09), 10mSRT (p = .021, η 2 partial = 0.10)] as compared to the control group. Conclusion The Sb-TW-induced adaptations can be capitalized on for remediating spatial gait asymmetry, dynamic balance deficits, and impaired locomotor performance in adolescents with ULCP.

Effect of Aquatic Treadmill Training on Patients with Hemiplegia after Stroke

<bold>Objective</bold> To observe the effect of aquatic treadmill training on resting muscle thickness of the affected side and walking functions of patients with hemiplegia after stroke. <bold>Methods</bold> A total of 40 patients with hemiplegia after stroke hospitalized in the China Rehabilitation Research Center from March 2021 to October 2021, were divided randomly into control group and experiment group according to the random series generated by SPSS 26.0 software, with 20 patients in each group. Both groups received conventional rehabilitation treatment (basic movement training, motor function facilitation, dynamic standing balance training, walking training, etc.), 30 minutes a time, once a day, five days a week, lasting for four weeks. In addition to the conventional rehabilitation treatment, the control group received gait training with the overhead track system and the experiment group received aquatic treadmill training. Both groups were treated for 20 minutes a day, five days a week, lasting for four weeks. Before and after treatment, a full digital handheld color ultrasound diagnostic instrument was used to measure the muscle thickness of obliquus externus abdominis (EO）, internal abdominal oblique (IO), transverse abdominal (TrA), rectus femoris (RF), tibialis anterior (TA) and medial gastrocnemius (MG). GaitWatch 3D gait analysis and sports training system was used to measure velocity, swing time asymmetry ratio and step length asymmetry ratio. <bold>Results</bold> 1) Muscle thickness: compared with that before treatment, the thickness of RF and TA muscles in the control group increased significantly after treatment; the thickness of EO, IO, TrA, RF and TA muscles of the experiment group increased significantly after treatment, the difference was statistically significant (<italic>P</italic>&lt;0.05). Compared with the control group, there was significant increases in thickness of EO, IO, RF and TA muscles in the experiment group (<italic>P</italic>&lt;0.05). 2) Gait velocity, swing time asymmetry ratio, step length asymmetry ratio: compared with that before treatment, gait velocity of both groups after treatment increased significantly, and step length asymmetry ratio decreased significantly, the difference was statistically significant (<italic>P</italic>&lt;0.05). <bold>Conclusion</bold> The aquatic treadmill training can improve the affected side muscle thickness, gait velocity and step length asymmetry ratio of patients with hemiplegia after stroke, and is recommended for clinical application.

Efficacy of electromechanical-assisted gait training on clinical walking function and gait symmetry after brain injury of stroke: a randomized controlled trial

Electromechanical-assisted gait training may be an effective intervention to promote motor recovery after brain injury. However, many studies still have difficulties in clarifying the difference between electromechanical-assisted gait training and conventional gait training. To evaluate the effectiveness of electromechanical-assisted gait training compared to that of conventional gait training on clinical walking function and gait symmetry of stroke patients. We randomly assigned patients with stroke (n = 144) to a control group (physical therapist-assisted gait training) and an experimental group (electromechanical gait training). Both types of gait training were done for 30 min each day, 5 days a week for 4 weeks. The primary endpoint was the change in functional ambulatory category (FAC). Secondary endpoints were clinical walking functions and gait symmetries of swing time and step length. All outcomes were measured at baseline (pre-intervention) and at 4 weeks after the baseline (post-intervention). FAC showed significant improvement after the intervention, as did clinical walking functions, in both groups. The step-length asymmetry improved in the control group, but that in the experimental group and the swing-time asymmetry in both groups did not show significant improvement. In the subgroup analysis of stroke duration of 90 days, FAC and clinical walking functions showed more significant improvement in the subacute group than in the chronic group. However, gait symmetries did not show any significant changes in either the subacute or the chronic group. Electromechanically assisted gait training by EXOWALK was as effective as conventional gait training with a physiotherapist. Although clinical walking function in the subacute group improved more than in the chronic group, gait asymmetry did not improve for either group after gait training.Trial registration: KCT0003411 Clinical Research Information Service (CRIS), Republic of Korea.

