Walking In Healthy Young Adults Research Articles

Recovering whole-body angular momentum and margin of stability after treadmill-induced perturbations during sloped walking in healthy young adults

Although humans are well-adapted to negotiating sloped terrain, balance recovery after a disturbance on slopes is poorly understood. This study investigated how slope affects recovery from unanticipated simulated trips and slips. Eighteen healthy young adults walked on a split-belt treadmill at 1.25 m/s and three slope angles (downhill: − 8°; level: 0°; uphill: + 8°), with slip- and trip-like perturbations applied randomly at heel-strike. We evaluated balance recovery using whole-body angular momentum (WBAM) and perturbation response (PR), for which larger PR values indicate greater deviation of the margin of stability from baseline, therefore, greater destabilisation after perturbation. Overall, trips were more destabilising than slips, producing larger PR and greater range and integral of WBAM across all tested slopes, most significantly in the sagittal plane. Contrary to expectation, sagittal-plane PR post-trip was greatest for level walking and smallest for downhill walking. Heightened vigilance during downhill walking may explain this finding. Recovery strategy in both frontal and sagittal planes was consistent across all slopes and perturbation types, characterized by a wider and shorter first recovery step, with trips requiring the greatest step adjustment. Our findings advance understanding of the robustness of human locomotion and may offer insights into fall prevention interventions.

The influence of step width on balance control and response strategies during perturbed walking in healthy young adults

Individuals with neuromuscular deficits often walk with wider step widths compared to healthy adults. Wider steps have been linked to a higher destabilizing frontal-plane external moment and greater range of frontal-plane whole-body angular momentum (HR), which is an indicator of decreased balance control. The purpose of this study was to experimentally determine 1) how step width alters balance control during steady-state walking, and 2) if step width changes the balance response strategies following mediolateral surface perturbations in healthy adults.Fifteen healthy young adults (7 male, age: 25 ± 4 years) walked on an instrumented treadmill at narrow, self-selected, wide and extra-wide step widths. During perturbed trials, the treadmill provided random mediolateral surface translations to each foot midway through single-leg-stance. Muscle electromyography, biomechanical measures (HR, frontal-plane external moment and joint moments) and deviations (differences in these measures between the perturbed and unperturbed walking trials) were compared across step widths.During steady state walking, wider steps were associated with decreased balance control. Increasing step widths were also associated with increased gluteus medius activity and reduced hip abduction and ankle inversion moments, which suggests healthy subjects rely more on a lateral ankle strategy to maintain balance at increasing step widths. There was no change in the plantarflexion moment. During perturbed walking, lateral, but not medial, surface translations adversely affected balance control. Further, wider steps did not change the balance response strategies following the perturbations, which suggests healthy individuals have the capacity to respond similarly to the perturbations at different step widths.

The influence of altered foot placement and cognitive load on balance control during walking in healthy young adults

BackgroundClinical populations often walk with altered foot placement, which can adversely affect balance control. However, it is unknown how balance control during walking is influenced when combining a cognitive load with altered foot placement. Research QuestionIs balance control during walking adversely affected by the combination of a more complex motor task, such as walking with altered foot placements, with a cognitive load? MethodsFifteen young healthy adults walked on a treadmill with and without a spelling cognitive load during normal walking, with step width targets (self-selected width, narrow, wide and extra wide), or with step length targets (self-selected length, short and long). ResultsCognitive performance, measured by correct spelling response rate, decreased from self-selected (2.407 ± 0.6 letters/s) to the extra wide width (2.011 ± 0.5 letters/s). The addition of the cognitive load caused a decrease in frontal plane balance control across all step lengths (15% change) and at the wider step widths (16% change), but only caused a slight decrease in the sagittal plane for the short step length (6.8% change). SignificanceThese results suggest that when combining a cognitive load with walking at non-self-selected widths, a threshold exists at wider steps where attentional resources become insufficient and balance control and cognitive performance decrease. Because decreased balance control increases the risk of falling, these results have implications for clinical populations who often walk with wider steps. Furthermore, the lack of changes to sagittal plane balance during altered step length dual-tasks further supports that frontal plane balance requires more active control.

