Normal Gait Speed Research Articles

Part 2: Abstracts of posters

Vallée M, McFadyen BJ, Swaine B, Doyon J, Cantin J-F, Dumas D. Effects of environmental demands on locomotion after traumatic brain injury.To determine the effects of increasingly demanding environments related to simultaneous visual tasks and physical obstructions on the locomotor ability of people with traumatic brain injury (TBI).Group comparison study.Gait analysis laboratory within a postacute rehabilitation facility.Volunteer sample of 9 people (8 men, 1 woman; age, 39.3±13.0y) with moderate to severe TBI and a comparison group of 9 subjects without neurologic problems matched for age and sex (8 men, 1 woman; age, 39.7±12.3y).Not applicable.Reading times for the Stroop bar and Stroop word tasks, walking speeds, stride lengths, and obstacle clearance margin.The TBI group was slower than the control group in performing the Stroop bar task during sitting (P=.002), and while avoiding the narrow obstacle (P=.05), and in performing the Stroop word task while avoiding the wide obstacle (P=.019). Despite their relatively normal gait speeds on level ground, subjects with TBI walked more slowly than control subjects for the narrow (P=.024) and the wide (P=.019) obstacle conditions and for the most complex dual task (P=.042). Greater lead-limb clearance margins were observed for the TBI group than for control subjects for all conditions whereas no differences were found for the trail limb except at the far end of the wide obstacle.Despite their good recovery of locomotor function, with respect to normal level walking speeds and ability to avoid obstacles, subjects with moderate and severe TBI showed residual deficits in relation to greater difficulties in dealing with environments that challenge their locomotor and attentional abilities. The use of such naturally based dual tasks may help identify some of the environmental obstructions to social participation after TBI.

Effects of Environmental Demands on Locomotion After Traumatic Brain Injury

Vallée M, McFadyen BJ, Swaine B, Doyon J, Cantin J-F, Dumas D. Effects of environmental demands on locomotion after traumatic brain injury. Objective To determine the effects of increasingly demanding environments related to simultaneous visual tasks and physical obstructions on the locomotor ability of people with traumatic brain injury (TBI). Design Group comparison study. Setting Gait analysis laboratory within a postacute rehabilitation facility. Participants Volunteer sample of 9 people (8 men, 1 woman; age, 39.3±13.0y) with moderate to severe TBI and a comparison group of 9 subjects without neurologic problems matched for age and sex (8 men, 1 woman; age, 39.7±12.3y). Interventions Not applicable. Main Outcome Measures Reading times for the Stroop bar and Stroop word tasks, walking speeds, stride lengths, and obstacle clearance margin. Results The TBI group was slower than the control group in performing the Stroop bar task during sitting ( P=.002), and while avoiding the narrow obstacle ( P=.05), and in performing the Stroop word task while avoiding the wide obstacle ( P=.019). Despite their relatively normal gait speeds on level ground, subjects with TBI walked more slowly than control subjects for the narrow ( P=.024) and the wide ( P=.019) obstacle conditions and for the most complex dual task ( P=.042). Greater lead-limb clearance margins were observed for the TBI group than for control subjects for all conditions whereas no differences were found for the trail limb except at the far end of the wide obstacle. Conclusions Despite their good recovery of locomotor function, with respect to normal level walking speeds and ability to avoid obstacles, subjects with moderate and severe TBI showed residual deficits in relation to greater difficulties in dealing with environments that challenge their locomotor and attentional abilities. The use of such naturally based dual tasks may help identify some of the environmental obstructions to social participation after TBI.

Too much or too little step width variability is associated with a fall history in older persons who walk at or near normal gait speed

