Minimum Foot Research Articles

A Scoping Review on Minimum Foot Clearance Measurement: Sensing Modalities.

Background: Falls are a major public health issue and tripping is the most common self-reported cause of outdoor falls. Minimum foot clearance (MFC) is a key parameter for identifying the probability of tripping. Optical motion capture systems are commonly used to measure MFC values; however, there is a need to identify alternative modalities that are better suited to collecting data in real-world settings. Objective: This is the first of a two-part scoping review. The objective of this paper is to identify and evaluate alternative measurement modalities to optical motion capture systems for measuring level-ground MFC. A companion paper identifies conditions that impact MFC and the range of MFC values individuals that these conditions exhibit. Methods: We searched four electronic databases, where peer-reviewed journals and conference papers reporting level-ground MFC characteristics were identified. The papers were screened by two independent reviewers for inclusion. The reporting was done in keeping with the PRISMA-ScR reporting guidelines. Results: From an initial search of 1571 papers, 17 papers were included in this paper. The identified technologies were inertial measurement units (IMUs) (n = 10), ultrasonic sensors (n = 2), infrared sensors (IR) (n = 2), optical proximity sensors (OPS) (n = 1), laser ranging sensors (n = 1), and ultra-wideband sensors (n = 1). From the papers, we extracted the sensor type, the analysis methods, the properties of the proposed system, and its accuracy and validation methods. Conclusions: The two most commonly used alternative modalities were IMUs and OPS. There was a lack of standardization among studies utilizing the same measurement modalities, as well as discrepancies in the methods used to assess performance. We provide a list of recommendations for future work to allow for more meaningful comparison between modalities as well as future research directions.

A Scoping Review on Minimum Foot Clearance: An Exploration of Level-Ground Clearance in Individuals with Abnormal Gait.

Background: Falls are a major health concern, with one in three adults over the age of 65 falling each year. A key gait parameter that is indicative of tripping is minimum foot clearance (MFC), which occurs during the mid-swing phase of gait. This is the second of a two-part scoping review on MFC literature. The aim of this paper is to identify vulnerable populations and conditions that impact MFC mean or median relative to controls. This information will inform future design/maintenance standards and outdoor built environment guidelines. Methods: Four electronic databases were searched to identify journal articles and conference papers that report level-ground MFC characteristics. Two independent reviewers screened papers for inclusion. Results: Out of 1571 papers, 43 relevant papers were included in this review. Twenty-eight conditions have been studied for effects on MFC. Eleven of the 28 conditions led to a decrease in mean or median MFC including dual-task walking in older adults, fallers with multiple sclerosis, and treadmill walking. All studies were conducted indoors. Conclusions: The lack of standardized research methods and covariates such as gait speed made it difficult to compare MFC values between studies for the purpose of defining design and maintenance standards for the outdoor built environment. Standardized methods for defining MFC and an emphasis on outdoor trials are needed in future studies.

A shoe-insole to improve ankle joint mechanics for injury prevention among older adults

Technologies to assist senior individuals with active walking are important. This experiment aimed to investigate whether a customised insole geometry would reduce the risk of falls and locomotive injuries. The tested insole incorporated a built-in inclination to assist ankle dorsiflexion (2.2°) and eversion (4.5°). Twenty-six older adults and 30 younger counterparts undertook gait assessment with and without the experimental insole while 3 D motion capture and force plates recorded gait. The insole increased swing foot-ground clearance, with.43 cm for the older adults' dominant foot. The insole also prevented excessive lateral centre of pressure movement. The main insole effects on foot contact mechanics were (i) prolonged time to foot-flat (.015 s) and (ii) improved energy efficiency (2%). Reduced knee adduction moment (>15%) was observed in the older group. Shoe insoles to provide dorsiflexion and eversion support may have the potential to reduce the risk of falls and locomotion-related injuries for older adults. Practitioner Summary: Using 3 D gait assessment techniques this research investigated shoe-insoles incorporating ankle dorsiflexion and eversion support features. It was shown that falls risk and locomotive injuries could be reduced by the application of orthotics to support ankle dorsiflexion and eversion. Shoe-orthotics may provide practical low-cost solutions to correcting gait impairments. Abbreviations: MFC: minimum foot clearance; CoP: centre of pressure; OA: osteoarthritis; GRF: ground reaction forces; IREDS: infra-red light emitting diodes; PE: potential energy; KE: kinetic energy; IQR: interquartile range; ANOVA: analysis of variance

