A comparison of gait characteristics in young and old subjects

"Fall Risk Scoring" in Outpatient Gait Analysis: Validation of a New Fall Risk Assessment for Nursing Home Residents

Falls in senior home residents are common. Individual preventive training can lower the fall risk. To detect the need for training, a systematic assessment of the individual fall risk is needed. The aim of this study was thus to assess whether a fall risk score based on free field insole measurements can distinguish between an at-risk group of senior home residents and a healthy young control group. A published fall risk score was used in senior home residents over the age of 75 and a young (< 40 years) control group to determine the individual fall risk. In addition, the fall events over 12 months were assessed. Statistical analysis including ROC analysis was performed to determine the ability of the score to detect participants at heightened fall risk. In total, 18 nursing home residents and 9 young control participants were included. Of the nursing home residents, 15 had at least one fall, with a total of 37 falls recorded over 12 months. In the control group, no falls were recorded. The fall risk score was significantly different between nursing home residents and the control group (9.2 + 3.2 vs. 5.7 ± 2.2). Furthermore, the score significantly differentiated fallers from non-fallers (10.3 ± 1.8 vs. 5.2 ± 2.5), with a cut-off > 7.5 (AUC: 0.95) and a sensitivity of 86.7% (specificity 83.3%). The fall risk score is able to detect the difference between senior nursing home residents and young, healthy controls, as well as between fallers and non-fallers. Its main proof of concept is demonstrated, as based on movement data outside special gait labs, and it can simplify the risk of fall determination in geriatric nursing home residents and can now be used in further, prospective studies.

Age-related adaptation of the body's kinematic responses to unpredictable trip perturbations induced by a split-belt treadmill. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38083763 DOI: 10.1109/embc40787.2023.10340651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

This study quantitatively investigated motor adaptations to unpredictable trip perturbations repeatedly induced by a commercially available split-belt treadmill. Using a motion capture system, three outcome measures (i.e., maximum trunk flexion angle, maximum right hip flexion angle, and minimum whole-body center of mass (COM) position) quantified the kinematics of 10 healthy young (YG) and 10 healthy older adult (OG) groups. In each of the five trials, random trip perturbations were induced between the 31st and 40th steps. The three outcome measures were computed for the pre-trip period (from the baseline gait to the five steps before the trip perturbation) and the recovery period (after the trip perturbation to the baseline gait). The results showed that both groups progressively adapted the body's kinematic responses to the repetitive trip perturbations. The findings suggest that our trip-inducing technology may train young and older adults to improve the body's kinematic responses and reduce the risk of falling.

Computational assessment on the impact of collagen fiber orientation in cartilages on healthy and arthritic knee kinetics/kinematics

BACKGROUND

The inhomogeneous distribution of collagen fiber in cartilage can substantially influence the knee kinematics. This becomes vital for understanding the mechanical response of soft tissues, and cartilage deterioration including osteoarthritis (OA). Though the conventional computational models consider geometrical heterogeneity along with fiber reinforcements in the cartilage model as material heterogeneity, the influence of fiber orientation on knee kinetics and kinematics is not fully explored. This work examines how the collagen fiber orientation in the cartilage affects the healthy (intact knee) and arthritic knee response over multiple gait activities like running and walking.

METHODS

A 3D finite element knee joint model is used to compute the articular cartilage response during the gait cycle. A fiber-reinforced porous hyper elastic (FRPHE) material is used to model the soft tissue. A split-line pattern is used to implement the fiber orientation in femoral and tibial cartilage. Four distinct intact cartilage models and three OA models are simulated to assess the impact of the orientation of collagen fibers in a depth wise direction. The cartilage models with fibers oriented in parallel, perpendicular, and inclined to the articular surface are investigated for multiple knee kinematics and kinetics.

FINDINGS

The comparison of models with fiber orientation parallel to articulating surface for walking and running gait has the highest elastic stress and fluid pressure compared with inclined and perpendicular fiber-oriented models. Also, the maximum contact pressure is observed to be higher in the case of intact models during the walking cycle than for OA models. In contrast, the maximum contact pressure is higher during running in OA models than in intact models. Additionally, parallel-oriented models produce higher maximum stresses and fluid pressure for walking and running gait than proximal-distal-oriented models. Interestingly, during the walking cycle, the maximum contact pressure with intact models is approximately three times higher than on OA models. In contrast, the OA models exhibit higher contact pressure during the running cycle.

INTERPRETATION

Overall, the study indicates that collagen orientation is crucial for tissue responsiveness. This investigation provides insights into the development of tailored implants.

Relationship between Muscle Strength and Gait Parameters in Healthy Older Women and Men

Maintaining sufficient muscle strength is fundamental to prevent a decline in basic physical functions such as gait, and is therefore a prerequisite for a healthy independent life in older people. However, the relationship between gait parameters and the strength of single muscle groups is reported with inconclusive results. The objective of this study was to analyze the relationship of strength of nine single muscle groups of lower and upper leg muscles as well as handgrip strength for gait parameters in older adults. Sixty-nine independently living older adults participated in the study. Maximum ankle plantar- and dorsiflexion, knee flexion and extension, as well as hip abduction, adduction, flexion, and extension strength, were measured using an isokinetic dynamometer. Additionally, hand grip strength measured via a hand dynamometer was obtained. Walking gait parameters were recorded with a 3D motion capture system on an instrumented treadmill. The relationships between multiple strength and gait variables were analyzed by Pearson's correlation coefficient. Linear regression analyses were performed to identify the predictive ability of muscle strength (normalized to body weight) for gait speed, stride time, stance time, stride length and step width. Multiple significant weak to moderate positive ([r = 0.343, p = 0.047]-[r = 0.538, p = 0.002]) and negative ([r = -0.340, p = 0.046]-[r = 0.593, p = 0.001]) correlations that were unequally distributed between both sexes were detected. Significant regression models explained ([r² = 16.6%, p = 0.015]-[r² = 44.3 %, p = 0.003]) and ([r² = 21.8%, p = 0.022]-[r² = 36.1%, p = 0.044]) of the gait parameter variations for men and women, respectively. The results suggest a sex-specific relevance of single muscle groups for all gait parameters. This may be attributed to anatomical differences and it is important to prevent strength-related changes in gait parameters.

Gait Improvement by Alerted Push-Off via Heating of Insole Tip

This study investigated the change in the joint angles of the lower limb during gait by heating the tip of the insole to make a conscious push-off with the warm part. Fifteen healthy males performed treadmill walking under three different conditions: CONTROL walked as usual, INST was instructed to extend the stride with a push-off from the ball of foot to the toe, and HEAT was asked to walk while attempting to push off the warm area, which was attached to the disposable warmer to the area from the ball of foot to the toe of the insole. A 3D-motion capture system with infrared cameras was used to analyze the gait. The hip joint angle increased significantly under the INST and HEAT. Although the ankle dorsi-flexion at heel strike did not differ significantly for these conditions, ankle plantar-flexion significantly increased at toe-off under the INST and HEAT. Especially, effect size (d) in increased plantar-flexion was large in HEAT (=1.50), whereas it was moderate in INST (=0.68). These results suggest that a heated stimulus during gait enhanced the consciousness of push-off and increased leg swing and ankle plantar-flexion during the terminal stance phase, which may increase the stride length.

