Changes in Baropodometric Evaluation and Discomfort during the Workday in Assembly-Line Workers

Prolonged standing at work is associated with health risks. The appearance of lower-limb and lower-back discomfort is one of the most prevalent factors in prolonged standing workers. The aim of this research was to evaluate the effect of an eight-hour workday on foot pressure and musculoskeletal discomfort in standing workers. Thirty-six assembly-line workers (six women) were recruited to participate in a cross-sectional study to assess foot pressure and surface, foot, knee, and lower-back discomfort before and after a real workday. Baropodometry outcomes (surface and pressure) were evaluated by the pressure platform SensorMedica and musculoskeletal discomfort was evaluated by Cornell's Musculoskeletal Discomfort Questionaire. Total foot surface (p = 0.01) and foot discomfort (p = 0.03) increased significantly at the end of the workday. Prolonged standing during 8 h workday increased the foot discomfort and total foot surface in assembly-line workers. No foot pressure variable (forefoot, rearfoot, or total) was significantly modified after the workday in assembly-line workers.

Laser-light cueing shoes with integrated foot pressure and inertial sensing for investigating the impact of visual cueing on gait characteristics in Parkinson's disease individuals

Gait disorders are a fundamental challenge in Parkinson's disease (PD). The use of laser-light visual cues emitted from shoes has demonstrated effective in improving freezing of gait within less restrictive environments. However, the effectiveness of shoes-based laser-light cueing may vary among individuals with PD who have different types of impairments. We introduced an innovative laser-light visual shoes system capable of producing alternating visual cues for the left and right feet through one-side cueing at a time, while simultaneously recording foot inertial data and foot pressures. The effects of this visual cueing system on gait patterns were assessed in individuals with PD, both those with well-gait and those with worse-gait. Our device successfully quantified gait characteristics, including the asymmetry in the center of pressure trajectory, in individuals with PD. Furthermore, visual cueing prolonged stride times and increased the percentage of stance phase, while concurrently reducing stride length in PD individuals with well-gait. Conversely, in PD individuals with worse-gait, visual cueing resulted in a decreased freeze index and a reduction in the proportion of intervals prone to freezing episodes. The effects of visual cueing varied between PD individuals with well-gait and those with worse-gait. Visual cueing slowed down gait in the well-gait group while it appeared to mitigate freezing episodes in worse-gait group. Future researches, including enhancements to extend the projection distance of visual cues and clinical assessments conducted in real-world settings, will help establish the clinical utility of our proposed visual cueing system.

Effect of the Dynamic Orthotic Garment on Postural Control, and Endurance in Children with Spastic Diplegic Cerebral Palsy: A Randomized Controlled Trial

Purpose

To investigate the effect of dynamic orthotic garments (Thera togs) on foot pressure distribution, postural control, and endurance in children with spastic diplegic CP.

Patients and Methods

This is a single-blind randomized controlled clinical trial involving 34 (8-10 years) with spastic diplegic CP. The control group received conventional physical therapy (CPT), whereas the study group received CPT in addition to wearing TheraTogs. We recorded foot pressure distribution, trunk control measurement scale, trunk position sense, Pediatric Berg Balance Scale (PBS), and six-minute walking distance (6MWD).

Results

Both groups showed improvement. The study group had significant improvement in foot pressure distribution (p-value 0.003, 0.001, <0.001 for forefoot, midfoot, and rearfoot mean pressures respectively, and 0.005, <0.001, and 0.005 for forefoot, midfoot, and rearfoot peak pressures respectively), Pediatric balance scale, The trunk control measurement scale, and Trunk position sense (p-value < 0.001) and six-minute walking distance (p-value 0.029). Our data suggest that adding TheraTogs to conventional physiotherapy improves foot pressure, postural control, and endurance in children with spastic diplegic cerebral palsy.

Conclusion

Both TheraTogs and conventional physical therapy corrected foot pressure distribution, trunk control, improved balance, and increased 6MWD in children with spastic diplegic CP but the improvement was more significant in TheraTogs group.

Clinical Trial Registration

NCT05271149.