Risk of tripping, minimum foot clearance, and step length when crossing a barrier

This study was designed to investigate gait parameters upon crossing a barrier and environmental factors influencing the perceived risk of tripping. These factors included illumination and barrier conditions. Barrier conditions were divided into height, type, and color of the barrier. Illumination conditions included normal and dimmed conditions. Twelve male participants were recruited. They walked on a walkway, moving over a barrier. They gave a subjective rating of risk of tripping (SRRT) both before and after the walk. A research assistant recorded a gait disturbance rating (GDR) of the participant upon barrier crossing. The minimum foot clearance (MFC) of both the leading and lagging foot when moving over the barrier, and the step length of the participant before and after crossing the barrier were calculated. The results indicated that the SRRT, both before and after the walk, was significantly (p < 0.0001) higher when the barrier height increased. Increased barrier height caused significantly (p < 0.0001) higher GDR. The barrier type (p < 0.01) and illumination conditions (p < 0.001) had significant effects on the MFC of both the leading and the lagging foot. The color (p < 0.05) and height (p < 0.05) of the barrier also influenced the MFC of the lagging foot significantly. Step length of the leading foot when crossing the barrier was significantly affected by illumination condition (p < 0.001) and barrier type (p < 0.05). The results of the study are helpful in understanding the mechanisms brought into play when moving over barriers on walkways. They provide meaningful information that will help in reducing trip and fall accidents.

Development of an Automated Minimum Foot Clearance Measurement System: Proof of Principle.

Over half of older adult falls are caused by tripping. Many of these trips are likely due to obstacles present on walkways that put older adults or other individuals with low foot clearance at risk. Yet, Minimum Foot Clearance (MFC) values have not been measured in real-world settings and existing methods make it difficult to do so. In this paper, we present the Minimum Foot Clearance Estimation (MFCE) system that includes a device for collecting calibrated video data from pedestrians on outdoor walkways and a computer vision algorithm for estimating MFC values for these individuals. This system is designed to be positioned at ground level next to a walkway to efficiently collect sagittal plane videos of many pedestrians’ feet, which is then processed offline to obtain MFC estimates. Five-hundred frames of video data collected from 50 different pedestrians was used to train (370 frames) and test (130 frames) a convolutional neural network. Finally, data from 10 pedestrians was analyzed manually by three raters and compared to the results of the network. The footwear detection network had an Intersection over Union of 85% and was able to find the bottom of a segmented shoe with a 3-pixel average error. Root Mean Squared (RMS) errors for the manual and automated methods for estimating MFC values were 2.32 mm, and 3.70 mm, respectively. Future work will compare the accuracy of the MFCE system to a gold standard motion capture system and the system will be used to estimate the distribution of MFC values for the population.

Feasibility of Using Foot-Ground Clearance Biofeedback Training in Treadmill Walking for Post-Stroke Gait Rehabilitation.

Hemiplegic stroke often impairs gait and increases falls risk during rehabilitation. Tripping is the leading cause of falls, but the risk can be reduced by increasing vertical swing foot clearance, particularly at the mid-swing phase event, minimum foot clearance (MFC). Based on previous reports, real-time biofeedback training may increase MFC. Six post-stroke individuals undertook eight biofeedback training sessions over a month, in which an infrared marker attached to the front part of the shoe was tracked in real-time, showing vertical swing foot motion on a monitor installed in front of the subject during treadmill walking. A target increased MFC range was determined, and participants were instructed to control their MFC within the safe range. Gait assessment was conducted three times: Baseline, Post-training and one month from the final biofeedback training session. In addition to MFC, step length, step width, double support time and foot contact angle were measured. After biofeedback training, increased MFC with a trend of reduced step-to-step variability was observed. Correlation analysis revealed that MFC height of the unaffected limb had interlinks with step length and ankle angle. In contrast, for the affected limb, step width variability and MFC height were positively correlated. The current pilot-study suggested that biofeedback gait training may reduce tripping falls for post-stroke individuals.