BackgroundDecreased gait speed and increased stride time, stride length, double support time, and stance time variability have consistently been associated with falling whereas step width variability has not been strongly related to falls. The purpose was to examine the linear and nonlinear associations between gait variability and fall history in older persons and to examine the influence of gait speed.MethodsGait characteristics and fall history were obtained in 503 older adults (mean age = 79; 61% female) participating in the Cardiovascular Health Study who could ambulate independently. Gait characteristics were recorded from two trials on a 4 meter computerized walkway at the subject's self-selected walking speed. Gait variability was calculated as the coefficient of variation. The presence of a fall in the past 12 months was determined by interview. The nonlinear association between gait variability and fall history was examined using a simple three level classification derived from the distribution of the data and from literature based cut-points. Multivariate logistic regression was used to examine the association between step width variability (extreme or moderate) and fall history stratifying by gait speed (1.0 m/s) and controlling for age and gender.ResultsStep length, stance time, and step time variability did not differ with respect to fall history (p > .33). Individuals with extreme step width variability (either low or high step width variability) were more likely to report a fall in the past year than individuals with moderate step width variability. In individuals who walked ≥ 1.0 m/s (n = 281), after controlling for age, gender, and gait speed, compared to individuals with moderate step width variability individuals with either low or high step width variability were more likely to have fallen in the past year (OR and 95% CI 4.38 [1.79–10.72]). The association between step width variability and fall history was not significant in individuals who walked < 1.0 m/s (n = 224).ConclusionExtreme (either too little or too much) step width variability is associated with falls in the past year in older persons who walk at or near normal gait speed and not in older persons who walk slowly (<1.0 m/s).

Association of Physical Performance Measures With Bone Mineral Density in Postmenopausal Women

Lindsey C, Brownbill RA, Bohannon RA, Ilich JZ. Association of physical performance measures with bone mineral density in postmenopausal women. Arch Phys Med Rehabil 2005;86:1102–7. Objective To investigate the association between physical performance measures and bone mineral density (BMD) in older women. Design Cross-sectional analysis. Setting University research laboratory. Participants Healthy postmenopausal women (N=116; mean age ± standard deviation, 68.3±6.8y) in self-reported good health who were not taking medications known to affect bone, including hormone replacement therapy. Interventions Not applicable. Main Outcome Measures Anthropometrics and BMD of the hip, spine, whole body, and forearm. Physical performance measures included normal and brisk 8-m gait speed, normal step length (NSL), brisk step length (BSL), timed 1-leg stance (OLS), timed sit-to-stand (STS), and grip strength. Results NSL, BSL, normal gait speed, brisk gait speed, OLS, and grip strength correlated significantly with several skeletal sites ( r range, .19–.38; P<.05). In multiple regression models containing body mass index, hours of total activity, total calcium intake, and age of menarche, NSL, BSL, normal and brisk gait speeds, OLS, and grip strength were all significantly associated with BMD of various skeletal sites (adjusted R 2 range, .11–.24; P<.05). Analysis of covariance showed that subjects with longer step lengths and faster normal and brisk gait speeds had higher BMD at the whole body, hip, and spine (brisk speed only). Those with a longer OLS had greater femoral neck BMD, and those with a stronger grip strength had greater BMD in the whole body and forearm ( P<.05). STS was not related to any skeletal site. Conclusions Normal and brisk gait speed, NSL, BSL, OLS, and grip strength are all associated with BMD at the whole body, hip, spine, and forearm. Physical performance evaluation may help with osteoporosis prevention and treatment programs for postmenopausal women when bone density scores have not been obtained or are unavailable.

Accuracy Of An Electronic Pedometer At Three Different Self-selected Walking Speeds

The use of pedometers has become a popular and inexpensive way to promote physical activity by individuals to track their steps throughout various daily activities. However, previous research has suggested that pedometers may undercount the number of steps actually walked by approximately thirty seven percent in healthy adults. Older adults or individuals with a disability may have either decreased gait speeds and/or altered gait patters which may further affect the ability of pedometers to accurately count steps. PURPOSE To compare the accuracy of a single brand of pedometer over three different self-selected gait speeds: fast, comfortable, and slow. METHODS A convenience sample of students and faculty at Concordia University Wisconsin were recruited for participation. Thirty-nine participants (25 female 36.8 ± 16.0 yrs and 14 males 29.2 ± 14.2 yrs) volunteered for the study. All participants walked a total of 100 steps at each of three self-selected speeds with a two minute break separating each of the three speed trials. Each gait speed trial was counterbalanced across participants. Pedometers were attached to the waistband of study participants at the level of the anterior superior iliac spine and step lengths were determined according to pedometer manufacturer's recommendations. Study investigators concurrently determined and recorded actual number of steps taken by participants for each of the three speeds. RESULTS The accuracy of the pedometer recordings versus actual steps taken was 81.56 ± 28.81% for self-selected comfortable gait speeds; 92.87 ± 24.85% for fast speeds; and 36.85 ± 39.39 for slow speeds.TableCONCLUSIONS The accuracy of the pedometer used in this study was poor for slow gait speeds while being acceptable at comfortable and faster self-selected speeds. These results suggest that the use of pedometers as a measure of physical activity in individuals with slower than normal gait speeds may prove inaccurate.