The effect of rocker sole shoes on ground reaction force in the elderly

Aging is associated with decreases in gait performance and mobility. Toe-only rocker sole is prescribed as a common shoe modification in restricted foot and ankle joints mobility. Therefore, this study aimed to determine the effect of toe-only rocker sole shoes on the ground reaction force (GRF) in the elderly. Twenty-one older adults walked on a walkway equipped with one force plate under six different conditions including barefoot (BF), normal shoe (NS), and four types of toe-only rocker sole shoes (RS) with various degrees of rocker angle (RS10, RS20, RS30, and RS40). The peaks of the GRFs in three planes were obtained. Different rocker angles could affect GRF parameters. The first peak of GRF (FZ1) significantly increased with both RS30 and RS40 compared to BF, NS, RS10, and RS20. FZ1 significantly decreased with RS30 compared to RS40. The braking force (FX1) was significantly lower with NS compared to RS30 and RS40. FX1 was significantly higher with RS40 compared to the other shoe conditions. The propulsive force (FX2) significantly decreased during walking with BF compared to NS, RS20, RS30, and RS40. A higher FX2 was observed in RS40 than the other shoe conditions except RS30. Also, FX2 was significantly lower with RS10 compared to RS30. Increasing rocker angle may result in an increase in the peak magnitude of FZ1, FX1, FX2 in the elderly without any improvement in walking speed.

Reliability of Smartphone Accelerometers for Measuring Gait During Data Collection Over Zoom

This study examined whether gait data could be reliably collected by homebound participants using iPhones under online supervision. Eighteen healthy young adults met with investigators through Zoom and installed an app to record acceleration from their iPhones' accelerometers. Half of the subjects walked normally; the other half walked while spelling words backward. During the gait tasks subjects recorded their anterior-posterior (AP), medial-lateral (ML), and vertical (V) accelerations. Data collection was repeated the following week. Seven maximum and minimum peak accelerations in the AP, ML, and vertical directions associated with events in gait were determined. Significant main effects of week and direction were observed for the first and second vertical acceleration measures. Cronbach alpha values were >0.60 for all acceleration measures, but the maximum and minimum AP accelerations that showed fair to good levels of consistency. The findings suggest gait data collected inside the home setting may be of clinical use.

Association of mobility capacity with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in community-dwelling older adults

We examined the association of mobility capacity with muscle thicknesses and echo intensities of the trunk and lower extremity muscles measured using an ultrasound imaging device in community-dwelling older adults. The participants were 57 community-dwelling older adults. Mobility capacity was assessed based on the measurement of usual and maximal walking speeds and timed up-and-go (TUG) time. Muscle thickness and echo intensity of the trunk and lower extremity muscles were measured using an ultrasound imaging device. Finally, sagittal spinal alignment was assessed based on the measurement of thoracic kyphosis, lumbar lordosis, and sacral anterior inclination angles in the standing position using a Spinal Mouse. Stepwise regression analysis showed that the tibialis anterior muscle thickness, tibialis posterior muscle echo intensity, and body weight were significant and independent factors of usual walking speed, with a coefficient of determination (R²) of 0.25. The thicknesses of the thoracic erector spinae and obliquus externus abdominis muscles were significant and independent factors of maximal walking speed (R² = 0.26). Moreover, only age was a significant and independent factor for TUG time (R² = 0.10). The results of this study suggested associations 1) between slow usual walking speed and low tibialis anterior muscle thicknesses and high echo intensity of the tibialis posterior muscle and 2) between slow maximal walking speed and low thoracic erector spinae and obliquus externus abdominis thicknesses in community-dwelling older adults.

Modeling Functional Limitations, Gait Impairments, and Muscle Pathology in Alzheimer's Disease: Studies in the 3xTg-AD Mice

Gait impairments in Alzheimer's disease (AD) result from structural and functional deficiencies that generate limitations in the performance of activities and restrictions in individual's biopsychosocial participation. In a translational way, we have used the conceptual framework proposed by the International Classification of Disability and Health Functioning (ICF) to classify and describe the functioning and disability on gait and exploratory activity in the 3xTg-AD animal model. We developed a behavioral observation method that allows us to differentiate qualitative parameters of psychomotor performance in animals' gait, similar to the behavioral patterns observed in humans. The functional psychomotor evaluation allows measuring various dimensions of gait and exploratory activity at different stages of disease progression in dichotomy with aging. We included male 3xTg-AD mice and their non-transgenic counterpart (NTg) of 6, 12, and 16 months of age (n = 45). Here, we present the preliminary results. The 3xTg-AD mice show more significant functional impairment in gait and exploratory activity quantitative variables. The presence of movement limitations and muscle weakness mark the functional decline related to the disease severity stages that intensify with increasing age. Motor performance in 3xTg-AD is accompanied by a series of bizarre behaviors that interfere with the trajectory, which allows us to infer poor neurological control. Additionally, signs of physical frailty accompany the functional deterioration of these animals. The use of the ICF as a conceptual framework allows the functional status to be described, facilitating its interpretation and application in the rehabilitation of people with AD.

An Analytical Insight Into How Walking Speed and Spatial and Temporal Symmetry Are Related to Ankle Dysfunctions in Children With Hemiplegic Cerebral Palsy

OBJECTIVE

The aim of the study was to identify the major determining factors among ankle dysfunctions for walking speed and symmetry in children with hemiplegic cerebral palsy.

DESIGN

This was a prospective analysis that included 52 children with hemiplegic cerebral palsy, aged between 5 and 8 yrs, had mild spasticity, and were functioning at Gross Motor Function Classification System level I or II. The dorsiflexor and plantar flexor strength, dynamic spasticity (represented by gastrocnemius muscle lengthening velocity during stance phase), plantar flexors stiffness, ankle joint position sense, and walking performance (spatiotemporal parameter) were assessed.

RESULTS

The least absolute shrinkage and selection operator regression analyses showed that the dorsiflexor strength of the paretic limb was the major determining factor of walking speed (R2 = 0.38, P < 0.001). Dynamic spasticity of the plantar flexors explained a portion of the variance in walking speed (R2 = 0.15, P < 0.001) and the highest portion of the variance in spatial walking symmetry (R2 = 0.18, P = 0.002). In addition, the ankle joint position sense was the primary determinant of temporal walking symmetry (R2 = 0.10, P = 0.021).

CONCLUSIONS

In children with hemiplegic cerebral palsy, walking speed is mostly influenced by dorsiflexor muscle strength, temporal walking symmetry is associated with the joint position sense, whereas spatial walking symmetry is explicated by the dynamic spasticity of the plantar flexor muscles.

Editorial Commentary: How Far Can the Arthroscope Reach in the Ankle Joint?

Surgical access to pathology of the talar dome (e.g., osteochondral lesions of the talus) can be limited because of the ankle joint congruity. When considering arthroscopic treatment, anterior arthroscopy with the ankle in plantar flexion or posterior arthroscopy with the ankle in dorsiflexion is used. The surgeon should carefully assess different clinical and radiologic aspects to plan the optimal operative approach. Meticulous physical examination, including ankle range of motion and possible palpation of a talar lesion, in combination with exact lesion localization on computed tomography or magnetic resonance imaging usually provide sufficient preoperative information. Most lesions with the anterior border localized on or anterior to the midline of the talus are accessible by anterior arthroscopy. In the case of preoperative doubt concerning the intraoperative accessibility, a computed tomography scan of the ankle in full plantarflexion is used to mirror arthroscopic reachability. Intraoperative surgical tricks to increase accessibility to the lesion may consist of an adjunct soft-tissue distraction device, reduction of the distal tibial rim, and treating the lesion from anteriorly to posteriorly, thereby gaining further exposure to the lesion throughout the procedure.