A solution method for predictive simulations in a stochastic environment

Predictive gait simulations currently do not account for environmental or internal noise. We describe a method to solve predictive simulations of human movements in a stochastic environment using a collocation method. The optimization is performed over multiple noisy episodes of the trajectory, instead of a single episode in a deterministic environment. Each episode used the same control parameters. The method was verified on a torque-driven pendulum swing-up problem. A different optimal trajectory was found in a stochastic environment than in the deterministic environment. Next, it was applied to gait to show its application in predictive simulation of human movement. We show that, unlike in a deterministic model, a nonzero minimum foot clearance during swing is predicted by a minimum-effort criterion in a stochastic environment. The predicted amount of foot clearance increased with the noise amplitude.

A study of the ultra-short T-shaped gate profile controlled by the sensitivity difference in bilayer resists

InP based InGaAs/InAlAs high electron mobility transistors (HEMTs) are advancing toward upper terahertz (THz) frequency beyond 500 GHz, driven by the constant shrinkage of the foot width in T-shaped gates. However, when the foot width is reduced to 30 nm, the dc and/or rf performance of HEMTs is strongly related to the foot profile of the T-shaped gates. Conventional method is to utilize proximity effect correction (PEC) to control the gate profile within a specific bilayer. To obtain the optimized bilayer for the desired T-shaped profiles, another parameter, that is the sensitivity ratio of the top layer over the bottom one should play the decisive role, which has never been addressed so far. This work focuses on the control of T-shaped gate profile by utilizing the difference in the sensitivities between the bottom and the top layer both theoretically and experimentally. The minimum foot width achievable for a particular bilayer is worked out in almost the whole range of the sensitivity ratio from 3:1 to 37:1. By accurately controlling the influence of sensitivity ratio on the profile of T-shaped gate and the minimum foot width, the specific gate structure desired can be precisely prepared to meet the performance requirements of the device.

Development and implementation of a theoretical-practical program to standardize the training of Brazilian foot and ankle surgeon

Objective: 1) to identify characteristics of the functioning and production of training centers responsible for the training of foot and ankle specialists in Brazil; 2) establish minimum quality criteria to provide adequate professional training of the foot and ankle specialist; 3) create a baseline to endorse the minimum foot and ankle specialist training program; 4) to rank, in terms of qualification and efficiency, the training centers of specialists in the area of ​​foot and ankle. Methods: protocol containing information provided by physicians responsible for 31 accredited national services as centers for training foot and ankle specialists at ABTPé in the 2012-2015 quadrennium. Results: minimum operating and production criteria were established based on the information collected. We identified that: 1) it was possible to establish criteria for a possible standardization in the training programs, both in the theoretical and practical field; 2) the relevant scientific output of the training centers is still low and should be stimulated to increase both quantity and quality; 3) the academic qualification of physicians responsible for training specialists is low; 4) The classification of training centers according to hierarchical quality criteria can be established by objective criteria. Conclusion: Quality goals, with objective and well-defined criteria, could be established allowing standardizing the type of training offered to training specialists distributed throughout the national territory, making it more uniform. The evaluation criteria adopted also allowed to establish a hierarchical classification of training centers in the area of ​​foot and ankle, creating a reference base to qualify the training offered in these institutions.

129 Effects of Physical Capacity, Executive Function, Mental Health and Polypharmacy on Gait and Falls Risks among Older Adults

Abstract Falls prevention is an important healthcare topic in an ageing society due to serious and costly injuries. Gait biomechanics utilising 3D motion capture system can possibly identify fall-prone walking patterns. It is, therefore, important to reveal factors for negative gait changes and higher falls risks. A total of 54 community-dwelling senior citizens undertook a series of examinations: (i) fundamental gait assessment - step length, step width, double support time; (ii) the risk of tripping falls - minimum foot clearance (MFC); (iii) flat-foot contact - foot contact angle; (iv) fundamental physical tests - grip strength, functional reach, one-leg standing; (v) executive function - trail making test-A; (vi) Psychological health - General Health Questionnaire 12; (vii) falls history and (viii) polypharmacy. Pearson’s correlations were computed between gait data and the other potentially related factors. A reduced number of drugs (r = -.353, p &amp;lt; .01) and prolonged one-leg standing i.e. improved balance (r =.333, p &amp;lt; .05) demonstrated interlinks with greater step length, indicating the overall gait health. Step length was also strongly correlated with foot contact angle (r = .537, p &amp;lt; .01), which was further associated with one leg standing (r = .339, &amp;lt; .05). The risk of tripping (MFC) showed interrelations with one leg standing (r = .273, &amp;lt; .05) and functional reach (r = .289, &amp;lt; .05). Furthermore, step width was also correlated with one leg standing (r = -.289, &amp;lt; .05) and functional reach (r = -.278, &amp;lt; .05). Balance control capacity (one leg standing) and flexibility (functional reach) may be, therefore, closely related to gait control and tripping risks. While fundamental physical tests thus adequately reflected gait data, mental health and executive function were not correlated with gait data in the current study. Further investigation with a larger sample size will be required.