The effects of the tension of figure-8 straps of a soft ankle orthosis on the ankle joint kinematics while walking in healthy young adults: A pilot study

BackgroundFigure-8 straps are commonly used in ankle orthoses, which are provided to reduce the risks of primary and recurrent sprain by providing functional support. Functional treatment with ankle orthoses can provide better rehabilitation than immobilization for a mild ankle sprain. However, it is not known how much tension should be applied to the straps while donning the orthosis to optimize its effectiveness. Research questionThe aim of this study was to investigate the effects of figure-8 strap tension of a soft ankle orthosis on ankle joint kinematics in the sagittal, coronal, and transverse planes during gait in healthy young adults. MethodsTen healthy adults (five males and five females) were enrolled in this study. The 3-dimensional motion analysis system was used to evaluate the ankle kinematics of the participants during gait under five conditions: no soft ankle orthosis, soft ankle orthosis with no figure-8 straps tension (lace-up only), 50 N, 80 N, and 110 N tension of the figure-8 straps, respectively. All participants walked in a straight path at a comfortable speed. ResultsPlantarflexion angles were significantly reduced with 110 N of tension in the figure-8 straps when compared to the lace-up only and a moderate correlation with r = 0.34 (p = 0.03) was observed between the tensions of figure-8 straps and maximum plantarflexion angles at pre-swing of a gait cycle. No significant effects on ankle joint angles were demonstrated in the coronal and transverse planes. SignificanceThis study showed that increasing the tension of the figure-8 straps could restrict the ankle joint plantarflexion angle during pre-swing in gait. However, it might not affect inversion/eversion or internal/external rotation angles of the ankle joint in individuals without ankle pathologies.

Effects of obesity and foot arch height on gait mechanics: A cross-sectional study.

Foot arch structure contributes to lower-limb joint mechanics and gait in adults with obesity. However, it is not well-known if excessive weight and arch height together affect gait mechanics compared to the effects of excessive weight and arch height alone. The purpose of this study was to determine the influences of arch height and obesity on gait mechanics in adults. In this study, 1) dynamic plantar pressure, 2) spatiotemporal gait parameters, 3) foot progression angle, and 4) ankle and knee joint angles and moments were collected in adults with normal weight with normal arch heights (n = 11), normal weight with lower arch heights (n = 10), obesity with normal arch heights (n = 8), and obesity with lower arch heights (n = 18) as they walked at their preferred speed and at a pedestrian standard walking speed, 1.25 m/s. Digital foot pressure data were used to compute a measure of arch height, the Chippaux-Smirak Index (CSI). Our results revealed that BMI and arch height were each associated with particular measures of ankle and knee joint mechanics during walking in healthy young adults: (i) a higher BMI with greater peak internal ankle plantar-flexion moment and (ii) a lower arch height with greater peak internal ankle eversion and abduction moments and peak internal knee abduction moment (i.e., external knee adduction moment). Our results have implications for understanding the role of arch height in reducing musculoskeletal injury risks, improving gait, and increasing physical activity for people living with obesity.

The immediate effect of foot orthoses on gluteal and lower limb muscle activity during overground walking in healthy young adults.

