Changes In Walking Velocity Research Articles

Approaching Process in Walking through an Aperture for Individuals with Stroke

Muroi et al. show that individuals with stroke have improved collision avoidance behavior when passing through an aperture while entering from the paretic-side of the body. However, the underlying mechanism remains unknown. We reanalyzed Muroi et al.’s data to reveal how individuals with stroke walk through an aperture by examining changes in walking velocity and behavioral complexity (i.e., sample entropy, an index of (ir)regularity of time series, regarded lower entropy as more regular and less complex) by focusing on the approaching process. The results showed that individuals with stroke reduced their walking velocity and behavioral complexity before passing through the narrow aperture when approaching from the paretic side. We interpreted that the improved obstacle avoidance when penetrating from the paretic side may be due to careful body rotation and adjusting the walking velocity in advance.

Changes in walking velocity and stride parameters with age in children with Charcot-Marie-Tooth disease

The purpose of this study is to assess how Charcot-Marie-Tooth disease, a group of inherited peripheral neuropathies that result in distal weakness, affects walking velocity over time in comparison to age-matched controls. Comprehensive gait analysis of 57 children (mean age 12.0, SD 3.7 years) compared to 76 age-matched controls (mean age 10.1, SD 3.4 years) demonstrated slower walking velocity (p<0.001) due to both shorter stride length (p<0.001) and diminished cadence (p=0.01). There was higher walking velocity (p<0.001), stride length (p=0.002) and cadence (p<0.001) in patients with dorsiflexor strength ≥3 and higher walking velocity (p=0.001) and cadence (p=0.03) in patients plantar flexor strength ≥4. Analysis of Charcot-Marie-Tooth type 1 and type 2 subgroups showed that walking velocity increased significantly with age in controls (p=0.001) but did not increase in children with either subtype (p>0.54). Stride length increased significantly with age in all groups (p<0.001) but at a slower rate in type 1 and 2 compared to controls. These differences contributed to increasing deficits in walking velocity and stride length with age in type 1 and 2 in comparison to controls, with deficits appearing earlier in type 2. Since the slower walking velocity in children with Charcot-Marie-Tooth disease is primarily due to short stride length, treatments that enable improved stride length, such as plantar flexor strengthening and bracing, may improve walking velocity and associated gait function.

Effects Of A 12-week Self-managed Exercise Program On Fatigability In Older Adults

Aging is associated with greater fatigability and reduced participation in physical activity. Exercise training in older adults has been associated with a number of health benefits; however, less is known about the effects of self-managed exercise on perceived and performance fatigability. PURPOSE: Compare the effects of a 12-week self-managed exercise program on perceived (PercF) and performance (PerfF) fatigability in a group of unimpaired older adults. METHODS: 28 older adults participated in a self-managed exercise program (15 men and 13 women; age 71.3 ± 4.2 years). The program consisted of educational lectures on aerobic (AT), resistance (RT), and balance (BT) training methods as described by the National Institute of Aging. 17 adults completed the 12-week program in three exercise groups: AT only (n=8), AT/RT (n=5), and AT/RT/BT (n=4). Fatigability was assessed following a standardized 10-minute walk test at a self-selected speed at baseline (PRE) and at the conclusion of the 12-week exercise program (POST). PercF was calculated at the completion of walking by dividing participant-perceived changes in fatigue by the total distance walked in meters. PerfF was calculated as the change in walking velocity (at 2.5 and 10 minutes), divided by the total distance walked. Within-group data were analyzed with a paired t-test and between-group effects using one-way ANOVA. RESULTS: Within the AT and AT/RT groups, significantly lower PerfF was observed at POST (p = .011 and p = .035, respectively) with no differences found in the AT/RT/BT group (p = .437). PercF was unchanged in all groups (AT, p = .50, AT/RT, p = .65, AT/RT/BT, p = .70). No difference was observed between groups for PercF (F (2,14) = 0.443, p = .651) or PerfF (F (2,14) =. 528, p = .601). Further, Cohen’s effect size for changes in PerfF was moderate for AT (d = .48), AT/RT (d = .38), and AT/RT/BT (d =. 38). CONCLUSIONS: Participation in a 12-week self-managed exercise program reduced performance fatigability in unimpaired older adults. However, our results did not reveal specific exercise recommendations for older adults to improve both performance and perceived fatigability. Future studies are needed to investigate the influence of exercise training on measures of fatigability to optimize exercise interventions.

