Age-dependent variability in spatiotemporal gait parameters and the walk-to-run transition

Adolescents tend to exhibit more variability in their gait patterns than adults, suggesting a lack of gait maturity during this period of ongoing musculoskeletal growth and development. However, there is a lack of consensus over the age at which mature gait patterns are achieved and the factors contributing to gait maturation. Therefore, the purpose of this study was to investigate gait control and maturity in adolescents by determining if differences existed between adolescents and adults in a) the amount of spatiotemporal variability of walking and running patterns across a range of speeds, and b) how swiftly gait patterns are adapted to increasing gait speed during the walk-to-run transition. Forty-six adolescents (10–12-year-olds, n = 17; 13–14-year-olds, n = 12; and 15–17-year-olds, n = 17) and 12 young adults completed an incrementally ramped treadmill test (+0.2 km·h⁻¹ every 30 s) to determine the preferred transition speed (PTS) during a walk-to-run transition. Age-related differences in the variability of stride lengths and stride durations were assessed across 4 speeds (self-selected walking speed, PTS − 0.06 m·s⁻¹, PTS + 0.06 m·s⁻¹, PTS + 0.83 m·s⁻¹). Repeated measures ANOVAs (p < 0.05) compared coefficients of variation for these spatiotemporal parameters, while a one-way ANOVA compared the numbers of gait transitions and speed increments used to identify PTS between the adolescent groups and young adults. Compared to adults, 10–12yo exhibited more spatiotemporal variability during all gait conditions, while 13–17yo only exhibited more variability at PTS + 0.06 m·s⁻¹. No age-dependent pattern was observed in PTS values, but 10–12yo completed more gait transitions over more speed increments than 15–17yo and adults. The development of mature gait patterns is thus a progressive process, with walking maturing at an earlier age than running. As 10-12yo were unable to swiftly adapt gait patterns to the changing task demands, their control mechanisms of gait may not have fully matured yet.     

A foot-pointing task and spatiotemporal gait parameters during walking in sportsmen

Unlike many sports, karate imposes pointing to a target with the lower limb. The nature of each sport could influence gait variables of sportsmen. The aim of this study was to examine the pointing accuracy of limb swing and the spatial and temporal parameters of the walking cycle during walking in karate experts (Group K, n=6) compared to accuracy of nonkarate sportsmen (Group S, n = 11). The second aim of this study was to compare the influence of this skill on the spatial and temporal parameters of the walking cycle between the two groups. The analysis was performed with a device composed of a gait analysis system (locometer) coupled to a lighted walkway. This system provides a measurement of the motor skill and the spatial and temporal gait during walking. Analysis for the pointing task indicated no differences between the Karate and the Sportsmen Groups during walking. Moreover, neither the spatial nor temporal characteristics of walking differed between the two groups. Karate does not therefore seem to develop motor programs specific to enhanced performance on this pointing task during walking or alter the walking cycle as compared to some other competitive sports.     

Ground reaction force and spatiotemporal measurements of the gait of the mouse

Measurement of ground reaction forces with force plates permits quantification of the subtle changes in movement associated with a variety of pathophysiological states. The apparatus used here permits simultaneous recording of other spatial and temporal characteristics of gait. Since the mouse is becoming increasingly important for modeling human disorders, we have recorded ground reaction forces (P) in this species. To date, we have measured the vertical component (P _z ) and found it to be similar to that of other species, in that a greaterP _z is exerted via the forelimb, although the areas under the force/time curves, are not different. Different points of discontinuity are seen in the forelimb and hindlimb curves, indicating differential deployment.P _z varies consistently with stance time and is consistent across the adult life of the mouse. It is suggested that the technique has potential for the study of a variety of mouse models of disease and of their therapies.     