Components of gait in people with and without mild cognitive impairment

BackgroundSeveral objective gait parameters are associated with cognitive impairment, but there is limited knowledge of gait models in people with mild cognitive impairment (MCI). Research questionHow can 18 objective gait characteristics be used to define different components of gait in people with MCI (with suspected incipient neurocognitive disorder) and cognitively unimpaired people (CU), respectively? MethodsSpatiotemporal gait data were collected by using an electronic walkway (GAITRite®), i.e. assessments in comfortable gait speed. Using cross-sectional gait data, two principal component analyses (PCA) were performed (varimax rotation) to define different components of gait in people with MCI (n = 114) and CU (n = 219), respectively, from the BioFINDER-2 study. ResultsBoth PCAs produced four components, here called Variability, Pace/Stability, Rhythm and Asymmetry. Total variance explained was 81.0% (MCI) versus 80.3% (CU). The Variability component explained the largest amount of variance (about 25%) in both groups. The highest loading gait parameter was the same for both groups in three out of four components, i.e. step velocity variability (Variability), mean step length (Pace/Stability) and mean step time (Rhythm). In the asymmetry component, stance time asymmetry (MCI) and swing time asymmetry (CU) loaded the highest. SignificanceThe gait components seem similar in people with and without MCI, although there were some differences. This study may aid the identification of gait variables that represent different components of gait. Gait parameters such as step velocity variability, mean step length, mean step time as well as swing and stance time asymmetry could serve as interesting core variables of different gait components in future research in people with MCI (with suspected incipient neurocognitive disorder) and CU. However, the selection of gait variables depends on the purpose. It needs to be noted that assessment of variability measures requires more advanced technology than is usually used in the clinic.

Machine Learning-Based Classification of Dependence in Ambulation in Stroke Patients Using Smartphone Video Data

The goal of this study was to develop a framework to classify dependence in ambulation by employing a deep model in a 3D convolutional neural network (3D-CNN) using video data recorded by a smartphone during inpatient rehabilitation therapy in stroke patients. Among 2311 video clips, 1218 walk action cases were collected from 206 stroke patients receiving inpatient rehabilitation therapy (63.24 ± 14.36 years old). As ground truth, the dependence in ambulation was assessed and labeled using the functional ambulatory categories (FACs) and Berg balance scale (BBS). The dependent ambulation was defined as a FAC score less than 4 or a BBS score less than 45. We extracted patient-centered video and patient-centered pose of the target from the tracked target’s posture keypoint location information. Then, the extracted patient-centered video was input in the 3D-CNN, and the extracted patient-centered pose was used to measure swing time asymmetry. Finally, we evaluated the classification of dependence in ambulation using video data via fivefold cross-validation. When training the 3D-CNN based on FACs and BBS, the model performed with 86.3% accuracy, 87.4% precision, 94.0% recall, and 90.5% F1 score. When the 3D-CNN based on FACs and BBS was combined with swing time asymmetry, the model exhibited improved performance (88.7% accuracy, 89.1% precision, 95.7% recall, and 92.2% F1 score). The proposed framework for dependence in ambulation can be useful, as it alerts clinicians or caregivers when stroke patients with dependent ambulatory move alone without assistance. In addition, monitoring dependence in ambulation can facilitate the design of individualized rehabilitation strategies for stroke patients with impaired mobility and balance function.

Temporal But Not Spatial Gait Parameters Associated With Lower Balance Capacity in Moderate-High Functioning Persons With Stroke.

Falls are a major health concern after stroke. Spatial and temporal gait asymmetry and variability can contribute to instability and increased fall risk in persons with stroke (PwS). We aimed to quantify gait spatiotemporal symmetry and variability parameters in PwS undergoing rehabilitation in the subacute stage of the disease, by comparison to healthy participants, and to examine the associations between these parameters and patients' reactive and proactive balance capacity. Twenty-two PwS and 12 healthy adults walked over a computerized treadmill system at their self-selected walking speed. Symmetry and variability of gait parameters (step length, swing time, and stance time) as well as upper extremity and lower extremity angular range of motion in the sagittal plane were extracted. In addition, the Berg Balance Scale (BBS) and the fall threshold in response to sudden surface translations at increasing intensities were assessed. PwS demonstrated significantly higher asymmetry in all gait parameters in comparison to controls. Also, PwS demonstrated increased stance time variability in comparison to healthy controls and increased swing time variability in the paretic lower extremity. Significant negative associations were found between fall threshold and stance time asymmetry in PwS (r = -0.48, P = 0.022), between the BBS and swing time asymmetry (r = -0.50, P = 0.018), and between the BBS and stance time variability of the paretic lower extremity (r = -0.56, P = 0.006). Findings highlight the importance of gait temporal symmetry and variability measures for dynamic balance control after stroke. These parameters should be considered when assessing gait recovery and safety in PwS.Video Abstract available for more insight from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A355).