05 Shoe Insole Intervention to Reduce Falls and Injuries

Abstract Despite a number of strategies to minimise falls risks, older adults tend to avoid voluntary and continuous engagement into interventions without cost effectiveness and simplicity. Shoe-insole modification may be a practical intervention if it alters foot geometry inside a shoe and improves gait patterns to prevent falls. The current study designed a shoe-insole structure with 2.2 dorsiflexion and 4.5 eversion built-in inclinations on the entire insole surface. Ankle dorsiflexion is fundamental for higher swing foot clearance to reduce tripping falls. Eversion support may also regulate excessive lateral foot centre of pressure (CoP) excursion to prevent ankle sprain and associated falls. Three young male participants (Age: 21 ± 3 yrs., Height: 1.70 ±.08m, Body Mass: 65.3 ± 2.65kg) conducted gait testing on an 8m walkway repeatedly to collect 60 step cycles for both non-insole and insole conditions. Optotrak motion capture system (NDI) recorded swing foot clearance at 100 Hz while AMTI force plates obtained ground reaction forces data, therefore CoP movements. Minimum foot clearance (MFC) was defined as the local minimum vertical toe-ground clearance during mid-swing, where higher MFC prevents tripping falls. The tested insole increased MFC by .20cm on average, considered to effectively reduce tripping falls. Lateral CoP excursion (lateral displacement from initial CoP location at heel contact to the most lateral CoP location during the initial phase of loading response) was reduced by 1.18cm (61%) due to insole walking, possibly indicating the lower risk of ankle sprain and sideways balance loss. Despite these positive effects, further validation is necessary with a sufficient sample size including the older population. It is also essential to consider negative aspects of continuous dorsiflexion and eversion support. For example, the tested insole may disturb functionally important supination. Prior to practical use, human trials for a prolonged period of time are required for insole intervention.

Maintaining stable transtibial amputee gait on level and simulated uneven conditions in a virtual environment

Purpose This research compares gait strategies to maintain stable gait over a variety of non-level walking conditions for individuals with a transtibial amputation and able-bodied individuals. Methods Twelve people with unilateral transtibial amputation and twelve able-bodied individuals walked on a self-paced treadmill in a park-like virtual environment with level and continuous perturbation conditions. Walking stability was quantified by margin-of-stability, step parameters (walking speed, temporal and spatial parameters, and foot clearance), and gait variability (standard deviations for margin-of-stability, step parameters, and root-mean-square of trunk acceleration). Results and conclusions For non-level conditions, able-bodied and transtibial groups had greater root-mean-square of trunk acceleration and walked with a cautious and variable step strategy by changing speed, step width, foot clearance, margin-of-stability, and increasing step variability. Overall, able-bodied and transtibial amputee participants adopted similar strategies to maintain stable gait over non-level conditions, but the amputee group was more variable than the able-bodied group. These results demonstrated the importance of measuring gait variability, including trunk acceleration and step variability measures, when quantitatively assessing mobility for individuals with a transtibial amputation. Implications for rehabilitation Able-bodied and transtibial amputee groups adapted gait biomechanics for simulated uneven conditions. Adaptations for non-level conditions included increasing step width, margin-of stability, minimum foot clearance, and varying speed. Gait was also more variable for non-level conditions, with greater variability for transtibial amputee participants compared to able-bodied participants. These results highlight the importance of measuring variability when performing comprehensive walking assessment, particularly for active individuals who achieve maximal performance on standard assessments yet report functional limitations in daily living.