Although foot orthoses are often used in the management of lower limb musculoskeletal conditions, their effects on muscle activation is unclear, especially in more proximal segments of the lower limb. Primary aim: Is there an immediate effect of foot orthoses on gluteal muscle activity during overground walking in healthy young adults? Secondary aim: Is there an immediate effect of foot orthoses on the activity of hamstring, quadriceps and calf muscles? In eighteen healthy young adults, muscle activity was recorded using fine wire electrodes for gluteus minimus (GMin; anterior, posterior) and gluteus medius (GMed; anterior, middle, posterior); and surface electrodes for gluteus maximus (GMax), hamstring, quadriceps and calf muscles. Participants completed six walking trials for two conditions; shoe and shoe with prefabricated foot orthoses. Muscle activity was normalised to the peak activity of the shoe condition and analysed using one-dimensional statistical non-parametric mapping to identify differences across the gait cycle. Activity of GMed (anterior, middle, posterior) and GMin (posterior) was reduced in early stance phase when the orthosis was worn in the shoe (p < 0.05). GMin (anterior) activity was significantly reduced during swing (p < 0.05). Muscle activity was also significantly reduced during the orthoses condition for the lateral hamstrings and calf muscles (p < 0.05). Using foot orthoses may provide a strategy to reduce demand on GMin, GMed, lateral hamstring and calf muscles while walking.

Temporary Unilateral Caloric Vestibular Stimulation Affects Balance and Gait Control During Walking in Healthy Young Adults.

Objective: This study aimed to examine the individual differences and factors affecting balance and gait control during walking (i.e., dynamic equilibrium) in healthy young adults subjected to unilateral caloric vestibular stimulation (CVS).Methods:Sixty-six participants completed questionnaires related to motion sickness. All participants were subjected to the head-up tilt test (HUT), which assesses orthostatic dysregulation, followed by inner ear stimulation with cold water (20°C) for 60 s. Subsequently, all participants performed a 6 m walking test with their eyes open.Results: CVS resulted in horizontal nystagmus. The measured distance of sway from the centerline on the goal line ranged from 0 to 600 cm. Both motion sickness and orthostatic dysregulation (OD) were associated with the distance of sway from the centerline.Conclusions: Autonomic dysfunction affects the dynamic equilibrium and might cause individual gait differences. Further study is warranted to quantify the autonomic function and clarify individual variations in dynamic equilibrium, after unilateral CVS.

Test–Retest Reliability and the Effects of Walking Speed on Stride Time Variability During Continuous, Overground Walking in Healthy Young Adults

Studies have investigated the reliability and effect of walking speed on stride time variability during walking trials performed on a treadmill. The objective of this study was to investigate the reliability of stride time variability and the effect of walking speed on stride time variability, during continuous, overground walking in healthy young adults. Participants completed: (1)2 walking trials at their preferred walking speed on 1day and another trial 2 to 4 days later and (2)1 trial at their preferred walking speed, 1 trial approximately 20% to 25% faster than their preferred walking speed, and 1 trial approximately 20% to 25% slower than their preferred walking speed on a separate day. Data from a waist-mounted accelerometer were used to determine the consecutive stride times for each trial. The reliability of stride time variability outcomes was generally poor (intraclass correlations: .167-.487). Although some significant differences in stride time variability were found between the preferred walking speed, fast, and slow trials, individual between-trial differences were generally below the estimated minimum difference considered to be a real difference. The development of a protocol to improve the reliability of stride time variability outcomes during continuous, overground walking would be beneficial to improve their application in research and clinical settings.

Negative effects of blood flow restriction on perceptual responses to walking in healthy young adults: A pilot study

BackgroundBlood flow restriction (BFR) exercise is recognized as a beneficial strategy in increasing skeletal muscle mass and strength. These positive effects can also be obtained by a mild exercise mode such as walking. However, BFR exacerbates some perceptual responses, such as perceived exertion response, induced by exercise. Despite this knowledge, the negative effects of BFR exercise on major perceptual parameters related to exercise adherence remain unknown. Furthermore, compared with other exercise modes (e.g., resistance exercise), little is known regarding the effects of BFR on perceptual responses to walking. To clarify these issues, we examined the effects of BFR walking on perceptual parameters, including exercise adherence-related parameters. MethodsEighteen healthy, young males performed both BFR and non-BFR (NBFR) walking on a treadmill in a crossover design. Exercise was performed as five sets of 2-min walking with 1-min rest intervals. BFR walking was performed with 200 mmHg pressure cuffs placed around the proximal region of the thighs. NBFR walking was performed without pressure cuffs. ResultsRatings of perceived exertion and leg discomfort were significantly higher during BFR walking than during NBFR walking. Affect and task motivation were significantly lower during BFR walking than during NBFR walking; by contrast, perceived pain was significantly higher during BFR walking than during NBFR walking. Enjoyment immediately after walking was significantly lower with BFR than with NBFR. ConclusionsThese findings suggest that BFR walking induces greater responses of perceptual parameters, including exercise adherence-related parameters, than does NBFR walking. Therefore, BFR walking may decrease adherence to this exercise. To further popularize BFR exercise, further studies are needed to develop effective strategies to minimize the BFR-induced negative effects on perceptual responses.