Analysis of mechanical characteristics of walking and running foot functional units based on non-negative matrix factorization

Objective: To explore the characteristics of Non-Negative Matrix Factorization (NNMF) in analyzing the mechanical characteristics of foot functional units during walking and running. Methods: Eighteen subjects (9 males and 9 females) were recruited, and the ground reaction force curves of each foot region during walking and running were collected using a plantar pressure measurement system. NNMF was used to extract the mechanical features of different foot regions and to determine the number of foot functional units. The differences between the base matrices of walking and running were compared by traditional t-tests, and the differences in coefficient matrices were compared by one-dimensional statistical parameter mapping. Results: 1) When the number of foot functional units for walking and running were both 2, the Variability Accounted For (VAF) by the matrix exceeded 0.90 (VAF walk = 0.96 ± 0.02, VAF run = 0.95 ± 0.04); 2) In foot functional unit 1, both walking and running exhibited buffering function, with the heel region being the main force-bearing area and the forefoot also participating in partial buffering; 3) In foot functional unit 2, both walking and running exhibited push-off function, with the middle part of the forefoot having a higher contribution weight; 4) In foot functional unit 1, compared to walking, the overall force characteristics of the running foot were greater during the support phase of the 0%-20% stage, with the third and fourth metatarsal areas having higher contribution weights and the lateral heel area having lower weights; 5) In foot functional unit 2, compared to walking, the overall force was higher during the beginning and 11%-69% stages of running, and lower during the 4%-5% and 73%-92% stages. During running, the thumb area, the first metatarsal area and the midfoot area had higher contribution weights than during walking; in the third and fourth metatarsal areas, the contribution weights were lower during running than during walking. Conclusion: Based on the mechanical characteristics of the foot, walking and running can both be decomposed into two foot functional units: buffering and push-off. The forefoot occupies a certain weight in both buffering and push-off functions, indicating that there may be a complex foot function transformation mechanism in the transverse arch of foot. Compared to walking, running completes push-off earlier, and the force region is more inclined towards the inner side of the foot, with the hallux area having a greater weight during push-off. This study suggests that NNMF is feasible for analyzing foot mechanical characteristics.

Analysis of Static Plantar Pressures in School-Age Children with and without Functional Hallux Limitus: A Case-Control Study

BACKGROUND

The presence of hallux limitus in adulthood is frequently encountered in clinical practice, generating other biomechanical, structural, and functional compensations in dynamics secondary to blockage of the main pivot in the sagittal plane, the first metatarsophalangeal joint. In addition, the presence of functional hallux limitus (FHL) in school-age children is also increasing. Currently, there is a lack of scientific literature about this condition in the pediatric population, and early diagnosis is necessary to reduce future biomechanical disorders and avoid the development of foot arthritis. The purpose of this research was to identify static plantar pressures in school-age children with and without hallux limitus.

METHODS

A total sample of 106 children aged between six and twelve years old was divided into two groups: the case group (53 subjects with functional hallux limitus) and the control group (53 subjects without functional hallux limitus). Data were acquired with the participants in a standing barefoot position on the pressure platform, and the hallux limitus functional test was performed in a sitting position to classify the individuals into the determined study group. The variables analyzed in the research were: plantar pressure, bilateral forefoot and rearfoot surface area, bilateral forefoot and rearfoot ground reaction forces, bilateral forefoot and rearfoot distribution of body weight, total left and right surface area, maximum pressure of the left foot and right foot, medium pressure of the left foot and right foot, ground reaction forces of the left foot and right foot, and the weight of each foot.

RESULTS

Age was the only descriptive quantitative variable that showed a significant difference between the two study groups, with a p-value of 0.031. No statistically significant differences were found between groups in the bilateral forefoot and rearfoot surface area, ground reaction forces, distribution of body weight, or maximum and medium plantar pressure in the left and right foot.

CONCLUSIONS

Changes in the location of the maximum pressure were observed, particularly in older participants with FHL, but these results were not significant. The findings of this study did not show significant differences between the static plantar pressures of school-age individuals with and without functional hallux limitus.

Predicting the metabolic cost of exoskeleton-assisted squatting using foot pressure features and machine learning