Changes in Walking Speed After High-Intensity Treadmill Training Are Independent of Changes in Spatiotemporal Symmetry After Stroke.

Objectives: Decreased walking speeds and spatiotemporal asymmetry both occur after stroke, but it is unclear whether and how they are related. It is also unclear whether rehabilitation-induced improvements in walking speed are associated with improvements in symmetry or greater asymmetry. High-intensity speed-based treadmill training (HISTT) is a recent rehabilitative strategy whose effects on symmetry are unclear. The purpose of this study was to: (1) assess whether walking speed is cross-sectionally associated with spatiotemporal symmetry in chronic stroke, (2) determine whether HISTT leads to changes in the spatiotemporal symmetry of walking, and (3) evaluate whether HISTT-induced changes in walking speed are associated with changes in spatiotemporal symmetry.Methods: Eighty-one participants with chronic stroke performed 4 weeks of HISTT. At pre, post, and 3-month follow-up assessments, comfortable and maximal walking speed were measured with the 10-meter walk test, and spatiotemporal characteristics of walking were measured with the GAITRite mat. Step length and swing time were expressed as symmetry ratios (paretic/non-paretic). Changes in walking speed and symmetry were calculated and the association was determined.Results: At pre-assessment, step length and swing time asymmetries were present (p < 0.001). Greater temporal symmetry was associated with faster walking speeds (p ≤ 0.001). After HISTT, walking speeds increased from pre-assessment to post-assessment and follow-up (p ≤ 0.002). There were no changes in spatiotemporal symmetry (p ≥ 0.10). Change in walking speed was not associated with change in spatial or temporal symmetry from pre- to post-assessment or from post-assessment to follow-up (R2 ≤ 0.01, p ≥ 0.37).Conclusions: HISTT improves walking speed but does not systematically improve or worsen spatiotemporal symmetry. Clinicians may need to pair walking interventions like HISTT with another intervention designed to improve walking symmetry simultaneously. The cross-sectional relation between temporal symmetry and walking speed may be mediated by other factors, and not be causative.

Walking on a Vertically Oscillating Platform with Simulated Gait Asymmetry

Asymmetric gait is associated with pain, injury, and reduced stability in patient populations. Data from side by side walking suggest that unintentional synchronization with an external cue may reduce gait asymmetry. Two types of asymmetric gait were examined here: (1) mass imbalance between limbs to simulate single limb amputation and (2) restriction of plantarflexion during toe-off to simulate reduced propulsion from neurological impairment. Twenty-five healthy participants walked normally and with simulated gait asymmetry on a custom-designed treadmill that oscillated in the vertical direction via pneumatic actuation (amplitude: 2 cm, frequency: participant’s preferred step frequency). Swing Time Asymmetry (STA) and Phase Coordination Index (PCI) both increased significantly with the application of unilateral mass and plantarflexion restriction (p &lt; 0.001). However, walking with simulated asymmetry did not alter unintentional synchronization with the treadmill motion. Further, oscillation of the treadmill did not improve STA or PCI while walking with simulated asymmetry. Analysis of synchronized step clusters using the Weibull survival function revealed that synchronization with the platform persisted for longer durations when compared with data from side by side walking. These results suggest that walking on a vertically oscillating surface may not be an effective approach for improving gait asymmetry.

Deterioration of specific aspects of gait during the instrumented 6-min walk test among people with multiple sclerosis.