Foot-ground clearance characteristics in women: A comparison across different ages

BackgroundTripping is a common event leading to falls amongst elderly. Minimum foot clearance (MFC) is a critical swing phase control factor associated with tripping and falls. Research questionAre there differences in MFC characteristics among three age groups of women and are there association between MFC and lower limb kinematics? MethodsCross-sectional observational study. Three-dimensional gait analysis of 55 healthy women. ANOVA was used to compare (p<0.05) MFC characteristics among young, middle-aged and elderly groups. Multiple Linear Regression Analysis was used to test prediction over MFC. ResultsElderly women walked slower, with lower MFC and lower maximum foot velocity during swing (MFV) than young and middle-aged women. There were more hip flexion and less ankle dorsiflexion during MFC among elderly. There is a strong positive relationship between dorsiflexion and MFC. And ankle dorsiflexion was the most predictive variable over MFC. SignificanceElderly women walk slower with lower MFC value and less ankle dorsiflexion than gender-matched young controls. Increased hip flexion may represent a gait adaptation to avoid tripping. Gait speed had no effect on those findings.

Decreasing the Risk of Fall by Non-Actuated Walking Assist Device for Elderly

The gait ability of the elderly decreases and the risk of fall increases. Thus, we developed wearable assist devices which improved dorsal flexion and minimum foot clearance (MFC) of the elderly. This device uses upper body muscle as a power source instead of an actuator. Attached strings transfer muscle power from the upper body to foot for assisting walking. To improve the efficiency of assist pattern, string paths were optimized through joint torque simulation. This simulator made three optimal paths which apply dorsal flexion torque. As a result of walking experiments, one of three optimal paths improved elderly MFC.

Shannon Logic Based Novel QCA Full Adder Design with Energy Dissipation Analysis

Quantum-dot Cellular Automata (QCA) is an emerging nanotechnology to replace VLSI-CMOS digital circuits. Due to its attractive features such as low power consumption, ultra-high speed switching, high device density, several digital arithmetic circuits have been proposed. Adder circuit is the most prominent component used for arithmetic operations. All other arithmetic operation can be successively performed using adder circuits. This paper presents Shannon logic based QCA efficient full adder circuit for arithmetic operations. Shannon logic expression with control variables helps the designer to reduce hardware cost; using with minimum foot prints of the chip size. The mathematical models of the proposed adder are verified with the theoretical values. In addition, the energy dissipation losses of the proposed adder are carried out. The energy dissipation calculation is evaluated under the three separate tunneling energy levels, at temperature T = 2K.The proposed adder dissipates less power. QCAPro tool is used for estimating the energy dissipation. In this paper we proposed novel Shannon based adder for arithmetic calculations. This adder has been verified in different aspects like using Boolean algebra besides it power analysis has been calculated. In addition 1-bit full adder has been enhanced to propose 2-bit and 4-bit adder circuits.

Long-term Tai Chi practitioners have superior body stability under dual task condition during stair ascent

BackgroundStair walking contributed to 26% of self-reported falls and become the leading cause of accidental death for the elderly. The risk of fall increases while performing a cognitive task, like talking and/or reasoning. Research questionOur work aimed to found out whether body stability under physical-cognitive dual task(DT) condition during stair ascent is superior among long-term Tai Chi (TC) practitioners. MethodsFifteen healthy, elderly long-term TC practitioners and fifteen no exercise(NE) practitioners were asked to walking ascent the stairs under single task(ST) and DT conditions in this cross-sectional study. Vicon motion analysis system and Kistler force plates were used synchronously to collect data. Ninety-five% confidence intervals, effect size and statistical power were calculated for each dependent variable to confirm significant difference. ResultsCompared with NE practitioners, TC practitioners had a lower head inclination angle, trunk inclination angle, hip angle, laterial impulse and center of mass-center of pressure(COM-COP)ap/ml separation, a higher ankle angle and loading rate under DT condition; TC practitioners had a lower head inclination angle, trunk inclination angle, higher ankle angle, loading rate and COM-COPml separation under ST condition. Compared with under ST condition, TC practitioners increased in minimum foot clearance, NE practitioners increased in laterial impulse and COM-COPml separation under DT condition. Under DT condition, body stability decreased among NE practitioners, while TC practitioners remained unchanged. SignificanceAt present, there is no drug therapy proven to delay preclinical cognitive deterioration, it would be great helpful for the elderly if TC was been proved to improve their performance under cognitive related conditions.