Physical Functioning In Patients With Chronic Kidney Disease

Patients with end stage renal disease have markedly reduced levels of physical functioning (PF). Little is known of the levels of PF in patients with chronic kidney disease (CKD) prior to renal replacement therapy or how PF is related to the level of renal function as measured by glomerular filtration rate (GFR). PURPOSE To document levels of PF in patients with chronic renal insufficiency using both objective laboratory measures and performance tests. METHODS Thirty one patients with stage 3 CKD (GFR < 60 ml/min/1.73 m2) (26 males/5 females; mean age 57.1±14.9 yr) were recruited for the study. Testing included symptom limited treadmill testing with measurement of VO, 6 minute walk test (6MW), sit to stand to sit (10 cycles) (STS10), and 20 foot gait speed (GS)(comfortable and fast speed). All measures except for the 6MW were converted to % of age predicted values. RESULTS VO2peak was markedly reduced (x = 17.9±6.77 ml/kg/min) and averaged 59.4±20.2% of age predicted values. Performance measures were not as markedly reduced as a percentage of normal age-predicted values: comfortable GS: 123.7±15.3%; fast GS: 86.0±16.6%; STS10: 60.9±47.3%. The only PF measure that was correlated to GFR was fast GS (r=.37; p.=05). Although the performance tests results were not as reduced compared to age-predicted values as VO2peak there were significant correlations between VO2peak and 6MW (r=.68; p < .001), comfortable GS (r=.413; p.=02) and fast GS (r=.611; p < .001). CONCLUSION Basic functioning of normal gait speed appears to be preserved in patients with CKD, with more impairments noted in activities requiring greater energy expenditure, such as fast gait speed, sit to stand tasks and symptom-limited exercise testing. Exercise training may be warranted in this population with the goal of maintaining overall functioning.

Physical Functioning In Patients With Chronic Kidney Disease

Patients with end stage renal disease have markedly reduced levels of physical functioning (PF). Little is known of the levels of PF in patients with chronic kidney disease (CKD) prior to renal replacement therapy or how PF is related to the level of renal function as measured by glomerular filtration rate (GFR). PURPOSE To document levels of PF in patients with chronic renal insufficiency using both objective laboratory measures and performance tests. METHODS Thirty one patients with stage 3 CKD (GFR < 60 ml/min/1.73 m2) (26 males/5 females; mean age 57.1±14.9 yr) were recruited for the study. Testing included symptom limited treadmill testing with measurement of VO, 6 minute walk test (6MW), sit to stand to sit (10 cycles) (STS10), and 20 foot gait speed (GS)(comfortable and fast speed). All measures except for the 6MW were converted to % of age predicted values. RESULTS VO2peak was markedly reduced (x = 17.9±6.77 ml/kg/min) and averaged 59.4±20.2% of age predicted values. Performance measures were not as markedly reduced as a percentage of normal age-predicted values: comfortable GS: 123.7±15.3%; fast GS: 86.0±16.6%; STS10: 60.9±47.3%. The only PF measure that was correlated to GFR was fast GS (r=.37; p.=05). Although the performance tests results were not as reduced compared to age-predicted values as VO2peak there were significant correlations between VO2peak and 6MW (r=.68; p < .001), comfortable GS (r=.413; p.=02) and fast GS (r=.611; p < .001). CONCLUSION Basic functioning of normal gait speed appears to be preserved in patients with CKD, with more impairments noted in activities requiring greater energy expenditure, such as fast gait speed, sit to stand tasks and symptom-limited exercise testing. Exercise training may be warranted in this population with the goal of maintaining overall functioning.

Effect of age on lower extremity joint moment contributions to gait speed.

We investigated the relationship of hip, knee and ankle function to gait speed in healthy elderly subjects. We hypothesized that the hip extension moment would make a significantly smaller contribution to propulsion power in the elderly than in healthy young subjects even when the elders were ambulating at speeds comparable to those of the young subjects. We analyzed the free speed gait of 16 young and 14 elderly subjects, and the fast gait of the elder subjects. In elderly subjects free speed gait linear power transfer from the leg to the upper body due to the hip and knee moments was decreased compared with young subjects walking at their normal gait speed. However, when asked to walk fast, elders significantly increase knee and hip moment contributions to hip linear power to levels comparable to those of young subjects at a similar speed. These results refute our hypothesis and support our earlier findings indicating that kinematic alterations at the hip are a cause of reduced gait speed in the elderly.