Prolonged walking is typically impaired among people with multiple sclerosis (pwMS), however, it is unclear what the contributing factors are or how to evaluate this deterioration. We aimed to determine which gait features become worse during sustained walking and to examine the clinical correlates of gait fatigability in pwMS. Fifty-eight pwMS performed the 6-min walk test while wearing body-fixed sensors. Multiple gait domains (e.g., pace, rhythm, variability, asymmetry and complexity) were compared across each minute of the test and between mild- and moderate-disability patient groups. Associations between the decline in gait performance (i.e., gait fatigability) and patient-reported gait disability, fatigue and falls were also determined. Cadence, stride time variability, stride regularity, step regularity and gait complexity significantly deteriorated during the test. In contrast, somewhat surprisingly, gait speed and swing time asymmetry did not change. As expected, subjects with moderate disability (n = 24) walked more poorly in most gait domains compared to the mild-disability group (n = 34). Interestingly, a group × fatigue interaction effect was observed for cadence and gait complexity; these measures decreased over time in the moderate-disability group, but not in the mild group. Gait fatigability rate was significantly correlated with physical fatigue, gait disability, and fall history. These findings suggest that sustained walking affects specific aspects of gait, which can be used as markers for fatigability in MS. This effect on gait depends on the degree of disability, and may increase fall risk in pwMS. To more fully understand and monitor correlates that reflect everyday walking in pwMS, multiple domains of gait should be quantified.

CONTINUOUS MONITORING OF GAIT: WHAT CAN IT TELL US ABOUT DEMENTIA?

Background Gait impairment has been associated with cognitive impairment and dementia, and may reflect the conditions-specific neurodegeneration. Lab-based gait analysis is useful in predicting and aiding dementia diagnosis. However, gait laboratories are expensive and require specialist knowledge. Advances in technology have allowed body-worn sensors to provide similar information regarding gait impairment and walking activity in an individual's home and everyday environment. Continuous monitoring of gait impairment and activity is important for identification and monitoring of different types of dementia. This study aimed to assess both gait impairment and walking activity differences across dementia subtypes and controls. Methods 87 participants were recruited across three groups; 33 Alzheimer's Disease (AD;(mean±sd) Age: 78±7; MMSE: 23±4), 27 Lewy Body Dementia (LBD; Age: 78±7; MMSE: 24±3) and 27 controls (Age:74±9; MMSE: 29±1). Dementia subtypes ranged from mild cognitive impairment to moderate dementia. A tri-axial accelometer (Axivity AX3) recorded data pertaining to gait and walking activity over 7 days. One way ANOVAs and non-parametric equivalents assessed group differences. Results Preliminary results report significant gait impairments in both disease groups compared to controls for pace (step velocity, step length; (p ≤ .05)) and asymmetry (step, stance and swing time asymmetry (p ≤ .05); Figure 1). LBD alone were more variable in gait (step, stance, swing time and step velocity variability; (p ≤ .05)) compared to both AD and controls. People with LBD were also more variable than AD for step velocity (p = .021) and step length variability (p= .041). LBD spent less time walking compared to controls and AD (p ≤ .05; Figure 2). AD took fewer average steps per day compared to controls (p=.019). LBD and AD were less variable in their walking bouts, and LBD performed a greater proportion of shorter walking bouts (higher alpha) compared to controls. Conclusions Body-worn sensors provide an individualised representation of gait with information about discrete characteristics of gait impairment and changes in walking activity across all stages of cognitive impairment. This is important for both diagnostic and interventional purposes. Future research should aim to establish effects of environmental context on gait in free-living conditions to refine clinical interpretation.

Effects of Subthalamic and Nigral Stimulation on Gait Kinematics in Parkinson’s Disease

Conventional subthalamic deep brain stimulation for Parkinson’s disease (PD) presumably modulates the spatial component of gait. However, temporal dysregulation of gait is one of the factors that is tightly associated with freezing of gait (FOG). Temporal locomotor integration may be modulated differentially at distinct levels of the basal ganglia. Owing to its specific descending brainstem projections, stimulation of the substantia nigra pars reticulata (SNr) area might modulate spatial and temporal parameters of gait differentially compared to standard subthalamic nucleus (STN) stimulation. Here, we aimed to characterize the differential effect of STN or SNr stimulation on kinematic gait parameters. We analyzed biomechanical parameters during unconstrained over ground walking in 12 PD patients with subthalamic deep brain stimulation and FOG. Patients performed walking in three therapeutic conditions: (i) Off stimulation, (ii) STN stimulation (alone), and (iii) SNr stimulation (alone). SNr stimulation was achieved by stimulating the most caudal contact of the electrode. We recorded gait using three sensors (each containing a tri-axial accelerometer, gyroscope, and magnetometer) attached on both left and right ankle, and to the lumbar spine. STN stimulation improved both the spatial features (stride length, stride length variability) and the temporal parameters of gait. SNr stimulation improved temporal parameters of gait (swing time asymmetry). Correlation analysis suggested that patients with more medial localization of the SNr contact associated with a stronger regularization of gait. These results suggest that SNr stimulation might support temporal regularization of gait integration.