Effect of walking speed during gait in water of healthy elderly

BACKGROUND

Walking in water (WW) is frequently used as an aquatic exercise in rehabilitation programs for the elderly. Understanding gait characteristics of WW is of primary importance to effectively design specific water-based rehabilitation programs. Moreover, as walking speed in water is reduced with a possible effect on gait parameters, the age- and environment-related changes during WW have to be investigated considering the effects of instantaneous walking speed.

RESEARCH QUESTION

how do gait kinematic characteristics differ in healthy elderly between WW and on land walking condition (LW)? Do elderly show different walking patterns compared to young adults? Can these kinematic changes be accounted only by the different environment/age or are they also related to walking speed?

METHODS

Nine healthy elderly participants (73.5 ± 5.8 years) were acquired during walking in WW and LW at two different speeds. Kinematic parameters were assessed with waterproofed inertial magnetic sensors using a validated protocol. The influence of environment, age and walking speed on gait parameters was investigated with linear mixed models.

RESULTS

Shorter stride distances and longer stride durations were observed in WW compared to LW. In the sagittal plane, hip and knee joint showed larger flexion in WW (>10deg over the whole stride and ∼28deg at foot strike, respectively). Furthermore, lower walking speeds and stride distances were observed in elderly compared to young adults. In the sagittal plane, a slightly more flexed hip joint and a less plantarflexed ankle joint (∼9 deg) were observed in the elderly.

SIGNIFICANCE

The results showed the importance of assessing the walking speed during WW, as gait parameters can vary not only for the effect environment but also due to different walking speeds.

Two-dimensional video gait analysis: A systematic review of reliability, validity, and best practice considerations

BACKGROUND

Motion capture systems are widely used to quantify human gait. Two-dimensional (2D) video systems are simple to use, easily accessible, and affordable. However, their performance as compared to other systems (i.e. three-dimensional (3D) gait analysis) is not well established.

OBJECTIVES

This work provides a comprehensive review of design specifications and performance characteristics (validity and reliability) of two-dimensional motion capture systems.

STUDY DESIGN

Systematic review.

METHODS

A systematic literature search was conducted in three databases from 1990 to 2019 and identified 30 research articles that met the inclusion/exclusion criteria.

RESULTS

Reliability of measurements of two-dimensional video motion capture was found to vary greatly from poor to excellent. Results relating to validity were also highly variable. Comparisons between the studies were challenging due to differences in protocols, instrumentation, parameters assessed, and analyses performed.

CONCLUSIONS

Variability in performance could be attributed to study design, gait parameters being measured, and technical aspects. The latter includes camera specifications (i.e. resolution and frame rate), setup (i.e. camera position), and analysis software. Given the variability in performance, additional validation testing may be needed for specific applications involving clinical or research-based assessments, including specific patient populations, gait parameters, mobility tasks, and data collection protocols.

CLINICAL RELEVANCE

This review article provides guidance on the application of 2D video gait analysis in a clinical or research setting. While not suitable in all instances, 2D gait analysis has promise in specific applications. Recommendations are provided about the patient populations, gait parameters, mobility tasks, and data collection protocols.

New assistive walker improved local dynamic stability in young healthy adults

In this study, we investigated the effect of walker type on gait pattern characteristics comparing normal gait (NG), gait with a regular walker (RW), and gait with a newly developed walker with vertical moveable handlebars, the Crosswalker (CW). Partial weight bearing (PWB) of the feet, peak joint angles and largest Lyapunov exponent (λ_max) of the lower extremities (hip, knee, ankle) in the sagittal plane, and gait parameters (gait velocity, stride length, cadence, stride duration) were determined for 18 healthy young adults performing 10 walking trials for each walking condition. Assistive gait with the CW improved local dynamic stability in the lower extremities (hip, knee, ankle) compared with RW and was not significantly different from NG. However, peak joint angles and stride characteristics in CW were different from NG. The PWB on the feet was lower with the RW (70.3%) compared to NG (82.8%) and CW (80.9%). This improved stability may be beneficial for the elderly and patients with impaired gait. However, increased PWB is not beneficial for patients during the early stages of rehabilitation.

Are Accelerometer-based Functional Outcome Assessments Feasible and Valid After Treatment for Lower Extremity Sarcomas?

BACKGROUND

Aspects of physical functioning, including balance and gait, are affected after surgery for lower limb musculoskeletal tumors. These are not routinely measured but likely are related to how well patients function after resection or amputation for a bone or soft tissue sarcoma. Small, inexpensive portable accelerometers are available that might be clinically useful to assess balance and gait in these patients, but they have not been well studied.

QUESTIONS/PURPOSES

In patients treated for lower extremity musculoskeletal tumors, we asked: (1) Are accelerometer-based body-worn monitor assessments of balance, gait, and timed up-and-go tests (TUG) feasible and acceptable? (2) Do these accelerometer-based body-worn monitor assessments produce clinically useful data (face validity), distinguish between patients and controls (discriminant validity), reflect findings obtained using existing clinical measures (convergent validity) and standard manual techniques in clinic (concurrent validity)?

METHODS

This was a prospective cross-sectional study. Out of 97 patients approached, 34 adult patients treated for tumors in the femur/thigh (19), pelvis/hip (3), tibia/leg (9), or ankle/foot (3) were included in this study. Twenty-seven had limb-sparing surgery and seven underwent amputation. Patients performed standard activities while wearing a body-worn monitor on the lower back, including standing, walking, and TUG tests. Summary measures of balance (area [ellipsis], magnitude [root mean square {RMS}], jerkiness [jerk], frequency of postural sway below which 95% of power of acceleration power spectrum is observed [f95 of postural sway]), gait [temporal outcomes, step length and velocity], and TUG time were derived. Body-worn monitor assessments were evaluated for feasibility by investigating data loss and patient-reported acceptability and comfort. In addition, outcomes in patients were compared with datasets of healthy participants collected in parallel studies using identical methods as in this study to assess discriminant validity. Body-worn monitor assessments were also investigated for their relationships with routine clinical scales (the Musculoskeletal Tumour Society Scoring system [MSTS], the Toronto Extremity Salvage Score [TESS], and the Quality of life-Cancer survivors [QoL-CS)] to assess convergent validity and their agreement with standard manual techniques (video and stopwatch) to assess concurrent validity.

RESULTS

Although this was a small patient group, there were initial indications that body-worn monitor assessments were well-tolerated, feasible to perform, acceptable to patients who responded (95% [19 of 20] of patients found the body-worn monitor acceptable and comfortable and 85% [17 of 20] found it user-friendly), and produced clinically useful data comparable with the evidence. Balance and gait measures distinguished patients and controls (discriminant validity), for instance balance outcome (ellipsis) in patients (0.0475 m/s [95% confidence interval 0.0251 to 0.0810]) was affected compared with controls (0.0007 m/s [95% CI 0.0003 to 0.0502]; p = 0.001). Similarly gait outcome (step time) was affected in patients (0.483 seconds [95% CI 0.451 to 0.512]) compared with controls (0.541 seconds [95% CI 0.496 to 0.573]; p < 0.001). Moreover, body-worn monitor assessments showed relationships with existing clinical scales (convergent validity), for instance ellipsis with MSTS (r = -0.393; p = 0.024). Similarly, manual techniques showed excellent agreement with body-worn monitor assessments (concurrent validity), for instance stopwatch time 22.28 +/- 6.93 seconds with iTUG time 21.18 +/- 6.23 seconds (intraclass correlation coefficient agreement = 0.933; p < 0.001). P < 0.05 was considered statistically significant.