Minimal detectable change of kinematic and spatiotemporal parameters in patients with chronic stroke across three sessions of gait analysis

Three-dimensional gait analysis is the gold standard for gait-assessment in patients with stroke. This technique is commonly used to assess the effect of treatment on gait parameters. In clinical practice, three gait analyses are usually carried out (baseline, after treatment and follow-up), the objectives were to define the reproducibility and the Minimum Detectable Change (MDC) for gait parameters in stance and swing measured using 3D-gait analysis, and to assess changes in MDC across three repeated 3D-gait analyses. Three gait analyses (V1, V2 and V3) were performed at 7-day intervals in twenty-six patients with chronic stroke. Kinematic data (in the sagittal plane, during swing and stance) and spatiotemporal data were evaluated for the paretic limb. Reliability was tested using repeated measures ANOVA with a Tukey post hoc test, and the MDC values were calculated for each parameter. Only the range of hip motion during swing changed significantly between V1 and V2, but no other kinematic parameters changed. No significant differences were observed for the spatiotemporal parameters. MDC values were always higher during the V1vsV2 comparison for both kinematic and spatiotemporal parameters. This is the first study to evaluate the MDC for kinematic and spatiotemporal parameters during stance and swing. Reliability of kinematic and spatiotemporal data across sessions was very good over the three sessions. MDC values were the lowest between V2 and V3 for most parameters. Use of the MDC will allow clinicians to more accurately determine the effect of treatments.     

Validity of visually recorded temporal-distance measures at selected walking velocities for gait analysis

The purpose of this study was to examine the validity of measures of temporal distance in a clinical analysis of gait. Data were collected from 15 normal subjects by one examiner. Equipment consisted of a 10-meter laminated walking track, dictaphone, metronome, and ink markers. The number of errors at four walking speeds were examined using a standardized analysis of gait. Analysis of variance showed a significant number of errors between the first and last halves of the measurement distance and among the four walking velocities. Post hoc analysis using the Scheffé test indicated significant differences in the mean number of errors at the velocities of 60 and 75 versus 25 and 40 m.min-1. An F test for simple effects indicated a significant number of errors occurred during the second half of the measured distance and at walking velocities of 60 and 75 m.min-1. These results indicate that the gait analysis is valid for measurements taken at all of the walking velocities only when recorded over a three-meter distance and only at the velocities of 25 and 40 m.min-1 over a six-meter distance.     

Experiencing nearby locations together in time: the role of spatiotemporal contiguity in children's memory for location

Three studies investigated how experiencing nearby locations together in time influences memory for location. Seven-, 9-, and 11-year-old children and adults learned 20 object locations in a small-scale space. The space was divided into regions by lines or walls. In Study 1, participants learned the locations either region by region or in a random order. Following learning, participants replaced the objects without the aid of the dots marking the locations and the boundaries subdividing the space. They replaced the objects in any order they chose. After experiencing the locations in random orders during learning, only adults underestimated distances between locations belonging to the same group (i.e., region). Conversely, 9- and 11-year-old children and adults who had experienced the locations region by region during learning underestimated these distances. These findings suggest that experiencing nearby locations together in time increases the weight children assign to categorical information in their estimates of location. Results from Studies 2 and 3 in which participants learned the locations region by region and then replaced the objects region by region (Study 2) or in a random order (Study 3) were similar, highlighting the importance of spatiotemporal cues in memory for location. (c) 2002 Elsevier Science (USA).     