The Relationship Between Balance Confidence and Cognitive Motor Interference in Individuals With Multiple Sclerosis

ABSTRACTGait and cognitive impairments are compounded when performed simultaneously in individuals with multiple sclerosis (MS), and this is termed cognitive-motor interference (CMI). The authors examined whether CMI is related to balance confidence in individuals with MS. They hypothesized that individuals with low balance confidence would exhibit greater CMI possibly indicating a behavioral modification during dual task conditions. Thirty-four individuals with MS completed Activity-specific Balance Confidence (ABC) scale and a cognitive assessment as well as single and dual task walking trials at a comfortable pace. CMI was calculated as the percent change in walking velocity and cognitive task performance from single- to dual-task conditions and termed dual-task cost (DTC). A correlation analysis was performed to determine the relationships between DTCs of gait and cognitive performance and ABC scores. The correlation analysis revealed no significant association between ABC and DTC of walking velocity (p > .05). A significant relationship between balance confidence and DTCs of cognition was observed. The observed relationships suggest individuals with MS tend to alter their cognitive performance rather than manipulating their gait when confronted with a dual task. Overall, the findings partially support a behavioral explanation of CMI in individuals with MS.

Mobility and cognitive correlates of dual task cost of walking in persons with multiple sclerosis

Background: Persons with multiple sclerosis (MS) often experience a decrease in walking performance while simultaneously performing a cognitive task. This decrease in walking performance is termed dual task cost (DTC). Objective: To examine if mobility and cognitive function are correlates of DTC in persons with MS. Methods: Participants were 96 persons with MS who had Expanded Disability Status Scale scores that ranged between 2.0 and 6.5. To determine DTC, participants walked at a self-selected pace with and without a cognitive task while gait velocity was recorded. The effect of the cognitive task was quantified as the percent change in walking velocity between conditions. Participants further completed the timed 25-foot walk (T25FW) and Symbol Digit Modalities Test (SDMT). Centered scores for the T25FW and SDMT, and the product of the center scores, were placed into a linear regression to determine the correlates of DTC. Results: DTC averaged 12.5% (SD = 9.3) and ranged between −14.1 and 42.4%. Performance on the T25FW ranged between 3.1 and 24.5 s with an average of 6.8 s (SD = 3.1 s). SDMT scores ranged between 15 and 79 with an average of 45 items (SD = 12). Regression analysis revealed that age, disability, walking and cognitive performance explained 17% of the variance in DTC. The interaction between walking and cognition did not explain additional variance. Conclusions: Mobility and cognitive impairment were both independent predictors of DTC of walking in persons with MS. This raises the possibility that DTC could be reduced with modifications of either mobility or cognition.Implications for RehabilitationPersons with multiple sclerosis (MS) demonstrate a significant decrease in walking speed when engaged in a simultaneous cognitive task (e.g. dual task cost).Both walking and cognitive performance were related to dual task cost of walking in persons with MS.Improvements in walking could translate into potential improvements of dual task cost and have functional implications in persons with MS.

Exercise dose and mobility outcome in a comprehensive stroke unit: Description and prediction from a prospective cohort study

To describe the dose of lower limb exercise completed during admission to a stroke unit, establish predictors of dose and explore the relationship between dose and walking outcomes. Inception cohort study. Two hundred consecutively-admitted people with stroke. Repetitions of exercise completed throughout the admission were tallied. Possible predictors of exercise dose were recorded within 48 h of admission. Walking velocity was assessed at the beginning and end of the hospital stay. Data were available for 191 (96%) participants on discharge. The mean daily dose of lower limb exercise was 288 repetitions (standard deviation (SD) 242), the variability in dose was best explained by age and disability level. The mean improvement in walking velocity was 0.43 m/s (SD 0.46), 26% of variability in walking improvement was explained by exercise repetitions and 29% was explained by a multivariable model including significant contributions from exercise repetitions (p < 0.01) and age (p = 0.03). After controlling for other factors, for every 100 daily repetitions of lower limb exercise there was an additional change in walking velocity of 0.08 m/s (95% CI 0.05 to 0.11, p < 0.01). Exercise dose in a stroke unit is variable and can be predicted by age and disability. Increased exercise dose is associated with improved mobility outcomes.