Compensation of stochastic time-continuous perturbations during walking in healthy young adults: An analysis of the structure of gait variability

BackgroundDuring everyday locomotion, we cope with various internal or external perturbations (e.g. uneven surface). Uncertainty exists on how unpredictable external perturbations increase noise within the motor system and if they are compensated by employing covariation of the limb joints or rather due to decreased sensitivity of an altered posture. Research questionDo continuous stochastic perturbations affect the structure of gait variability in young and healthy adults? MethodsIn a cross-over study, gait kinematics of 21 healthy young sports students were registered during treadmill walking with and without continuous stochastic perturbations. Using the TNC method, the following aspects were analyzed: (a) the sensitivity of body posture to perturbations (‘tolerance’) decreasing gait variability, (b) the unstructured motor ‘noise’ increasing gait variability and (c) the amount of ‘covariation’ of the limb joints. ResultsCompared to normal walking, gait variability was significantly increased (p < .001) during walking with perturbations. The negative effect of noise was partly compensated by improved ‘covariation’ of leg joints (p < .001). The aspect ‘tolerance’ had a small effect on increasing gait variability during stance phase (p < .001) and decreasing gait variability during swing phase (p < .001). SignificanceIncreased motor noise due to external perturbations is partly compensated by improved covariation of the limb joints. However, the effect of an altered posture slightly affects gait variability. Further studies should focus on different populations (e.g. older participants) to see if they use the same mechanism (improved covariation) to compensate for stochastic perturbations.

Assessment of diurnal variation of stride time variability during continuous, overground walking in healthy young adults

Background: There is emerging evidence that gait variability outcomes provide unique insights regarding the status of an individual’s locomotor control system; however, there is currently limited evidence on the within-day reliability of stride time variability (STV) outcomes, or whether they demonstrate diurnal variation, when measured during continuous, overground walking in healthy young adults. Research Questions: 1) Are STV outcomes measured in the morning and afternoon during continuous, overground walking significantly different in healthy young adults? 2) What is the within-day reliability of STV outcomes measured during continuous, overground walking in healthy young adults?. Methods: Thirty-one healthy young adults (20.8 ± 3.7 years) completed two 10-minute continuous, overground walking trials on the same day (9:00-11:00am and 3:00-5:00pm) at their preferred walking speed. Data from a waist-mounted tri-axial accelerometer were used to determine the series of consecutive stride times for each trial. Results: There were no significant differences between sessions for average walking speed, average stride time, or STV. The within-day reliability was excellent for average walking speed and stride time, and generally poor to fair for STV. Significance: Healthy young adults do not appear to demonstrate diurnal variation in STV outcomes during continuous, overground walking; however, the development of a protocol to improve their reliability, as well as the establishment of normative ranges for such outcomes, would be beneficial to improve their application and interpretation in research and clinical settings.

Less noise during dual-task walking in healthy young adults: an analysis of different gait variability components.