Selection of gait parameters during constrained walking

It is commonly thought that at prescribed speeds humans choose gait parameters that minimize the cost of transportation. However, it is unclear whether and how the relationship between step length and step frequency is affected by the additional physiological factors caused by constraints. We performed a series of experiments to understand the selection of gait parameters under different constraints from a probabilistic perspective. First, we show that the effect of constraining step length on step frequency (i.e., monotonically decrease, Experiment I) is different from the effect of constraining step frequency on step length (i.e., inverted-U, Experiment II). Using the results from Experiment I and II, we summarized the marginal distribution of step length and step frequency and built their joint distribution in a probabilistic model. The probabilistic model predicts the selection of gait parameters by achieving the maximum probability of joint distribution of step length and step frequency. In Experiment III, the probabilistic model could well predict gait parameters at prescribed speeds, and it is similar to minimizing the cost of transportation. Finally, we show that the distribution of step length and step frequency were completely different between constrained and non-constrained walking. We argue that constraints in walking are major factors determining how humans choose gait parameters due to their involvement of mediators, i.e., attention or active control. Using the probabilistic model to account for gait parameters has an advantage compared with fixed-parameter models in that it can still include the effect of hidden mechanical, neurophysiological, or psychological variables by grouping them into distribution curves.     

Everyday tasks impair spatiotemporal variables of gait in older adults with Parkinson's disease

IntroductionAlthough it is known that individuals with Parkinson's disease (PD) have difficulties performing dual-task activities, most of the studies have verified the effect of dual tasks on gait using tasks that are uncommon to perform while walking. However, the realization of tasks involving gait that really represents the daily activities carried out by the participants, allow us to detect real fall risk situations of individuals with PD during their gait.ObjectiveOur aim was to verify the influence of daily-life dual-tasks on gait spatiotemporal variables of the older adults with PD.Methods20 older adults without PD and 20 older adults with PD participated in the study. Gait kinematic was analyzed under three different conditions: walking without dual task, walking carrying bags with weight, and walking talking on the cell phone.ResultsOlder adults with PD presented lower speed (p = .001), cadence (p = .039), and shorter step length (p = .028) than older adults without PD during walking without dual tasks. When walking while carrying bags with weight, older adults with PD had a lower speed (p < .001), cadence (p = .015), shorter step length (p = .008), and greater double support time (p = .021) compared with older adults without PD. During walking while talking on the cell phone, older adults with PD walked with lower speed (p < .001), cadence (p = .013), shorter step length (p = .001) and swing time (p = .013), and increased double support time (p = .008) and support time (p = .014) in relation to older adults without PD.ConclusionDaily-life dual tasks impair the spatiotemporal variables of gait in the older adults with PD, which was most evident during walking talking on the cell phone.     

The role of the physical context in supporting young children's use of spatiotemporal organization in recall

Four experiments were conducted to investigate the role of the physical context in supporting 3‐ to 5‐year‐olds' use of spatiotemporal organization in recall. Children were familiarized with several target items and their corresponding landmarks arranged along a path in a model park. After familiarization, an experimenter removed the target items from the park. In Experiment 1, 3‐ and 4‐year‐olds recalled the missing items with the park either in view or out of view. When the park model was in view, 4‐ year‐olds used the order of the items along the path to structure their recall. In Experiment 2, 4‐ and 5‐year‐olds recalled the missing items with the landmarks arranged either in the same order as in familiarization or in a new order. Children used the order of landmarks along the path at test to structure their recall, even though the order of landmarks changed from familiarization to test. Experiment 3 was identical to Experiment 2, except that the path was removed from the park. Five‐year‐olds used the order of landmarks along the path at test to structure their recall when the order of landmarks remained the same from familiarization to test, but had much more difficulty doing so when the order of landmarks changed from familiarization to test. Using a more difficult task, Experiment 4 revealed that spatiotemporal organization was positively related to amount recalled. Together, these findings suggest that the structure of the physical environment plays an important role in supporting young children's use of spatiotemporal organization in recall.     

The Effect of Method Characteristics on Retest Score Gains and Criterion-Related Validity

Purpose

We sought to empirically assess the effect of predictor method characteristics (test form, item-type, and test-type) on retest score change associated with an invariant construct—general mental ability (GMA)—and to evaluate the effect of retesting on the criterion-related validity of assessments that vary in their susceptibility to retest effects.

Design

Three hundred seven individuals completed a battery of GMA assessments. After a 6-week interval, participants returned to the testing site to retest using both alternate and identical forms of the initial assessments.