Quantification of Uhthoff's phenomenon in multiple sclerosis: a magnetic stimulation study

Objective: To quantify temperature induced changes (=Uhthoff phenomenon) in central motor conduction and their relation to clinical motor deficits in 20 multiple sclerosis (MS) patients. Methods: Self-assessment of vulnerability to temperature and clinical examination were performed. We used motor evoked potentials to measure central motor conduction time (CMCT) and applied the triple stimulation technique (TST) to assess conduction failure. The TST allows an accurate quantification of the proportion of conducting central motor neurons, expressed by the TST amplitude ratio (TST-AR). Results: Temperature induced changes of TST-AR were significantly more marked in patients with prolonged CMCT ( P=0.037). There was a significant linear correlation between changes of TST-AR and walking velocity ( P=0.0002). Relationships were found between pronounced subjective vulnerability to temperature and (i) abnormal CMCT ( P=0.02), (ii) temperature induced changes in TST-AR ( P=0.04) and (iii) temperature induced changes in walking velocity ( P=0.04). CMCT remained virtually unchanged by temperature modification. Conclusions: Uhthoff phenomena in the motor system are due to varying degrees of conduction block and associated with prolonged CMCT. In contrast to conduction block, CMCT is not importantly affected by temperature. Significance: This is the first study quantifying the Uhthoff phenomenon in the pyramidal tract of MS patients. The results suggest that patients with central conduction slowing are particularly vulnerable to develop temperature-dependent central motor conduction blocks.

Temporospatial parameters of gait after obturator neurolysis in patients with spasticity.

The management of spasticity should be implemented with the most appropriate pharmacologic agents. Ideally, these agents should provide functional improvement with minimal adverse effects. The aim of this study was to evaluate the width of the base of support and the velocity of gait before and after obturator nerve block. Blocks were performed with aqueous phenol solution in patients with unilateral hip adductor muscle overactivity that resulted in scissoring gait. The goal was to analyze functional improvement and quantify outcomes and to attempt to document adverse effects. This retrospective study analyzed data from 24 patients' files. Inclusion criteria included subjects whose main functional complaint was an adducted gait pattern. All subjects were able to consent for and to undergo unilateral obturator neurolysis with 7% phenol solution. Temporospatial parameters of gait were obtained using the Gait Mat II before and after obturator nerve injection. The analysis showed no statistical change in the walking velocity or step length. However, the width of the base of support was significantly increased after injection. No postblock complications were reported. Obturator neurolysis with 7% phenol solutions is an effective procedure to decrease hip adductor muscle overactivity without reported complications. In the studied population, improvement was found in the width of the base of support without immediate change in walking velocity or step length.

Resonant frequencies of arms and legs identify different walking patterns

The present study is aimed at investigating changes in the coordination of arm and leg movements in young healthy subjects. It was hypothesized that with changes in walking velocity there is a change in frequency and phase coupling between the arms and the legs. In addition, it was hypothesized that the preferred frequencies of the different coordination patterns can be predicted on the basis of the resonant frequencies of arms and legs with a simple pendulum model. The kinematics of arms and legs during treadmill walking in seven healthy subjects were recorded with accelerometers in the sagittal plane at a wide range of different velocities (i.e., 0.3–1.3 m/s). Power spectral analyses revealed a statistically significant change in the frequency relation between arms and legs, i.e., within the velocity range 0.3–0.7 m/s arm movement frequencies were dominantly synchronized with the step frequency, whereas from 0.8 m/s onwards arm frequencies were locked onto stride frequency. Significant effects of walking speed on mean relative phase between leg and arm movements were found. All limb pairs showed a significantly more stable coordination pattern from 0.8 to 1.0 m/s onwards. Results from the pendulum modelling demonstrated that for most subjects at low-velocity preferred movement frequencies of the arms are predicted by the resonant frequencies of individual arms (about 0.98 Hz), whereas at higher velocities these are predicted on the basis of the resonant frequencies of the individual legs (about 0.85 Hz). The results support the above-mentioned hypotheses, and suggest that different patterns of coordination, as shown by changes in frequency coupling and phase relations, can exist within the human walking mode.

Visual influence on human locomotion. Modulation to changes in optic flow.