Predicting first fall in newly diagnosed Parkinson's disease: Insights from a fall-naïve cohort.

Falls are common and associated with reduced independence and mortality in Parkinson's disease. Previous research has been conducted on falls-prevalent or advanced disease cohorts. This study identifies risk factors for first fall for 36 months in a newly diagnosed, falls-naïve cohort. A total of 121 consecutive Parkinson's disease patients were recruited. Falls data were collected prospectively during 36 months from diagnosis via monthly falls diaries and telephone follow-up for 117 participants. Assessment comprised a comprehensive battery of clinical, gait, and cognitive measures. Significant predictors were identified from decision-tree analysis and survival analysis with time to first fall during 36 months as the dependent variable. At baseline, 26 (22%) participants reported retrospective falls. At 36 months, the remaining cohort (n = 91) comprised 47 fallers (52%) and 30 (33%) nonfallers and 14 (15%) participants with incomplete diaries. Fallers presented with a significantly higher disease severity, poorer ability to stand on one leg, slower gait speed, increased stance time variability, and higher swing time asymmetry. Median time to first fall was 847 days. Gait speed, stance time, and Hoehn & Yahr III stage emerged as significant predictors of first fall, hazard ratio 3.44 (95% confidence interval [CI] 1.58 to 7.48), 3.31(95% CI 1.40 to 7.80), and 2.80 (95% CI 1.38 to 5.65), respectively. The hazard ratio for risk factors combined was 7.82 (CI 2.80 to 21.84). Interventions that target gait deficit and postural control in early Parkinson's disease may limit the potential for first fall. © 2016 International Parkinson and Movement Disorder Society.

Relationships between gait and standing balance in hemiplegia

Objective To study the relationships between the standing balance and walking ability of hemiplegic stroke survivors. Methods Eighty-eight post-stroke hemiplegic patients who could walk independently for more than 10 metres were selected into a patient group, while 88 healthy counterparts were recruited into a control group. Descriptors of the gait and balance function of both groups were collected using a gait and balance training and evaluation apparatus (Model: AL-600). The gait parameters were step width, walking speed, step length asymmetry (SLA), swing time asymmetry (SWTA) and stand time asymmetry (STA). The balance parameters studied were total trajectory length of the center of plantar pressure (COPD), the average left and right deviation of the center of plantar pressure (COPD-X) and the average anterio-posterior deviation of the center of plantar pressure (COPD-Y). Differences in indexes of gait and balance function between the two groups were analyzed using t-tests, and the relationships between the gait and balance indicators were analyzed using Pearson correlation coefficients. Results The walking speed, step width, COPD, COPD-X, COPD-Y, SLA, SWTA and STA of the patient group[(37.64±18.29)cm/s, (14.45±4.17)cm, (66.75±29.04)cm, (2.04±1.41)cm, (2.48±1.28)cm, (1.30±0.46), (1.65±0.67) and (1.18±0.16), respectively]all increased significantly more compared to the control group[(90.76±14.72)cm/s, (8.70±2.62)cm, (27.84±6.54)cm, (1.30±0.53)cm, (1.68±0.40)cm, (1.07±0.06), (1.07±0.08) and (1.05±0.06), respectively], though the walking speed was significantly slower than that in the control group (P<0.05). The patient group's average COPD-X showed slightly and moderately negative correlation with their walking speed, step width, SLA and SWTA (P<0.05). COPD-Y was weakly related with step width (P<0.05). Conclusion The standing balance of hemiplegic patients after stroke is related to their walking speed, step width and gait asymmetry. Especially significant correlation is observed between standing balance parameters such as COPD-X and gait parameters. Key words: Stroke; Balance control; Step width; Walking speed; Center of plantar pressure

Plantar tactile perturbations enhance transfer of split-belt locomotor adaptation.