Findings

Greater score gains were observed on assessments comprising heterogeneous item-types than homogeneous item-types, and on performance-based assessments than self-report assessments. However, despite variations in score gains, the relationships between the initial test scores and criterion scores were no different than the relationships between retest scores and criterion scores for all assessments.

Implications

Tests and procedures that reduce reliance on test- or item-specific knowledge and skill may help minimize score changes due to retesting across multiple administrations. Moreover, under the boundary conditions present in this study, the criterion-related validity of ability assessments may not be affected by increases in test-specific knowledge and skills.

Originality/Value

Despite the prevalence and industry support of retesting, a comprehensive understanding of retest score change still eludes researchers and practitioners. This ambiguity may be due in part to neglecting the method-construct distinctions in the retest literature. This is the first report to explicitly utilize the method-construct distinction in an effort to examine the causes and consequences of retest effects.

     

Use of the gait deviation index for the evaluation of patients with Parkinson's disease

The authors aimed to determine whether the Gait Deviation Index (GDI) could be feasible to characterize gait in patients with Parkinson's disease (PD) and evaluate outcomes of levodopa treatment. Twenty-two PD participants were evaluated with clinical examination and 3-D quantitative gait analysis (GDI was calculated from gait analysis) in 2 states (OFF and ON) after taking levodopa. Twenty age-matched healthy participants (CG) were included as controls. The GDI value in the OFF state was 83.4 ± 11.5 (statistically different from CG) while clinical scales demonstrated a moderate-severe gait impairment of these patients. Significant improvements are evident from clinical scores and by GDI values in the ON state. The mean GDI for the ON state (GDI(ON): 87.9 ± 10.4) was significantly higher than in for the OFF state (GDI(OFF): 83.4 ± 11.5), indicating a global gait improvement after the treatment. The results show that GDI has lower value as an indicator of pathology in PD patients than in quantifying the effects of levodopa treatment in PD state.     

A Validity and Multiple Regression Study of Performance in the GEPI as a Predictor for Performance on the GED

This study attempts to determine the relationship between the subtests of the General Education Performance Index (GEPI) and the revised version of the General Educational Development Test (GED), and reports a technique whereby performance on the GEPI may be used to predict performance on the GED. Participants were men and women, aged 16 to 62, who were given the GEPI and then the GED. Multiple regression equations were generated to predict GED scores using age and each GEPI score. No significant correlation was found between age and GED scores or between age and GEPI scores, but a highly significant correlation (p > .001) was found between each GEPI subtest score and the subsequent score attained on the GED. Regression equations for each subtest and cross validation that demonstrated high predictive validity for each regression equation are reported.     

Kinematic gait parameters for older adults with Parkinson's disease during street crossing simulation