CONCLUSIONS

Although we had a small, heterogeneous patient population, this pilot study suggests that body-worn monitors might be useful clinically to quantify physical functioning in patients treated for lower extremity tumors. Balance and gait relate to disability and quality of life. These measurements could provide clinicians with useful novel information on balance and gait, which in turn could guide rehabilitation strategies.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Music and Metronomes Differentially Impact Motor Timing in People with and without Parkinson's Disease: Effects of Slow, Medium, and Fast Tempi on Entrainment and Synchronization Performances in Finger Tapping, Toe Tapping, and Stepping on the Spot Tasks

Introduction

Rhythmic auditory stimulation (RAS) has successfully helped regulate gait for people with Parkinson's disease. However, the way in which different auditory cues and types of movements affect entrainment, synchronization, and pacing stability has not been directly compared in different aged people with and without Parkinson's. Therefore, this study compared music and metronomes (cue types) in finger tapping, toe tapping, and stepping on the spot tasks to explore the potential of RAS training for general use.

Methods

Participants (aged 18–78 years) included people with Parkinson's (n = 30, Hoehn and Yahr mean = 1.78), older (n = 26), and younger adult controls (n = 36), as age may effect motor timing. Timed motor production was assessed using an extended synchronization-continuation task in cue type and movement conditions for slow, medium, and fast tempi (81, 116, and 140 mean beats per minute, respectively).

Results

Analyses revealed main effects of cue and movement type but no between-group interactions, suggesting no differences in motor timing between people with Parkinson's and controls. Music supported entrainment better than metronomes in medium and fast tempi, and stepping on the spot enabled better entrainment and less asynchrony, as well as more stable pacing compared to tapping in medium and fast tempi. Age was not confirmed as a factor, and no differences were observed in slow tempo.

Conclusion

This is the first study to directly compare how different external auditory cues and movement types affect motor timing. The music and the stepping enabled participants to maintain entrainment once the external pacing cue ceased, suggesting endogenous mechanisms continued to regulate the movements. The superior performance of stepping on the spot suggests embodied entrainment can occur during continuous movement, and this may be related to emergent timing in tempi above 600 ms. These findings can be applied therapeutically to manage and improve adaptive behaviours for people with Parkinson's.

Percentage Contribution of Lower Limb Moments to Vertical Ground Reaction Force in Normal Gait

Objective

The purpose of this study was to investigate how the hip, knee, and ankle moments in the sagittal plane contribute to the vertical ground reaction force (GRF) in healthy participants during normal speed of walking.

Methods

Forty healthy male individuals volunteered to participate in this study. They were filmed using 6 high-speed (120 Hz) Pro-Reflex infrared cameras (Qualisys) while walking on an Advanced Mechanical Technology Incorporation force platform. The data collected were the percentage contribution of the moments of the hip, knee, and ankle joints in the sagittal plane at the instant of occurrence of the first peak, second peak, and trough of the vertical GRF.

Results

The results revealed that at the first peak of the GRF (loading response), the highest contribution was generated from the knee extension moment followed by the hip extension moment. Knee flexion and ankle plantar flexion moments produced a high contribution to the trough of the GRF (midstance) with approximately equal values. The second peak of the GRF was mainly produced by the ankle plantar flexion moment.

Conclusion

The role of hip extension moment is secondary to knee extension moment in the first peak of GRF. Knee flexion moment is secondary to ankle plantar flexion moment in the second peak of GRF. Both knee flexion and ankle plantar flexion moments have equal contribution during midstance.

The effects of mobile phone use on walking: a dual task study

OBJECTIVES

The aim of this study was to examine the effects of walking at different speeds while using a mobile phone on spatiotemporal stride parameters among young adults. Ten participants (7 male, 3 female; age = 24.7 ± 4.4 years, mean ± 1SD) completed 12 walking trials. Trials consisted of tasks performed at both normal and fast walking speeds-walking only, walking while texting, and walking while talking on a mobile phone. Gait velocity, stride length, cadence, and double support time were computed using data from accelerometers on either shoe.

RESULTS

The effects of distracted walking were not significantly larger when performed at a self-selected fast walking speed compared with a normal walking speed. However, walking while texting produced significant decreases in gait velocity, stride length, and cadence, with a significant increase in double support time at both walking speeds. Moreover texting increased the size of the relative variability of walking, observed through a significant increase in the coefficient of variation of cadence, stride length, and double support time. The observed changes may be suggestive of compromised balance when walking while texting regardless of walking speed. This may place the individual at a greater risk of, slips, trips and falls.

Gait-Assist Wearable Robot Using Interactive Rhythmic Stimulation to the Upper Limbs

Many power-assist wearable exoskeletons have been developed to provide walking support and gait rehabilitation for elderly subjects and gait-disorder patients. Most designers have focused on a direct power-assist to the wearer's lower limbs. However, gait is a coordinated rhythmic movement of four limbs controlled intrinsically by central pattern generators, with the upper limbs playing an important role in walking. Maintaining a normal gait can become difficult as a person ages, because of decreases in limb coordination, stride length, and gait speed. It is known that coordination mechanisms can be governed by the principle of mutual entrainment, in which synchronization develops through the interaction between nonlinear phase oscillators in biological systems. This principle led us to hypothesize that interactive rhythmic stimulation to upper-limb movements might compensate for the age-related decline in coordination, thereby improving the gait in the elderly. To investigate this hypothesis, we developed a gait-assist wearable exoskeleton that employs interactive rhythmic stimulation to the upper limbs. In particular, we investigated the effects on spatial (i.e., hip-swing amplitude) and temporal (i.e., hip-swing period) gait parameters by conducting walking experiments with 12 healthy elderly subjects under one control condition and five upper-limb-assist conditions, where the output motor torque was applied at five different upper-limb swing positions. The results showed a statistically significant increase in the mean hip-swing amplitude, with a mean increment of about 7% between the control and upper-limb-assist conditions. They also showed a statistically significant decrease in the mean hip-swing period, with a mean decrement of about 2.3% between the control and one of the upper-limb-assist conditions. Although the increase in the hip-swing amplitude and the decrease in the hip-swing period were both small, the results indicate the possibility that interactive rhythmic stimulation to the upper limbs might have a positive effect on the gait of the elderly.

The Relationship between Walking Speed and Step Length in Older Aged Patients

Compared with elderly people who have not experienced falls, those who have were reported to have a shortened step length, large fluctuations in their pace, and a slow walking speed. The purpose of this study was to elucidate the step length required to maintain a walking speed of 1.0 m/s in patients aged 75 years or older. We measured the 10 m maximum walking speed in patients aged 75 years or older and divided them into the following two groups: Those who could walk 1.0 m/s or faster (fast group) and those who could not (slow group). Step length was determined from the number of steps taken during the 10 m-maximum walking speed test, and the step length-to-height ratio was calculated. Isometric knee extension muscle force (kgf), modified functional reach (cm), and one-leg standing time (s) were also measured. We included 261 patients (average age: 82.1 years, 50.6% men) in this study. The fast group included 119 participants, and the slow group included 142 participants. In a regression logistic analysis, knee extension muscle force (p = 0.03) and step length-to-height ratio (p < 0.01) were determined as factors significantly related to the fast group. As a result of ROC curve analysis, a step length-to-height ratio of 31.0% could discriminate between the two walking speed groups. The results suggest that the step length-to-height ratio required to maintain a walking speed of 1.0 m/s is 31.0% in patients aged 75 years or older.

Mobility related physical and functional losses due to aging and disease - a motivation for lower limb exoskeletons

BACKGROUND

Physical and functional losses due to aging and diseases decrease human mobility, independence, and quality of life. This study is aimed at summarizing and quantifying these losses in order to motivate solutions to overcome them with a special focus on the possibilities by using lower limb exoskeletons.