Dual-task costs of gait (variability) parameters are frequently used to probe the grade of automaticity of walking. However, recent studies reported contradicting dual-task costs for different gait variability measures within the same cohorts. The effects of a dual-task on the gait pattern are, thus, not fully understood. The aim of the current study was to analyze the different gait variability components ('Tolerance', 'Noise', and 'Covariation') during dual-task walking compared to single-task walking. In an experimental study, 21 young and healthy adults (11 males, 10 females, age: 24 ± 3years) were included. The participants completed three experimental conditions: (a) single-task walking, (b) dual-task walking (serial-seven subtractions), and (c) cognitive single task in sitting position. To analyze different gait variability components, we applied a method which distinguishes the three components: 'Tolerance', 'Noise', and 'Covariation' (TNC). To test for differences, we used the statistical parametric mapping method. Compared to single-task walking, the results depict lower gait variability of the result parameters during the dual-task condition at 0-15% (p = 0.010) and 94-100% (p = 0.040) of the stance phase and 0-63% (p < 0.001) during the swing phase. The decreased result parameter variability was due to less (sensorimotor) 'Noise' (stance: 2-100%, p < 0.001; swing: 2-59%, p < 0.001) during the dual-task walking condition. In further studies, the sources of the reduced unstructured (sensorimotor) noise in the dual-task condition should be analyzed to better understand the effect of a cognitive dual task on the gait pattern.

Differences In Indoor, Outdoor, And Treadmill Walking In Healthy Young Adults

The ability to ambulate within one’s environment is an important skill for everyday life, however, traditional methods of assessing gait involve walking in controlled settings that may not represent performance in real-world environments. Laboratory and clinically-based quantitative gait assessments are often conducted in a sterile and uniform environment and treadmill walking assessments, used to collect a large amount of walking data, are conducted with an externally driven speed and fixed environment. As such, gait demonstrated in these assessments may not reflect gait performance in the real-world environment. PURPOSE: To compare gait behavior among overground indoor, outdoor, and treadmill walking in healthy adults. METHODS: 16 healthy young adults (5M, 11F, 21±2yrs) performed three walking trials (500m each) at a self-selected pace: indoors around a gymnasium (IN), outdoors along a sidewalk (OUT), and on a treadmill (TM). Data were collected using wearable sensors and the following variables were calculated for each trial: cadence, gait velocity, double support %, step time, stride length. Two repeated-measures MANOVAs were used to compare mean values and variability (standard deviation (SD)) across conditions. RESULTS: Significant differences were found across the conditions for both mean values (Λ*=.038, F(10,6)= 15.18, p=.002), and variability (Λ*=.037, F(10,6)= 15.41, p=.002). Univariate tests showed differences in mean values between all three conditions for cadence, gait velocity, step time, and stride length (p<.003), and greater double support time in the TM condition than the IN or OUT conditions (p=.006). Univariate tests for variability measures failed to detect statistically significant differences (p>.01). The TM condition had a lower gait velocity SD than IN or OUT (p=.001). CONCLUSION: Healthy young adults adopt different walking strategies while walking indoors, outdoors, and on a treadmill.

Cognitive control processes associated with successful gait performance in dual-task walking in healthy young adults.

Growing evidence suggests that the reliance on cognitive control processes during normal walking increases as the locomotor task gets more complex and challenging. The aims of the present study were to explore the (negative) effects of smartphone gaming on gait performance in healthy young adults, and to identify cognitive resources that might help to maintain high gait performance during dual-task walking. Gait speed and gait variability during walking at a self-selected comfortable speed were assessed in 40 healthy, young adults, and compared between single-task and dual-task walking (i.e., concurrent smartphone gaming) in undisturbed, simple and more challenging walking environments (i.e., stepping over an obstacle while walking). Based on single-task performance, dual-tasking costs were computed and linked to higher-level cognitive control processes, which were assessed for each individual. Cognitive function testing encompassed tests on the mental representation of the gait, working memory capacity, inhibitory control and cognitive flexibility. Our data revealed that gaming on a smartphone while walking strongly affected participants' gait performance (i.e., up to 26.8% lower gait speed and 60.2% higher gait variability), and decrements in gait performance were related to higher cognitive control processes. Cognitive resources that were associated with performance decrements in dual-task walking include response inhibition, cognitive flexibility, working memory, and a well-structured mental representation of the gait. From that, it appears that even in healthy young adults better cognitive resources may help to maintain high gait performance in situations, in which we have to deal with dual- or multi-task demands (e.g., using a smartphone) while walking.