Safe street crossing is important for older adults' social inclusion. We assessed gait kinematic adaptation under different simulated street crossing conditions in older adults with Parkinson's disease (PD) and made comparisons with older adults without PD to understand how PD interferes in outdoor task performance, helping in the development of strategies to reduce road traffic accident risk. In 20 older adults without PD (control group – CG) and 20 with PD (GPD), we assessed usual gait (C1), gait during street crossing simulation (C2), and gait during reduced-time street crossing simulation (C3). Velocity, step length, and step, swing, stance, and double support time were analyzed. Spatiotemporal differences in gait between groups and conditions were analyzed. The GPD walked 16% slower in C1 and 12% slower in C2 and C3 than the CG. GPD also took 11% shorter steps in C1 and 9.5% shorter steps in C2. The double support time was 8.5% greater in C1. In intragroup comparisons, there were significant differences in all gait conditions. The CG showed increased velocity (C2 15% > C1; C3 13% > C2; C3 26% > C1), step length (C2 8% > C1; C3 5% > C2; C3 13% > C1), and swing time (C2 2% > C1; C3 3.7% > C2; C3 6% > C1), and decreased step time (C2 7.5% < C1; C3 8% < C2; C3 15% < C1), stance time (C2 1.3% < C1; C3 2.5% < C2; C3 3.6% < C1), and double support time (C2 6.3% < C1; C3 10.5% < C2; C3 16% < C1). GPD showed increased velocity (C2 19% > C1; C3 13.5% > C2; C3 29.7% > C1), step length, (C2 6% > C1; C3 7% > C2; C3 16% > C1), and swing time (C2 3% > C1; C3 3% > C2; C3 5.5% > C1) and decreased step time (C2 10.3% < C1; C3 7.7% < C2; C3 17% < C1), stance time (C2 1.7% < C1; C3 1.7% < C2; C3 3.4% < C1), and double support time (C2 7% < C1; C3 9.5% < C2; C3 16% < C1). Kinematic changes observed in the intergroup comparison show that participants with PD had lower velocity in all conditions. However, per the intragroup results, both participants with and without PD managed to significantly modify gait variables to attempt to cross the street in the given time. It is necessary to assess whether this increases fall risk by exposing them to road traffic accidents.     

More than g: Evidence for the Incremental Validity of Performance-Based Assessments for Predicting Training Performance

Past research has consistently shown that tests measuring specific cognitive abilities provide little if any incremental validity over tests of general mental ability when predicting performance on the job. In this study, we suggest that the seeming lack of incremental validity may have been due to the type of content that has traditionally been assessed. Therefore, we hypothesised that incremental validity can be obtained using specific cognitive abilities that are less highly correlated with g and are matched to the tasks performed on the job. To test this, we examined a recently developed performance-based measure that assesses a number of cognitive abilities related to training performance. In a sample of 310 US Navy student pilots, results indicated that performance-based scores added sizeable incremental validity to a measure of g. The significant increases in R² ranged from .08 to .10 across criteria. Similar results were obtained after correcting correlations for range restriction, though the magnitude of incremental validity was slightly smaller (ΔR² ranged from .05 to .07).     

The Construct Validity of Assessment Centre Performance Dimensions

Evidence regarding the construct validity of assessment centre performance dimensions is reviewed. The evidence strongly suggests that variance in ratings tends to reflect exercises more than individual performance dimensions, thus calling into question the construct validity and utility of these dimensions. A number of biases in the assessment centre process, as well as more general rating biases are noted that may be responsible for these pervasive exercise effects. Suggestions are made for enhancing the construct validity of performance dimensions.     

Reliability of gait parameters in children under two years of age

The walking movement of children of school age and adults can be regarded as very consistent. However, few studies have reported reliability of gait parameters in very young children that may be used as normative data for the clinical assessment of gait. In the present study, nine normal children of ages 10 to 21 mo. were assessed cross-sectionally using three-dimensional video analysis and digitization to assess within-day reliability of gait kinematics. Between-subject differences in gait kinematics were also examined. In addition, one child was assessed at the onset of independent walking and at monthly intervals thereafter to assess changes in gait kinematics during the first 8 mo. of autonomous walking. The case study allowed the acquisition of pilot data for longitudinal studies of this age group. 10 kinematics variables regarded as indicators of efficient walking were measured, and reliability was assessed using one-way analysis of variance and coefficient of variation. The study showed that all children produced reliable within-day results; however, the gait of each child was unique. In the case study, the between-month differences in gait kinematics were significant. The findings may be of clinical interest for pediatricians and child neurologists given the lack of normative data for this age group.     

Incremental Validity of Situational Judgment Tests for Task and Contextual Job Performance

This paper has three goals. First, it responds to calls for additional research on subgroup differences in situational judgment tests. Second, it expands the cumulative knowledge on the incremental validity of situational judgment tests beyond cognitive ability and personality. Third, it examines the validity and incremental validity of various predictors for both task and contextual performance.