METHODS

A narrative literature review was performed to determine a broad range of mobility-related physical and functional measures that are affected by aging and selected cardiovascular, respiratory, musculoskeletal, and neurological diseases.

RESULTS

The study identified that decreases in limb maximum muscle force and power (33% and 49%, respectively, 25-75 yrs) and in maximum oxygen consumption (40%, 20-80 yrs) occur for older adults compared to young adults. Reaction times more than double (18-90 yrs) and losses in the visual, vestibular, and somatosensory systems were reported. Additionally, we found decreases in steps per day (75%, 60-85 yrs), maximum walking speed (24% 25-75 yrs), and maximum six-minute and self-selected walking speed (38% and 21%, respectively, 20-85 yrs), while we found increases in the number of falls relative to the number of steps per day (800%), injuries due to falls (472%, 30-90 yrs) and deaths caused by fall (4000%, 65-90 yrs). Measures were identified to be worse for individuals with impaired mobility. Additional detrimental effects identified for them were the loss of upright standing and locomotion, freezing in movement, joint stress, pain, and changes in gait patterns.

DISCUSSION

This review shows that aging and chronic conditions result in wide-ranging losses in physical and sensory capabilities. While the impact of these losses are relatively modest for level walking, they become limiting during more demanding tasks such as walking on inclined ground, climbing stairs, or walking over longer periods, and especially when coupled with a debilitating disease. As the physical and functional parameters are closely related, we believe that lost functional capabilities can be indirectly improved by training of the physical capabilities. However, assistive devices can supplement the lost functional capabilities directly by compensating for losses with propulsion, weight support, and balance support.

CONCLUSIONS

Exoskeletons are a new generation of assistive devices that have the potential to provide both, training capabilities and functional compensation, to enhance human mobility.

Automatic Musculoskeletal and Neurological Disorder Diagnosis With Relative Joint Displacement From Human Gait

Musculoskeletal and neurological disorders are common devastating companions of ageing, leading to a reduction in quality of life and increased mortality. Gait analysis is a popular method for diagnosing these disorders. However, manually analyzing the motion data is a labor-intensive task, and the quality of the results depends on the experience of the doctors. In this paper, we propose an automatic framework for classifying musculoskeletal and neurological disorders among older people based on 3D motion data. We also propose two new features to capture the relationship between joints across frames, known as 3D Relative Joint Displacement (3DRJDP) and 6D Symmetric Relative Joint Displacement (6DSymRJDP), such that the relative movement between joints can be analyzed. To optimize the classification performance, we adapt feature selection methods to choose an optimal feature set from the raw feature input. Experimental results show that we achieve a classification accuracy of 84.29% using the proposed relative joint features, outperforming existing features that focus on the movement of individual joints. Considering the limited open motion database for gait analysis focusing on such disorders, we construct a comprehensive, openly accessible 3D full-body motion database from 45 subjects.

Scanning Laser Rangefinders for the Unobtrusive Monitoring of Gait Parameters in Unsupervised Settings

Since variations in common gait parameters (such as cadence, velocity and stride-length) of elderly people are a reliable indicator of functional and cognitive decline in aging and increased fall risks, such gait parameters have to be monitored continuously to enable preventive interventions as early as possible. With scanning laser rangefinders (SLR) having been shown to be suitable for standardised (frontal) gait assessments, this article introduces an unobtrusive gait monitoring (UGMO) system for lateral gait monitoring in homes for the elderly. The system has been evaluated in comparison to a GAITRite (as reference system) with 86 participants (ranging from 21 to 82 years) passing the 6-min walk test twice. Within the considered 56,351 steps within an overall 7877 walks and approximately 34 km distance travelled, it has been shown that the SLR Hokuyo UST10-LX is more sensitive than the cheaper URG-04LX version in regard to the correct (automatic) detection of lateral steps (98% compared to 77%) and walks (97% compared to 66%). Furthermore, it has been confirmed that the UGMO (with the SLR UST10-LX) can measure gait parameters such as gait velocity and stride length with sufficient sensitivity to determine age- and disease-related functional (and cognitive) decline.

Effects of Slipper Features and Properties on Walking and Sit-to-Stand Tasks of Older Women

Indoor slippers with a strap across the dorsal forefoot are popular with older women. However, their influence on the foot motion has not been reported. This study evaluated the range of movement in the knee and ankle joints during walking and changes in trunk displacement during sit-to-stand when 10 healthy older women wore two types of slippers and were barefoot. Compared to barefeet, walking in slippers results in significant increases in the knee flexion angle in the swing phase. However, there is nonsignificant differences in the ankle angle in any phase across all conditions. During the sit-stand transition when slippers are worn, there is a significant reduction in the peak trunk tilt angle and range, as well as the duration of the weight shift when motion is initiated. The findings therefore provide a better understanding of slipper features and designs associated with changes in foot kinematics in older women.

Optimal Mixed Tracking/Impedance Control With Application to Transfemoral Prostheses With Energy Regeneration

OBJECTIVE

We design an optimal passivity-based tracking/impedance control system for a robotic manipulator with energy regenerative electronics, where the manipulator has both actively and semi-actively controlled joints. The semi-active joints are driven by a regenerative actuator that includes an energy-storing element.

METHOD

External forces can have a large influence on energy regeneration characteristics. Impedance control is used to impose a desired relationship between external forces and deviation from reference trajectories. Multi-objective optimization (MOO) is used to obtain optimal impedance parameters and control gains to compromise between the two conflicting objectives of trajectory tracking and energy regeneration. We solve the MOO problem under two different scenarios: 1) constant impedance; and 2) time-varying impedance.

RESULTS

The methods are applied to a transfemoral prosthesis simulation with a semi-active knee joint. Normalized hypervolume and relative coverage are used to compare Pareto fronts, and these two metrics show that time-varying impedance provides better performance than constant impedance. The solution with time-varying impedance with minimum tracking error (0.0008 rad) fails to regenerate energy (loses 9.53 J), while a solution with degradation in tracking (0.0452 rad) regenerates energy (gains 270.3 J). A tradeoff solution results in fair tracking (0.0178 rad) and fair energy regeneration (131.2 J).

CONCLUSION

Our experimental results support the possibility of net energy regeneration at the semi-active knee joint with human-like tracking performance.

SIGNIFICANCE

The results indicate that advanced control and optimization of ultracapacitor-based systems can significantly reduce power requirements in transfemoral prostheses.

Inter-segmental motions of the foot: differences between younger and older healthy adult females

BACKGROUND

Although accumulative evidence exists that support the applicability of multi-segmental foot models (MFMs) in evaluating foot motion in various pathologic conditions, little is known of the effect of aging on inter-segmental foot motion. The objective of this study was to evaluate differences in inter-segmental motion of the foot between older and younger adult healthy females during gait using a MFM with 15-marker set.

METHODS

One hundred symptom-free females, who had no radiographic evidence of osteoarthritis, were evaluated using MFM with 15-marker set. They were divided into young (n = 50, 20-35 years old) and old (n = 50, 60-69 years old) groups. Coefficients of multiple correlations were evaluated to assess the similarity of kinematic curve. Inter-segmental angles (hindfoot, forefoot, and hallux) were calculated at each gait phase. To evaluate the effect of gait speed on intersegmental foot motion, subgroup analysis was performed according to the similar speed of walking.

RESULTS

Kinematic curves showed good or excellent similarity in most parameters. Range of motion in the sagittal (p < 0.001) and transverse (p = 0.001) plane of the hallux, and sagittal (p = 0.023) plane of the forefoot was lower in older females. The dorsiflexion (p = 0.001) of the hallux at terminal stance and pre-swing phases was significantly lower in older females. When we compared young and older females with similar speed, these differences remained.