Introduction: Recent studies found that wearable exoskeletons can reduce physical effort and fatigue during squatting. In particular, subject-specific assistance helped to significantly reduce physical effort, shown by reduced metabolic cost, using human-in-the-loop optimization of the exoskeleton parameters. However, measuring metabolic cost using respiratory data has limitations, such as long estimation times, presence of noise, and user discomfort. A recent study suggests that foot contact forces can address those challenges and be used as an alternative metric to the metabolic cost to personalize wearable robot assistance during walking. Methods: In this study, we propose that foot center of pressure (CoP) features can be used to estimate the metabolic cost of squatting using a machine learning method. Five subjects' foot pressure and metabolic cost data were collected as they performed squats with an ankle exoskeleton at different assistance conditions in our prior study. In this study, we extracted statistical features from the CoP squat trajectories and fed them as input to a random forest model, with the metabolic cost as the output. Results: The model predicted the metabolic cost with a mean error of 0.55 W/kg on unseen test data, with a high correlation (r = 0.89, p < 0.01) between the true and predicted cost. The features of the CoP trajectory in the medial-lateral direction of the foot (xCoP), which relate to ankle eversion-inversion, were found to be important and highly correlated with metabolic cost. Conclusion: Our findings indicate that increased ankle eversion (outward roll of the ankle), which reflects a suboptimal squatting strategy, results in higher metabolic cost. Higher ankle eversion has been linked with the etiology of chronic lower limb injuries. Hence, a CoP-based cost function in human-in-the-loop optimization could offer several advantages, such as reduced estimation time, injury risk mitigation, and better user comfort.

Lower Extremity Muscle Performance and Foot Pressure in Patients Who Have Plantar Fasciitis with and without Flat Foot Posture

Abnormal foot posture and poor muscle performance are potential causes of plantar fasciitis (PF). However, no study has compared the differences between lower extremity muscle performance and foot pressure in patients who have PF with and without abnormal foot postures. This study aimed to compare the differences in lower extremity muscle performance, such as in the hip, quadriceps, hamstring, and plantar flexor, and foot pressure in patients who have PF with and without flat foot postures. Seventy patients with plantar heel pain were enrolled (37 flat feet and 33 without flat feet). The hip muscle strength was measured using a handheld digital dynamometer. The strength and reaction time of the quadriceps, hamstring, and plantar flexor muscles were evaluated using an isokinetic device. Foot pressure parameters were assessed using pedobarography. The strength of the plantar flexor muscles was significantly lower (p = 0.008), while the reaction time of the plantar flexor muscles was significantly faster (p = 0.007) for the involved feet of PF patients with flat feet than in those without flat feet. This study confirmed the differences in muscle performance between patients who have PF with different foot postures. Therefore, clinicians and therapists should plan treatment considering the differences in these characteristics for the management of these patients.

Gait characteristics during crossing over obstacle in patients with glaucoma using insole foot pressure

BACKGROUND

Glaucoma, is the most common cause of irreversible visual deficits, presents as an injury to the optic nerve and it is mainly associated with elevated intraocular pressure. The main symptom of glaucoma is a reduction of the visual field, which is usually a source of complaint at the advanced stage of disease. Because of visual deficit, gait dysfunctions, including low gait speed and increased bumping into objects, postural sway, and falling are occurred. Many studies have used stopwatch or motion-sensing devices to report on gait function following glaucoma. However, there are few reports on gait dysfunction assessed by examining foot pressure. This study investigated gait ability following glaucoma according to different gait conditions by assessing foot pressure.

METHODS

Thirty older adults (15 in the sex- and age-matched normal group and 15 in the glaucoma group) were recruited for this study. All participants were walked under 2 different gait conditions in an F-scan system and the subject' assessments were randomly assigned to rule out the order effect. Conditions included: gait over an obstacle in a straight 6 m path, gait in a straight path without an obstacle in the 6 m path. Gait variables included cadence, gait cycle, stance time, center of force (COF) deviation, and COF excursion. About 10 minutes were taken for gait evaluation.

RESULTS

When walking without an obstacle on a 6 m path, there were significant differences between the 2 groups in gait speed, cadence, gait cycle, and stance time (P < .05). There were significant differences when walking with an obstacle on a 6 m path (P < .05). Two-way analysis of variance showed significant effects associated with "glaucoma" not gait condition on all outcomes except for COF deviation and excursion. Also, there was no the interaction effect between "glaucoma" and "gait condition."

CONCLUSION

We demonstrated that glaucoma patients selected the gait strategy such as lower gait function in both gait conditions particularly, slower gait speed and cadence and longer gait cycle and stance time, as determined by examining foot pressure. We believe that our results could help to improve the quality of life of patients with glaucoma.