The effect of an optic flow pattern on human locomotion was studied in subjects walking on a self-driven treadmill. During walking an optic flow pattern was presented, which gave subjects the illusion of walking in a tunnel. Visual stimulation was achieved by a closed-loop system in which optic flow and treadmill velocity were automatically adjusted to the intended walking velocity (WV). Subjects were instructed to keep their WV constant. The presented optic flow velocity was sinusoidally varied relative to the WV with a cycle period of 2 min. The independent variable was the relative optic flow (rOF), ranging from -1, i.e., forward flow of equal velocity as the WV, and 3, i.e., backward flow 3 times faster than WV. All subjects were affected by rOF in a similar way. The results showed, firstly, an increase in stride-cycle variability that suggests a larger instability of the walking pattern than in treadmill walking without optic flow; and, secondly, a significant modulating effect of rOF on the self-chosen WV. Backward flow resulted in a decrease, whereas forward flow induced an increase of WV. Within the analyzed range, a linear relationship was found between rOF and WV. Thirdly, WV-related modulations in stride length (SL) and stride frequency (SF) were different from normal walking: whereas in the latter a change in WV is characterized by a stable linear relationship between SL and SF (i.e., an approximately constant SL to SF ratio), optic flow-induced changes in WV are closely related to a modulation of SL (i.e., a change of SL-SF ratio). Fourthly, this effect of rOF diminished by about 45% over the entire walking distance of 800 m. The results suggest that the adjustment of WV is the result of a summation of visual and leg-proprioceptive velocity informations. Visual information about ego-motion leads to an unintentional modulation of WV by affecting specifically the relationship between SL and SF. It is hypothesized that the space-related parameter (SL) is influenced by visually perceived motion information, whereas the temporal parameter (SF) remains stable. The adaptation over the entire walking distance suggests that a shift from visual to leg-proprioceptive control takes place.

Predictors of change in walking velocity in older adults.

To determine factors that predict change in walking velocity in older people using a multivariate model. Longitudinal observational study. A total of 588 persons older than age 60, including subjects residing in a continuing care retirement community (CCRC) (n = 248), and homebound (n = 79) and ambulatory (n = 261) subjects. Mean age at baseline = 77. Independent variables included demographics, physician measures of lower-extremity joint impairment and other musculoskeletal and neurological variables, comorbidities derived from physical examination and chart abstract, self-assessed arthritis pain, depression, and anxiety. The major dependent variables were 2- and 4-year decline in walking velocity below a threshold associated with nursing home placement. From baseline to Year 4, median walking velocity declined from 61.8 to 53.0 m/min, and the proportion of subjects above a threshold value of 11.5 m/min declined from 95.3% to 80.4%. Age, joint impairment, and weakness of quadriceps, measured at baseline, predicted 2-year and 4-year decline in walking velocity. The findings indicate that joint impairment and quadriceps strength contribute significantly to crossing a clinically significant threshold in walking velocity among older people over time. Future research is needed to determine whether these risk factors can be modified through preventive interventions such as muscle-strengthening exercises and pain medication.

Hip and ankle walking strategies: effect on peak plantar pressures and implications for neuropathic ulceration.

Treatment of neuropathic plantar ulcers often is directed at reducing excessive, repeated peak plantar pressures (PPP). The purposes of this study were to determine whether instructing a subject to walk using a hip strategy would reduce forefoot PPP and change the kinematics of walking during a single session of testing. Thirteen subjects, 7 with peripheral neuropathy and a history of a recent plantar ulcer, and 6 controls participated. PPPs were measured with an in-shoe pressure monitoring system. Kinematics were measured with a computer-assisted motion analysis system. After data were collected as subjects walked using their normal walking pattern, subjects were instructed to walk using the hip strategy by decreasing their push-off, pulling their leg forward from their hips, decreasing step length, and maintaining their normal walking velocity. Compared with using the normal (ankle) strategy, using the hip strategy showed a significant 27% decrease in forefoot PPP and a 24% increase in heel PPP. Kinematic changes were decreased plantar flexion angular velocity, hip extension range-of motion (ROM), and step length, increased dorsiflexion ROM, and hip flexion ROM, but no change in walking velocity. These findings indicate that a change in walking pattern can result in lower forefoot PPP during a single session. Assuming patients can maintain the alterations in their walking pattern, these adaptations may help to heal plantar ulcers in some patients with peripheral neuropathy.