Patterns of human locomotion are highly adaptive and flexible and depend on the environmental context. Locomotor adaptation requires the use of multisensory information to perceive altered environmental dynamics and generate an appropriate movement pattern. In this study, we investigated the use of multisensory information during locomotor learning. Proprioceptive perturbations were induced by vibrating tactors, placed bilaterally over the plantar surfaces. Under these altered sensory conditions, participants were asked to perform a split-belt locomotor task representative of motor learning. Twenty healthy young participants were separated into two groups: no-tactors (NT) and tactors (TC). All participants performed an overground walking trial, followed by treadmill walking including 18 min of split-belt adaptation and an overground trial to determine transfer effects. Interlimb coordination was quantified by symmetry indices and analyzed using mixed repeated-measures ANOVAs. Both groups adapted to the locomotor task, indicated by significant reductions in gait symmetry during the split-belt task. No significant group differences in spatiotemporal and kinetic parameters were observed on the treadmill. However, significant group differences were observed overground. Step and swing time asymmetries learned on the split-belt treadmill were retained and decayed more slowly overground in the TC group whereas in NT, asymmetries were rapidly lost. These results suggest that tactile stimulation contributed to increased lower limb proprioceptive gain. High proprioceptive gain allows for more persistent overground after effects, at the cost of reduced adaptability. Such persistence may be utilized in populations displaying pathologic asymmetric gait by retraining a more symmetric pattern.

Walking Speed and Step Length Asymmetry Modify the Energy Cost of Walking After Stroke

Background. A higher energy cost of walking poststroke has been linked to reduced walking performance and reduced participation in the community. Objective. To determine the contribution of postintervention improvements in walking speed and spatiotemporal gait asymmetry to the reduction in the energy cost of walking after stroke. Methods. In all, 42 individuals with chronic hemiparesis (>6 months poststroke) were recruited to participate in 12 weeks of walking rehabilitation. The energy cost of walking, walking speed, and step length, swing time, and stance time asymmetries were calculated pretraining and posttraining. Sequential regression analyses tested the cross-sectional (ie, pretraining) and longitudinal (ie, posttraining changes) relationships between the energy cost of walking versus speed and each measure of asymmetry. Results. Pretraining walking speed (β = −.506) and swing time asymmetry (β = .403) predicted pretraining energy costs: adjR2 = 0.713; F(3, 37) = 34.05; P < .001. In contrast, change in walking speed (β = .340) and change in step length asymmetry (β = .934) predicted change in energy costs with a significant interaction between these independent predictors: adjR2 = 0.699; F(4, 31) = 21.326; P < .001. Moderation by the direction or the magnitude of pretraining asymmetry was not found. Conclusions. For persons in the chronic phase of stroke recovery, faster and more symmetric walking after intervention appears to be more energetically advantageous than merely walking faster or more symmetrically. This finding has important functional implications, given the relationship between the energy cost of walking and community walking participation.

Gait asymmetry and balance in hemiplegic stroke survivors

Objective To explore any correlation between gait asymmetry and the balance of hemiplegic stroke survivors.Methods Thirty patients with hemiplegia caused by stroke but who could walk more than 10 metres independently were recruited as the experimental group; 30 age-matched healthy elderly people served as the control group.An AL-600 gait analyzer was used to quantify the spatial and temporal gait parameters of all subjects.Gait asymmetry ratios were calculated.The 30 stroke patients were also assessed with the Berg balance scale (BBS).Two independent sample t-tests were used to compare the step length asymmetry (SLA),swing time asymmetry (SWTA) and STA (stance time asymmetry) ratios for the two groups and their average step widths.Pearson correlation coefficients were calculated relating the SLA,SWTA,STA,step width and BBS results.Results Among the experimental group,swing time and step length on the affected side were significantly different from the unaffected side,and stance time on the affected side was significantly shorter.The control group showed no such significant differences.All of the experimental group's average asymmetry ratios were significantly greater than those of the control group,as was their step width.Step width and BBS score were negative correlated,but step width was positively correlated with the step length and swing time asymmetry ratios.BBS scores were negatively correlated with the step length and swing time asymmetry ratios.Stance time asymmetry and step width showed no significant correlation with the BBS scores.Conclusion The gait of hemiplegic stroke patients is both spatially and temporally asymmetric,and a certain correlation exists between the degree of asymmetry and balance function. Key words: Stroke; Gait; Gait asymmetry; Balance; Hemiplegia