Optical-Based Foot Plantar Pressure Measurement System for Potential Application in Human Postural Control Measurement and Person Identification

Plantar pressure, the pressure exerted between the sole and the supporting surface, has great potentialities in various research fields, including footwear design, biometrics, gait analysis and the assessment of patients with diabetes. This research designs an optical-based foot plantar pressure measurement system aimed for human postural control and person identification. The proposed system consists of digital cameras installed underneath an acrylic plate covered by glossy white paper and mounted with LED strips along the side of the plate. When the light is emitted from the LED stripes, it deflects the digital cameras due to the pressure exerted between the glossy white paper and the acrylic plate. In this way, the cameras generate color-coded plantar pressure images of the subject standing on the acrylic-top platform. Our proposed system performs personal identification and postural control by extracting static and dynamic features from the generated plantar pressure images. Plantar pressure images were collected from 90 individuals (40 males, 50 females) to develop and evaluate the proposed system. In posture balance evaluation, we propose the use of a posture balance index that contains both magnitude and directional information about human posture balance control. For person identification, the experimental results show that our proposed system can achieve promising results, showing an area under the receiver operating characteristic (ROC) curve of 0.98515 (98.515%), an equal error rate (EER) of 5.8687%, and efficiency of 98.515%.

The Relationship of One Leg Standing Duration to GMFM Scores and to Stance Phase of Walking in Children with Hemiplegic Cerebral Palsy

Background: Lack of stability during stance negatively impacts gait and motor function for children with unilateral cerebral palsy. Improving stability and balance are the focus for gait rehabilitation). The One-Leg-Standing-Test may give valuable information about motor function and stability of stance for patients with unilateral cerebral palsy.Objective: This study aimed to investigate the relationship between the One-Leg-Standing-Test and the gross-motor-function-measurement and single-limb support time.Methods: The study included 18 patients with unilateral cerebral palsy (age 11.08 [SD 2.84] years old). The One-Leg-Standing-Test and pedobarographic evaluation were performed. Sections D and E of the gross-motor-function-measurement were assessed, and in pedobarographic evaluation, the single-limb support time (the total duration of mid-stance and terminal-stance during walking) was calculated to describe stability during stance.Results: For patients, the One-Leg-Standing-Test scores and single-limb support time values were lower on the affected side than on the unaffected side. The One-Leg-Standing-Test was correlated with single-limb support time (p = .02, r = 0.60) and section E (p < .01, r = 0.59) values. The One-Leg-Standing-Test was also correlated to total stance phase and section D.Conclusion: The One-Leg-Standing-Test gives valuable information about gross-motor-function but cannot be substituted for motor function tests. The single-limb support time value may be used to describe stability in stance during walking.

Characteristics of physiological data during asymmetric gait of healthy subjects using a two-belt treadmill

BACKGROUND

Mobile rehabilitation systems for patients with gait disorder are being developed. Safety functions to prevent patients from falling are considered during product development; however, few studies have been conducted on systems that have been prevalidated for healthy adults prior to application to patients.

OBJECTIVE

This study analyzed the characteristics of lower extremity muscles and foot pressure in healthy adults during unbalanced walking with differences in the speed of left and right speed using a two-belt treadmill.

METHODS

Twenty subjects performed gait motions with a difference in the weight support conditions (0% and 30%) and the left and right lower limb speeds (1-3 km/h). Each subject's muscular activities and foot pressure signals were collected. The gait patterns of the faster side exhibit similar characteristics to the paralyzed leg, and the slower side is similar to the non-paralyzed leg.

RESULTS

Weight-supporting healthy subjects showed asymmetric gait patterns, similar to hemiplegic patients, because of the difference in the speed of the left and right side.

CONCLUSIONS

The quantitative results can be used to develop a training protocol for two-belt treadmills with differently controlled left and right speeds for gait rehabilitation in hemiplegic patients.

The effect of a semi-rigid thoracolumbosacral orthosis (TLSO) on foot pressure in elderly subjects presenting with spinal hyperkyphosis

Purpose: The ageing process can be accompanied by a degeneration of the spine and increase the risk of thoracic hyperkyphosis (excessive spinal forward curvature) amongst elderly people. This condition can in turn impair mobility, reduce balance, and increase the risk of falling and mortality in affected individuals. The use of corrective orthotic bracing has been shown to improve spinal posture, and increase stability and balance amongst the elderly. However, there is little evidence that evaluates the use of corrective braces on foot pressure changes in these subjects.Methods: In this study, we evaluated the use of a thoracolumbosacral orthosis (TLSO) on 19 subjects over 60 years old who presented with hyperkyphosis. We measured foot pressure using the Pedar-X system before (without brace) and after (with brace) immediate using a TLSO in both static (quite standing) and dynamic (walking on a 5 meters freeway) scenarios.Results: The results demonstrated that using a TLSO immediately decreases forefoot pressures in stasis, and around the first metatarsal, as well as pressures relating to the second to fifth metatarsals under dynamic conditions. Hindfoot pressures were increased, but not significantly.Conclusion: This study showed that using a TLSO can be beneficial for elderly people with hyperkyphosis.Implications for rehabilitationThe ageing process can be accompanied by a degeneration of the spine and increase the risk of thoracic hyperkyphosis.The use of corrective orthotic bracing has been shown to improve spinal posture, and increase stability and balance amongst the elderly.Using a TLSO decreases forefoot pressures in stasis, and around the first metatarsal, as well as pressures relating to the second to fifth metatarsals under dynamic conditions.