CONCLUSIONS

Although the overall kinematic pattern was similar between young and older females, reduced range of inter-segmental motion was observed in the older group. Our results suggest that age-related changes need to be considered in studies evaluating inter-segmental motion of the foot.

Walking a mile in another's shoes: The impact of wearing an Age Suit

The "Age Suit" described in this article was developed to enable future designers, business leaders, and engineers to experience navigating the world as many older adults must. Tools such as this Age Suit offer the opportunity to "walk a mile" in another's shoes to develop empathy that can result in better design of spaces, goods, and services to meet the needs of a rapidly growing older population. This work first examined, through a series of clinical tests, whether younger adults' physical capacities were reduced in a direction consistent with aging by wearing a suit developed by the MIT AgeLab. An experiential learning task was then completed with the suit to understand its impact on completion of an instrumental activity of daily living. Results showed that younger adults wearing the suit experienced changes in task performance consistent with expected changes associated with aging. Participants' self-reports from the experiential learning task indicated that they were able to empathize with older adults regarding some issues they face while completing a grocery shopping task. Future research with the suit should involve a wider range of individuals from the population and examine what effect participants' levels of fitness have on the experience of wearing the suit.

Spatial and temporal gait characteristics of elderly individuals during backward and forward walking with shoes and barefoot

Backward walking (BW) is an inherent component of mobility and function in daily activities, particularly indoors, when it is more likely that a person is barefoot. No studies to date have compared the spatio-temporal characteristics of BW with and without shoes in elderly individuals. This study compared spatio-temporal measures of BW and forward walking (FW) among elderly individuals while barefoot or wearing shoes. Forty-seven elderly individuals (13 men and 34 women, 76.7±7.7years of age) were evaluated. Participants were requested to walk at a comfortable, self-selected pace across the GAITRite^® walkway for three trials under each of four conditions: walking forward (FW) and BW wearing their own comfortable low-heeled walking shoes and FW and BW walking without shoes. Gait speed, stride length and cadence were significantly reduced in BW versus FW, with an increase in double limb support (DLS), both with and without shoes. Barefoot BW resulted in significantly increased gait speed and cadence, and decreased DLS compared to BW with shoes. BW stride length was not affected by footwear. While barefoot FW was also associated with a significant increase in cadence and decrease in DLS time compared to walking with shoes, it decreased stride length and had no detrimental effect on gait speed. Assessment of the spatio-temporal parameters of walking barefoot and with shoes during FW and BW can contribute to our understanding of the ability of elderly individuals to adapt to changing walking conditions, and should be included in the assessment of functional mobility of elderly individuals.

Relationships among exercise capacity, dynamic balance and gait characteristics of Nigerian patients with type-2 diabetes: an indication for fall prevention

This study investigated the relationships among exercise capacity (EC), dynamic balance (DB), and gait characteristics (GCs) of patients with type-2 diabetes (T2D) and healthy controls (HCs). This observational controlled study involved 125 patients with T2D receiving treatment at a Nigerian university teaching hospital and 125 apparently healthy patients' relatives and hospital staff recruited as controls. EC maximum oxygen consumption (VO2max) was estimated following a 6-min walk test. DB and GC were assessed using the Time Up to Go Test and an accelerometer (BTS G-Walk) assessing gait speed, step length, stride length, and cadence respectively during a self-selected walk. Data were analyzed using descriptive and inferential statistics. Alpha level was set at P<0.05. The mean ages of patients with T2D and HCs were 57.6±6.6 and 60.0±7.0 years, respectively. All physical characteristics were comparable (P>0.05). There were significant differences in the VO2max and DB between patients with T2D and HCs; 7.6±0.6 mL/kg/min vs. 9.6±0.6 mL/kg/min (t=-16.6, P=0.001) and 14.2±2.1 sec vs. 10.4±1.5 sec (t=-6.37, P=0.001), respectively. Furthermore, significant differences were found in GC between patients with T2D and HCs; gait speed: 0.7±0.1 m/sec vs. 1.2±0.1 m/sec (t=-16.60, P=0.001), step length: 0.6±0.2 m vs. 0.9±0.3 m (t=-7.56, P=0.001) and stride length: 0.9±0.1 m vs. 1.1±0.5 m (t=-6.09, P=0.001). There were significant correlations between EC and gait speed in both groups (T2D: r=-0.26, P=0.032 and HCs: r=0.51, P=0.003). In conclusion, patients with T2D demonstrated lower EC, unstable DB, and altered GCs compared with HCs. Exercise interventions to improve EC and gait balance are recommended.

MULTI-SEGMENTED TRUNK MOTION OF HEALTHY NON-ELDERLY ADULTS IN DIFFERENT DECADES OF LIFE

Traditionally, gait analysis models the trunk as one rigid body segment. This approach has limitations; it does not capture all the movements of this area of the body throughout locomotion. Lower-extremity-gait kinematics do not routinely change in healthy non-elderly adults in different decades of life; however, it is unknown if trunk kinematics will be altered during different activities of daily living as a function of age. The purpose of this study was to determine if a previously validated multi-segmented trunk model would detect trunk movement variations in non-elderly healthy adults in different decades of life. Thirty-four non-elderly healthy adults in various decades of life (20-29 years, 30-39 years, 40-49 years, and 50-59 years) completed two tasks of ambulatory daily living (level walking and stair descent). Trunk maximum angle during the gait cycle, timing of the trunk maximum angle during the gait cycle and trunk range of motion were examined using analysis of variance procedures. Findings are that age group did not affect the trunk kinematics of individuals in different decades of life, but that may not represent the experiences of elderly individuals.

GAIT ANALYSIS: SYSTEMS, TECHNOLOGIES, AND IMPORTANCE

Human gait is the identity of a person's style and quality of life. Reliable cognition of gait properties over time, continuous monitoring, accuracy of evaluation, and proper analysis of human gait characteristics have demonstrated their importance not only in clinical and medical studies, but also in the field of sports, rehabilitation, training, and robotics research. Focusing on walking gait, this study presents an overview on gait mechanisms, common technologies used in gait analysis, and importance of this particular field of research. Firstly, available technologies that involved in gait analysis are briefly introduced in this paper by concentrating on the usability and limitations of the systems. Secondly, key gait parameters and motion characteristics are elucidated from four angles of views; one: gait phases and gait properties; two: center of mass and center of pressure (CoM-CoP) tracking profile; three: Ground Reaction Force (GRF) and impact, and four: muscle activation. Thirdly, the study focuses on the clinical observations of gait patterns in diagnosing gait abnormalities of impaired patients. The presentation also shows the importance of gait analysis in sports to improve performance as well as to avoid risk of injuries of sports personnel. Significance of gait analysis in robotic research is also illustrated in this part where the study focuses on robot assisted systems and its possible applicability in clinical rehabilitation and sports training.

Spontaneous Improvement of Compensatory Knee Flexion After Surgical Correction of Mismatch Between Pelvic Incidence and Lumbar Lordosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to investigate the correlation between pelvic incidence (PI) and lumbar lordosis (LL) mismatch and knee flexion during standing in patients with lumbar degenerative diseases and to examine the effects of surgical correction of the PI-LL mismatch on knee flexion.

SUMMARY OF BACKGROUND DATA

Only several studies focused on knee flexion as a compensatory mechanism of the PI-LL mismatch. Little information is currently available on the effects of lumbar correction on knee flexion in patients with the PI-LL mismatch.