Low-functioning hemodialysis patients improve with exercise training

The Renal Exercise Demonstration Project provided two different approaches to exercise programming to a group of hemodialysis patients. Physical functioning and self-reported health-related quality of life were measured at baseline, after 2 months of independent exercise, and again after 2 months of in-center cycling. This study compares the responses to intervention of patients who initially scored low (<34) on the Physical Component Scale (PCS) on the Medical Outcomes Study Short-Form 36 questionnaire to those who initially scored higher (>34) on the same scale. The high-PCS group scored higher on all physical function tests (normal gait speed, fast gait speed, and sit-to-stand test) at each testing time than the low-PCS group. The high-PCS group improved only on the sit-to-stand test, whereas the low-PCS group improved in all three physical function tests. There were significant differences between the groups in change over time in all the physical scales and the PCS over time, with the low-PCS group showing improvements in response to the intervention and the high-PCS group showing no change over time. No differences in change over time were noted between the groups on the mental scales in either group. We conclude that low-functioning hemodialysis patients can benefit from exercise counseling in both objective measures of physical functioning and self-reported physical functioning. The impact of such interventions seems to be more profound in the lowest functioning patients.

Physical functioning and health-related quality-of-life changes with exercise training in hemodialysis patients

The Renal Exercise Demonstration Project was designed to test the effects of two different approaches to exercise programming on the levels of physical activity, physical functioning, and self-reported health status in hemodialysis patients. Two hundred eighty-six patients were recruited for participation. Intervention patients were given individually prescribed exercise for 8 weeks of independent home exercise, followed by 8 weeks of incenter cycling during dialysis. Physical performance testing was performed at baseline and after each intervention using gait speed, sit-to-stand test, and 6-minute walk. The Medical Outcomes Study Short Form 36-item (SF-36) questionnaire was used to assess self-reported health status. The intervention group showed increased participation in physical activity. There were significant differences between the intervention and nonintervention groups in change over time in normal and fast gait speed, sit-to-stand test scores, and the physical scales on the SF-36, including the physical component scale. The intervention group improved in these test results, whereas the nonintervention group either did not change or declined over the duration of the study. It is clear that improvements in physical functioning result from exercise counseling and encouragement in hemodialysis patients. Because self-reported physical functioning is highly predictive of outcomes in hemodialysis patients, more attention to patients' levels of physical activity is warranted.

Velocity modulation and rhythmic synchronization of gait in Huntington's disease.

This study analyzed the ability of patients with Huntington's disease (HD) to modulate gait velocity without external sensory cues and in response to an auditory rhythmic cue within a frequency entrainment design. Uncued gait patterns of 27 patients were first assessed during normal, slower, and faster self-paced walking. During rhythmic trials, metronome and musical beat patterns were delivered at rates 10% slower and 10-20% faster than baseline cadence to cue gait patterns. After the rhythmic trials, patients were retested at normal gait speed without rhythm. Gait velocities in the patients with HD were below normal reference values in all ranges. Patients were able to significantly (p <0.05) modulate their gait velocity during self-paced and rhythmic metronome cueing but not during music. The ability to modulate gait velocity was retained regardless of the severity of the disease. Gait velocity declined with an increase in disability and chorea score. The disability score differentiated better between gait velocity of moderately and severe patients than chorea score. Slowness of gait was significantly correlated only with disability score and not with chorea. Patients had more difficulty producing adequate step rates than stride lengths during normal and fast walking speeds. After the rhythmic trials, unpaced gait velocity remained significantly (p <0.05) higher than baseline. This carry-over effect was not seen after the uncued trials. Synchronization ability was deficient in all patients, deteriorated with severity of disease, and was already compromised in patients with soft disease signs. Rhythmic tracking of music declined more with severity of disease than metronome tracking. In summary, patients were able to modulate velocity with and without external cues. Velocity adaptations to the external rhythm in music and metronome were achieved without exact synchronization between step cadence and rhythmic stimulus.