The Relationship Between Spatiotemporal Gait Asymmetry and Balance in Individuals With Chronic Stroke

Falls are common after stroke and often attributed to poor balance. Falls often occur during walking, suggesting that walking patterns may induce a loss of balance. Gait after stroke is frequently spatiotemporally asymmetric, which may decrease balance. The purpose of this study is to determine the relationship between spatiotemporal gait asymmetry and balance control. Thirty-nine individuals with chronic stroke walked at comfortable and fast speeds to calculate asymmetry ratios for step length, stance time, and swing time. Balance measures included the Berg Balance Scale, step width during gait, and the weight distribution between legs during standing. Correlational analyses determined the relationships between balance and gait asymmetry. At comfortable and fast gait speeds, step width was correlated with stance time and swing time asymmetries (r = 0.39-0.54). Berg scores were correlated with step length and swing time asymmetries (r = -0.36 to -0.63). During fast walking, the weight distribution between limbs was correlated with stance time asymmetry (r = -0.41). Spatiotemporal gait asymmetry was more closely related to balance measures involving dynamic tasks than static tasks, suggesting that gait asymmetry may be related to the high number of falls poststroke. Further study to determine if rehabilitation that improves gait asymmetry has a similar influence on balance is warranted.

Effects of Prosthetic Mass Distribution on Metabolic Costs and Walking Symmetry

Unilateral, transtibial amputees exhibit walking asymmetries and higher metabolic costs of walking than nonamputees walking at similar speeds. Using lightweight prostheses has previously been suggested as a contributing factor to walking asymmetries. The purpose was to investigate the effects of prosthesis mass and mass distribution on metabolic costs and walking asymmetries among six unilateral, transtibial amputees. Kinematic and temporal symmetry did not improve when mass was added at different locations on the limb. Stance and swing time asymmetries increased by 3.4% and 7.2%, respectively, with loads positioned distally on the limb. Maximum knee angular velocity asymmetries increased by 6% with mass added to the thigh, whereas maximum thigh angular velocity asymmetries increased by approximately 10% with mass positioned near the prosthetic ankle. Adding 100% of the estimated mass difference between intact and prosthetic legs to the ankle of the prosthesis increased energy costs of walking by 12%; adding the same mass to the prosthesis center of mass or thigh center of mass increased metabolic cost by approximately 7% and 5%, respectively. Unless other benefits are gained by increasing prosthesis mass, this should not be considered as a possible alternative to current lightweight prosthesis designs currently being prescribed to unilateral amputees.

Reliability of Spatiotemporal Asymmetry During Overground Walking for Individuals Following Chronic Stroke

Rehabilitation research for individuals with chronic stroke is increasingly addressing spatiotemporal asymmetries (STA). Understanding the reliability of STA between sessions is essential for determining whether treatment responses exceed day-to-day variation. The purpose of this study was to determine the minimal detectable change (MDC) and test-retest reliability in STA and gait speed measures for individuals with chronic stroke. Twenty-six individuals with chronic (>6 months) stroke participated in 2 visits. At each visit, participants walked across a 14-ft (4.3-m) GAITRite mat at comfortable gait speed (CGS) and fast gait speed (FGS). Spatiotemporal asymmetries ratios (paretic/nonparetic limb) were calculated for step length, stance time, and swing time. Intraclass correlation coefficients (ICC, 2,1) were calculated to determine reliability between sessions. Minimal detectable change values were calculated to determine the smallest change that is considered "real." Spatiotemporal asymmetry measures were consistent between sessions, with ICCs ranging from 0.93 to 0.98. Asymmetry ratio MDC values were calculated for step length (CGS: 0.15; FGS: 0.19), swing time (CGS: 0.26; FGS: 0.20), and stance time (CGS: 0.09; FGS: 0.10). Gait speed MDC was 0.20 m/s and 0.22 m/s, respectively, for the CGS and FGS walking conditions. There were considerable differences among MDC values for the various STA measures, suggesting that larger changes will be necessary to show improvement for certain measures (eg, swing time asymmetry). These data will assist with setting clinical goals for patients with chronic stroke and will be useful for evaluating interventions designed to minimize temporal and spatial interlimb asymmetries during walking.