METHODS

A group of patients with lumbar degenerative diseases were divided into PI-LL match group (PI-LL ≤ 10°) and PI-LL mismatch group (PI-LL > 10°). A series of radiographic parameters and knee flexion angle (KFA) were compared between the two groups. The PI-LL mismatch group was further subdivided into operative and nonoperative group. The changes in KFA with PI-LL were examined.

RESULTS

The PI-LL mismatch group exhibited significantly greater sagittal vertical axis (SVA), pelvic tilt (PT) and KFA, and smaller LL, thoracic kyphosis (TK), and sacral slope than the PI-LL match group. PI-LL, LL, PI, SVA, and PT were significantly correlated with KFA in the PI-LL mismatch group. From baseline to 6-month follow-up, all variables were significantly different in the operative group with the exception of PI, although there was no significant difference in any variable in the nonoperative group. The magnitude of surgical correction in the PI-LL mismatch was significantly correlated with the degree of spontaneous changes in KFA, PT, and TK.

CONCLUSION

The PI-LL mismatch would contribute to compensatory knee flexion during standing in patients with lumbar degenerative disease. Surgical correction of the PI-LL mismatch could lead to a spontaneous improvement of compensatory knee flexion. The degree of improvement in knee flexion depends in part on the amount of correction in the PI-LL mismatch.

LEVEL OF EVIDENCE

3.

Effect of compensation procedures for velocity on repeatability and variability of gait parameters in normal subjects

Objective: To evaluate the effects of a mathematical procedure that adjusts for gait velocity on the variability seen in gait analysis.

Design: Evaluation before and after compensation.

Setting: Gait laboratory, Fukui University Hospital, Japan.

Subjects: Fourteen normal volunteers.

Outcome measures: A computerized gait analysis system with two forceplates and a light source spot measuring device was used. Gait measurement in each subject was performed on three different days.

Results: The gait parameters measured on three different days were significantly different, particularly step length, stride length, velocity, the components of floor-reaction forces and hip motion. In these parameters, intraclass correlation coefficient, ICC (1,1) was not high (range 0.05-0.71). However, there was a high correlation between these parameters and velocity and high repeatability was obtained following compensation for velocity (ICC (1,1), range 0.73-0.97). In contrast, compensation of parameters whose measurement was not significantly different before compensation did not improve ICC (1,1). Variability of all parameters was acceptable, however CV (an index of variability) improved significantly after compensation compared with that before compensation in six of 15 parameters.

Conclusions: Our findings suggest that low repeatability in gait parameters should be considered even when the gait of normal subjects is measured on different days. A high repeatability and more acceptable variability were obtained when the data were compensated for velocity.

Effects of low light on the stability of the head and pelvis of the healthy elderly

[Purpose] The purpose of this study was to evaluate the changes in body stability of the elderly while walking on even surface ground under low light. [Subjects] Ten young males and ten elderly males participated in this experiment. [Methods] Each subject walked along a 7 m walkway five times at their preferred walking speed under normal (>300 lux, NORM) and low light conditions (<5 lux, LOW). To compare the changes in body stability, the root mean square of acceleration (RMSacc) at the head and pelvis was used. [Results] The results show that the body stability of young adults showed a similar RMSacc in all directions at the head and pelvis between the normal and low light walking conditions. In contrast, the RMSacc in all directions at the head and pelvis during low light walking by elderly adults was significantly greater than that of normal light walking. [Conclusion] It was confirmed that, despite walking on even ground, low light condition affects the body stability of the elderly. To clearly evaluate the effect of low light with aging on gait pattern, further study will be necessary to perform additional experiments under various environmental conditions to investigate walking speed, multi-tasking, stairs, and uneven walkway performance.

Parameters of gait among community-dwelling older adults

BACKGROUND

Functional fitness is the ability of an older adult to perform activities of daily living. Stair-climb power is a well-documented marker of functional fitness among older adults. Gait velocity and parameters of gait are related to functional fitness but have been understudied to date.

PURPOSE

The purpose of this observational study was to determine differences in parameters of gait between high- and low-functioning older adults.

METHODS

Twenty high-functioning older adults, mean age (SD)=71.6 (5.6), volunteered for the cross-sectional observational study. Functional fitness was determined by a stair-climb performance test. Parameters of gait included velocity, step length, swing and stance phase, double support time, ground reaction forces, impulse, and propulsion during habitual walking. Analysis of variance was performed to determine differences in the dependent variables between groups.

RESULTS

Individuals with high levels of functional fitness walked 13.1% faster than the lower-functioning group (P=.01). No significant differences (P>.05) were detected for any other measure; however, all gait parameters were more favorable in the higher-functioning group.

CONCLUSION

Functional fitness is imperative for older adults as declines could hinder mobility. Thus, earlier detection of declines in gait parameters may reduce the risk of falling. The results suggest that gait velocity was slower among older adults with lower levels of functional fitness.

Instrumenting gait with an accelerometer: a system and algorithm examination

Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required.

Temporo-spatial gait parameters during street crossing conditions: a comparison between younger and older adults

Most traffic accidents involving pedestrians happen during street crossing. Safe street crossing by older adults requires complex planning and imposes high cognitive demands. Understanding how street crossing situations affect younger and older adults' gait is important to create evidence-based policies, education and training. The objective of this study was to develop and test a method to evaluate temporo-spatial gait parameters of younger and older adults during simulated street crossing situations. Twenty-two younger (25±2 years old) and 22 older adults (73±6 years old) who lived independently in the community completed 3 walking trials at preferred gait speed and during simulated street crossing with regular and with reduced time. There were significant differences between groups (p<0.001) and conditions (p<0.001). Older adults' street crossing walking speed was higher than their preferred speed (p<0.001). Gait during simulated street crossing resulted in significant and progressive gait changes. The methods developed and tested can be used to (1) evaluate if people are at risk of falls and accidents during street crossing situations, (2) to compare among different groups, and (3) to help establish appropriate times for older pedestrians to cross streets safely. The current time to cross streets is too short even for healthy older adults.

Labral reconstruction with iliotibial band autografts and semitendinosus allografts improves hip joint contact area and contact pressure: an in vitro analysis

BACKGROUND

Labral reconstruction using iliotibial band (ITB) autografts and semitendinosus (Semi-T) allografts has recently been described in cases of labral deficiency.

PURPOSE/HYPOTHESIS

To characterize the joint biomechanics with a labrum-intact, labrum-deficient, and labrum-reconstructed acetabulum in a hip cadaveric model. The hypothesis was that labral resection would decrease contact area, increase contact pressure, and increase peak force, while subsequent labral reconstruction with ITB autografts or Semi-T allografts would restore these values toward the native intact labral state.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten fresh-frozen human cadaveric hips were analyzed utilizing thin-film piezoresistive load sensors to measure contact area, contact pressure, and peak force (1) with the native intact labrum, (2) after segmental labral resection, and (3) after graft labral reconstruction with either ITB autografts or Semi-T allografts. Each specimen was examined at 20° of extension and 60° of flexion. Statistical analysis was conducted through 1-way analysis of variance with post hoc Games-Howell tests.