Visual scanning behavior during distracted walking in healthy young adults

BackgroundAn epidemic of pedestrian accidents when walking while texting suggests that people are less aware of their surroundings during distracted walking, and highlights the importance of visual scanning for pedestrian safety. Quantitative examination of visual scanning during distracted walking is still lacking. Research questionIs visual scanning behavior altered by distracted walking in healthy young adults? MethodsWe compared visual scanning behavior in 20 young adults during usual (single-task) walking, walking while performing a letter-fluency task, and walking while texting. Visual scanning behavior was measured by fixation count and dwell time percentage in specific areas of interest. Dual-task effects on gait speed, letter fluency, texting speed and accuracy, and situational awareness were also examined. ResultVisual scanning behavior differed between the three walking conditions. During dual-task letter fluency, participants had significantly more non-walking path fixations than either of the other two conditions (i.e., more frequent, broader visual scanning). Conversely, during dual-task texting, gaze was focused predominantly on the phone, with little visual scanning of the walking path and surrounding environment. When walking without texting or talking, gaze was directed equally to far walking path and surrounding environment. SignificanceTexting while walking is associated with a considerable reduction in overt visual attention to the walking path and surrounding areas. Whether this translates to reduced conscious awareness of environmental stimuli remains unclear. Performing a verbal task while walking was associated with more frequent, wider visual scanning behavior, which may be specific to the nature of the verbal task in this study.

The effect of light touch on balance control during overground walking in healthy young adults

Balance control is essential for safe walking. Adding haptic input through light touch may improve walking balance; however, evidence is limited. This research investigated the effect of added haptic input through light touch in healthy young adults during challenging walking conditions. Sixteen individuals walked normally, in tandem, and on a compliant, low-lying balance beam with and without light touch on a railing. Three-dimensional kinematic data were captured to compute stride velocity (m/s), relative time spent in double support (%DS), a medial-lateral margin of stability (MOSML) and its variance (MOSMLCV), as well as a symmetry index (SI) for the MOSML. Muscle activity was evaluated by integrating electromyography signals for the soleus, tibialis anterior, and gluteus medius muscles bilaterally. Adding haptic input decreased stride velocity, increased the %DS, had no effect on the MOSML magnitude, decreased the MOSMLCV, had no effect on the SI, and increased activity of most muscles examined during normal walking. During tandem walking, stride velocity and the MOSMLCV decreased, while %DS, MOSML magnitude, SI, and muscle activity did not change with light touch. When walking on a low-lying, compliant balance beam, light touch had no effect on walking velocity, MOSML magnitude, or muscle activity; however, the %DS increased and the MOSMLCV and SI decreased when lightly touching a railing while walking on the balance beam. The decreases in the MOSMLCV with light touch across all walking conditions suggest that adding haptic input through light touch on a railing may improve balance control during walking through reduced variability.

The influence of cognitive load on metabolic cost of transport during overground walking in healthy, young adults.

Our aim was to examine whether cognitive processing during walking increases the metabolic cost of transport in healthy young adults. Twenty healthy, young adults completed five conditions: (1) walking at a self-selected speed (spontaneous single-task), (2) seated resting (baseline), (3) performing cognitive task while seated (cognitive single-task), (4) walking while simultaneously performing the cognitive task (dual-task), and (5) single-task walking at a speed that matched the participant's dual-task gait speed (matched single-task). Rate of oxygen consumption (V̇O2) was recorded during all conditions. Gait speed and cost of walking (Cw; oxygen consumed per distance traveled) were recorded during all walking conditions. Reaction time and accuracy of responses in the cognitive task were recorded during all cognitive task conditions. Data from the fifth minute of each 5-min condition were analyzed. There was no difference in V̇O2 between the dual-task and matched single-task walking conditions. V̇O2 in the seated cognitive condition was significantly smaller than both walking conditions, but was not significantly different than zero. Cw was significantly greater during the matched single-task walking condition than during the dual-task walking condition. However, the difference in Cw was so small that it is unlikely to be clinically significant (0.008mLO2/kg/m, 95% CI 0.002-0.014). Cognitive processing while walking may not increase energy demands of walking in healthy young adults. Maintaining non-preferred gait speed (matched speed) overground continuously for 5min may require attentional resources, and thereby increase metabolic costs relative to walking at habitual speed.