Nitrogen and Water Use Efficiency in Conservation Agriculture

Conservation agriculture is resource conserving strategy for improving productivity and profitability of farming through efficient utilization of available resources with minimum foot print to the environment. Conservation Agriculture helps in carbon sequestration, soil erosion control, ground water recharge and moisture conservation. Conservation agriculture has been found to improve physical, chemical and biological properties of soil compared to conventional practices and ultimately helps in increasing nutrient and water use efficiency. Optimizing soil fertility and soil moisture simultaneously is possible through CA practice which ultimately increases resource use efficiency.Int. J. Appl. Sci. Biotechnol. Vol 6(2): 63-66

Relationship between regional neuromuscular regulation within human rectus femoris muscle and lower extremity kinematics during gait in elderly men

Biomechanical and neurophysiological mechanisms of age-related gait dysfunction have not been fully understood. We aimed to investigate the relationship between region-specific electromyography (EMG) response of the rectus femoris (RF) muscle and lower extremity kinematics during swing phase of gait for the elderly. For thirteen elderly men (age: mean 71.3 years, standard deviation 5.7 years), multi-channel surface EMG from the proximal to distal regions of the RF muscle and lower extremity kinematics were measured during normal gait on a treadmill. At minimum foot clearance during swing phase, relationship between central locus activation (CLA), which is indicator of spatial distribution of surface EMG along the RF muscle and lower joint kinematics were calculated. No significant correlations were found between CLA and any joint angle (p > 0.05). The results of our study suggested that regional neuromuscular activation of the RF muscle is not associated to lower extremity joint movements and toe clearance strategy during gait in the elderly.

Impacts of using a head-worn display on gait performance during level walking and obstacle crossing

Use of a head-worn display (HWD) may affect gait performance and increase slip and trip risks, though there is a lack of information on such effects. This study investigated how different display technologies (monocular and binocular HWDs, and a paper list) and visual information presentation modes affect gait performance. Twelve gender-balanced participants completed walking and obstacle crossing trials on a linear walking track under all experimental conditions and a baseline control (without using a technology). During these trials, information relevant to a simulated light assembly task was provided, as representative of a potential occupational application. Gait performance was assessed based on minimum foot clearance (MFC), required coefficient of friction, foot placement locations around the obstacle, and/or walking/obstacle crossing speed. Use of a HWD had no substantial effects on level walking performance. A more conservative/cautious obstacle crossing strategy was, however, observed with HWD use, including a decrease (∼3%) in obstacle crossing speed (compared to the baseline). Gender-specific foot control strategies (lead foot MFC) were also observed that depended on the specific display technology and information modes. Foot placements around the obstacle were not influenced by use of the binocular HWD, yet a conservative strategy was observed with the monocular HWD.

Body-foot geometries as revealed by perturbed obstacle position with different time constraints.

This study examined the geometrical relationships between the feet, pelvis and an environmental obstruction when crossing an obstacle with unexpected changes to its position. Nine healthy young adults stepped over an obstacle 19cm high with their right leg leading. The obstacle could be static or advanced at either lead (early detection) or trail (late detection) foot contact prior to clearance to force an adaptive reorganization of body-foot geometry and foot proximity to the obstacle. Stride length, minimum foot clearance over the obstacle, and foot-obstacle horizontal proximity before and after clearance were measured along with the relative position of the pelvis to each foot at eight points (four for each foot) during approach and clearance: heel contacts before and after crossing the obstacle, maximum foot heights and foot clearances. With early obstacle movement, trail limb stride length before crossing was lengthened, but foot proximity was still far from the final obstacle position. Clearance was less affected for the trail foot as compared to the lead foot. Proximity of the lead limb following clearance was the same for both early and late perturbations and closer than for the static obstacle condition. For relative body-foot positioning, significant differences were found only in the anterior-posterior direction. Following obstacle displacement, body-foot geometry was initially adapted, but then re-established to static obstacle values with an apparent focus on a balance geometry with the forward placed foot establishing new contact. These findings support an overall balance geometry that can be temporarily adjusted and coordinated with foot proximity to the obstruction to maintain continual gait and safe clearance.