RESULTS

For the ITB group, labral resection significantly decreased contact area (at 20°: 73.2%±5.38%, P=.0010; at 60°: 78.5%±6.93%, P=.0063) and increased contact pressure (at 20°: 106.7%±4.15%, P=.0387; at 60°: 103.9%±1.15%, P=.0428). In addition, ITB reconstruction improved contact area (at 20°: 87.2%±12.3%, P=.0130; at 60°: 90.5%±8.81%, P=.0079) and contact pressure (at 20°: 98.5%±5.71%, P=.0476; at 60°: 96.6%±1.13%, P=.0056) from the resected state. Contact pressure at 60° of flexion was significantly lower compared with the native labrum (P=.0420). For the Semi-T group, labral resection significantly decreased contact area (at 20°: 68.1%±12.57%, P=.0002; at 60°: 67.5%±6.70%, P=.0002) and increased contact pressure (at 20°: 105.3%±3.73%, P=.0304; at 60°: 106.8%±4.04%, P=.0231). Semi-T reconstruction improved contact area (at 20°: 87.9%±7.95%, P=.0087; at 60°: 92.9%±13.2%, P=.0014) and contact pressure (at 20°: 97.1%±3.18%, P=.0017; at 60°: 97.4%±4.39%, P=.0027) from the resected state. Comparative analysis demonstrated no statistically significant differences between either graft reconstruction in relation to contact area, contact pressure, or peak force.

CONCLUSION

Segmental anterosuperior labral resection results in significantly decreased contact areas and increased contact pressures, while labral reconstruction partially restores time-zero acetabular contact areas and pressures as compared with the resected state. Although labral reconstruction improved the measured biomechanical properties as compared with the resected state, some of these properties remained significantly different compared with the native intact labrum.

CLINICAL RELEVANCE

Labral reconstruction appears to improve femoroacetabular joint biomechanics as compared with the labrum-resected state; these improved biomechanics may translate into increased joint function clinically.

Gait and foot clearance parameters obtained using shoe-worn inertial sensors in a large-population sample of older adults

In order to distinguish dysfunctional gait, clinicians require a measure of reference gait parameters for each population. This study provided normative values for widely used parameters in more than 1,400 able-bodied adults over the age of 65. We also measured the foot clearance parameters (i.e., height of the foot above ground during swing phase) that are crucial to understand the complex relationship between gait and falls as well as obstacle negotiation strategies. We used a shoe-worn inertial sensor on each foot and previously validated algorithms to extract the gait parameters during 20 m walking trials in a corridor at a self-selected pace. We investigated the difference of the gait parameters between male and female participants by considering the effect of age and height factors. Besides; we examined the inter-relation of the clearance parameters with the gait speed. The sample size and breadth of gait parameters provided in this study offer a unique reference resource for the researchers.

A comparison of gait characteristics in the elderly people, people with knee pain, and people who are walker dependent people

[Purpose] The purpose of this study was to compare the gait parameters of age-matched people with a normal gait (≥ 65 years), age-matched people with knee pain, and age-matched people with walker dependent gait at a self-selected gait speed. [Methods] Subjects walked on even ground in bare feet and were allowed a natural arm swing on a 6-m walkway. Walker-dependent participants walked on a walkway without a walker. [Results] The kinematic and spatiotemporal gait characteristics were used to investigate the difference among the each group. Hip flexion, knee flexion, and stride width parameters were not different. The gait speed, stride length and time, hip and knee extension, and ankle flexion and extension parameters were significantly different. [Conclusion] A comparision of kinematic and spatiotemporal gait characteristics during gait may provide an insight into the gait pattern of normal elderly people, those with knee pain, and the walker-dependent elderly.

Tracking of Markers for 2D and 3D Gait Analysis Using Home Video Cameras

This work presents the development of an affordable optical motion-capture system which uses home video cameras for 2D and 3D gait analysis. The 2D gait analyzer system consists of one camcorder and one PC while the 3D gait analyzer system uses two camcorders, a flash and two PCs. Both systems make use of 25 fps camcorder, LED markers and technical computing software to track motions of markers attached to human body during walking. In the experiment for 3D gait analyzer system, the two cameras are synchronized by using flash. The recorded videos for both systems are extracted into frames and then converted into binary images, and bridge morphological operation is applied for unconnected pixel to facilitate marker detection process. Least distance method is then employed to track the markers motions, and 3D Direct Linear Transformation is used to reconstruct 3D markers positions. The correlation between length in pixel and in the real world resulted from calibration process is used to reconstruct 2D markers positions. To evaluate the reliability of the 2D and 3D optical motion-capture system developed in the present work, spatio-temporal and kinematics parameters calculated from the obtained markers positions are qualitatively compared with the ones from literature, and the results show good compatibility.

The biomechanical mechanism of how strength and power training improves walking speed in old adults remains unknown

Maintaining and increasing walking speed in old age is clinically important because this activity of daily living predicts functional and clinical state. We reviewed evidence for the biomechanical mechanisms of how strength and power training increase gait speed in old adults. A systematic search yielded only four studies that reported changes in selected gait biomechanical variables after an intervention. A secondary analysis of 20 studies revealed an association of r(2)=0.21 between the 22% and 12% increase, respectively, in quadriceps strength and gait velocity in 815 individuals age 72. In 6 studies, there was a correlation of r(2)=0.16 between the 19% and 9% gains in plantarflexion strength and gait speed in 240 old volunteers age 75. In 8 studies, there was zero association between the 35% and 13% gains in leg mechanical power and gait speed in 150 old adults age 73. To increase the efficacy of intervention studies designed to improve gait speed and other critical mobility functions in old adults, there is a need for a paradigm shift from conventional (clinical) outcome assessments to more sophisticated biomechanical analyses that examine joint kinematics, kinetics, energetics, muscle-tendon function, and musculoskeletal modeling before and after interventions.

Analysis of Balance Ability Dependent on the Angle of the Knee Joint in Females in Their 20s

The aim of this study was to investigate how balance ability according to angle of the knee joint changes in young female adults wearing a knee orthosis. [Methods] This study was conducted with 11 healthy female adults. The subjects used a knee brace that could be set to angles of 0°, 15°, and 30° of knee flexion. The ability to balance was evaluated by balance assessment. A total of four postures were used for measurements: a forward-facing posture with the eyes open on a stable surface (NO), a forward-facing posture with the eyes closed on a stable surface (NC), a forward-facing posture with the eyes open on an unstable surface (PO), and a forward-facing posture with the eyes closed on an unstable surface (PC). [Results] Regarding the weight distribution index and stability index on a stable surface, there was no interaction according to whether there was visual deprivation or not or according to knee flexion angle. Furthermore, the stability index on an unstable surface showed no interaction according to whether there was visual deprivation or not or according to knee flexion angle. But the WDI on a stable surface showed no interaction according to whether there was visual deprivation or not or according to knee flexion angle. [Conclusion] There were significant differences in the knee extension range of motion of normal elderly people and knee osteoarthritis, and the quadriceps femoris played an important role in knee function in individuals with knee osteoarthritis.

Multisegment foot kinematics during walking in younger and older adults

Background

Currently, age-related changes in foot mechanics are poorly understood. A greater understanding of the natural changes in foot motion is needed to improve our understanding of pathological foot conditions.

Methods

The purpose of this study was to compare multisegment foot kinematic data during gait in younger and older individuals. Eleven (N = 11) adult male participants between the ages of 18 - 30 years (younger group; mean ± SD: 24.6 ± 3.0 years) and eleven (N = 11) adults aged 55 years or older (older group; mean ± SD: 65.0 ± 4.2 years) were recruited for the study. The foot was modeled as a four-segment rigid body model. Three-dimensional kinematic and kinetic gait parameters were recorded using an 8-camera Vicon MCam motion capture system and two Kistler force plates. A MANOVA was used to test for significant differences in mean temporal-spatial data, mean ranges of motion, and mean peak joint angle data between age groups.

Results

No significant differences (P > 0.05) were found between the two age groups for any of the gait parameters. The results of the present study suggest that individuals aged 65.0 ± 4.2 years have foot mechanics that are comparable to younger walkers.

Conclusions

As such, any deviations in motion at this age may be indicative of an underlying disease or disorder.