Comparison of accelerometer-based and treadmill-based analysis systems for measuring gait parameters in healthy adults.

[Purpose] This study aimed to determine the correlation between accelerometer-based and treadmill-based analysis systems for measuring gait parameters during comfortable walking in healthy young adults. [Subjects and Methods] Twenty-three healthy adults participated in this study. Gait parameters were measured with simultaneous use of accelerometer-based and treadmill-based gait analysis systems, while participants walked for 30 s. [Results] There was a highly-significant correlation between the two systems with respect to cadence and velocity. The cadence, speed, and stride measured with the accelerometer system were significantly and highly correlated with the cadence, velocity, and number of steps measured with the treadmill-based system. The gait cycle duration measured with the accelerometer system was significantly and highly correlated with the step time and stride time measured with the treadmill-based gait system. [Conclusion] Gait analysis using an accelerometer system is a valid method for assessment of the effectiveness of therapeutic interventions in a clinical setting.

Efficacy of a trunk orthosis with joints providing resistive force on low back load during level walking in elderly persons.

PurposeThe effects of lumbosacral and spinal orthoses on low back pain and gait are not exactly clear. We previously developed a trunk orthosis with joints providing resistive force on low back load to decrease such load, and confirmed its positive effects during level walking in healthy young adults. Therefore, we aimed to determine the efficacy of this trunk orthosis during level walking in healthy elderly subjects.MethodsFifteen community-dwelling elderly subjects performed level walking at a self-selected speed without an orthosis, with our orthosis, and with a lumbosacral orthosis. Kinematic and kinetic data were recorded using a three-dimensional motion analysis system, and erector spinae activity was recorded by electromyography.ResultsWhen comparing the three conditions, our orthosis showed the following effects: it decreased the peak extension moment, increased the peak flexion moment, decreased the lateral bending angle, increased the peak thoracic extension angle, and had significantly lower erector spinae activity and significantly larger peak pelvic forward tilt angles.ConclusionOur orthosis with joints providing resistive force decreased low back load and modified trunk and pelvis alignments during level walking in healthy elderly people.

Reduction in Energy Expenditure During Walking Using an Automated Stride Assistance Device in Healthy Young Adults

ObjectiveTo investigate the effects of an automated stride assistance device that assists hip joint flexion and extension movement in energy expenditure during walking in healthy young adults using an expired gas method. DesignProspective, single-group design to compare the differences of energy expenditure between 2 assistive conditions. SettingLaboratory. ParticipantsHealthy volunteers (N=10) aged 21 to 32 years. InterventionsNot applicable. Main Outcome MeasuresOxygen consumption per unit time (V˙o2) cost (ml·kg−1·m−1), and heart rate (beats/min) were measured in 2 assistive conditions (with 3-Nm hip motion assistance and without assistance) and at 2 walking speeds (comfortable walking speed [CWS] and maximum walking speed [MWS]). ResultsThere were no significant differences in walking speed between the with- and without-assistance conditions at either the CWS or MWS. The V˙o2 cost and heart rate were significantly reduced in the with-assistance condition compared with the without-assistance condition, at both the CWS and MWS. The reduction in the V˙o2 cost during the with-assistance condition, relative to the without-assistance condition, was 7.06% at the CWS and 10.52% at the MWS. ConclusionsThe automated stride assistance device is useful for reducing energy expenditure during walking in healthy adults. Further studies are warranted to investigate if this device provides substantial help to individuals with impaired mobility as a result of strength deficits.