Correction of Planovalgus Deformity Through Rotational Reinsertion of the Lateral Layers of the Achilles Tendons in Ambulatory Children With Cerebral Palsy

Symptomatic planovalgus deformity is a condition commonly seen in patients with cerebral palsy. The authors propose a new procedure for the management of this deformity through rotational reinsertion of the lateral layers of the Achilles tendon, and then they assess its benefit by comparing plantar pressure distribution patterns in children preoperatively and at 6- and 12-month intervals postoperatively. Pedobarographic measurements, range of motion of the ankle, and radiographic indexes were used to assess the outcome of the surgery. The functional abilities of the patients were assessed based on the Gross Motor Function Classification System. A total of 37 feet (22 patients) were included, with a mean ± standard deviation age at surgery of 11.8 ± 2.7 (range 9.1 to 14.5) years. All feet were managed through rotational reinsertion of the lateral layers of the Achilles tendon. Surgical correction of planovalgus has good outcomes. Significant changes were observed with statistical significance at the 5% (p ≤ .05) level in plantar pressure distribution in children preoperatively and at 6- and 12-month intervals postoperatively. The results show that the proposed method of surgery is effective in the correction of planovalgus in ambulatory children with cerebral palsy.

Preliminary study on verifying the detection of gait intention based on knee joint anterior displacement of gait slopes

This study investigated the feasibility of the Infrared (IR) sensor-based walking aids for detecting the gait intention. To compensate for the defects of Force Sensing Resistors (FSRs) or force sensors, such as the velocity control problem on gait slopes, we used IR sensors to investigate knee joint anterior displacement in order to recognize the gait intention. We also measure leg muscle activities and foot pressure, in order to verify our investigation. We placed two IR sensors on the rollator center to sense left and right leg walking intentions. We took EMG signals of four leg muscles, and analyzed them. Foot pressure analysis parameters were the measured force and mean pressure. We conducted experiments on twenty young healthy adults. The results show that knee joint anterior displacement increases according to gait slope and velocity. We confirm similar results of knee joint anterior displacement through the IR sensors.

The evolution of compliance in the human lateral mid-foot

Fossil evidence for longitudinal arches in the foot is frequently used to constrain the origins of terrestrial bipedality in human ancestors. This approach rests on the prevailing concept that human feet are unique in functioning with a relatively stiff lateral mid-foot, lacking the significant flexion and high plantar pressures present in non-human apes. This paradigm has stood for more than 70 years but has yet to be tested objectively with quantitative data. Herein, we show that plantar pressure records with elevated lateral mid-foot pressures occur frequently in healthy, habitually shod humans, with magnitudes in some individuals approaching absolute maxima across the foot. Furthermore, the same astonishing pressure range is present in bonobos and the orangutan (the most arboreal great ape), yielding overlap with human pressures. Thus, while the mean tendency of habitual mechanics of the mid-foot in healthy humans is indeed consistent with the traditional concept of the lateral mid-foot as a relatively rigid or stabilized structure, it is clear that lateral arch stabilization in humans is not obligate and is often transient. These findings suggest a level of detachment between foot stiffness during gait and osteological structure, hence fossilized bone morphology by itself may only provide a crude indication of mid-foot function in extinct hominins. Evidence for thick plantar tissues in Ardipithecus ramidus suggests that a human-like combination of active and passive modulation of foot compliance by soft tissues extends back into an arboreal context, supporting an arboreal origin of hominin bipedalism in compressive orthogrady. We propose that the musculoskeletal conformation of the modern human mid-foot evolved under selection for a functionally tuneable, rather than obligatory stiff structure.

Generalized joint laxity associated with increased medial foot loading in female athletes

CONTEXT

The relationship between generalized joint laxity and plantar pressure distribution of the foot and the potential implications for lower extremity injury have not been studied.

OBJECTIVE

To determine the relationship between generalized joint laxity and dynamic plantar pressure distribution. We hypothesized that individuals with greater generalized joint laxity, or hypermobility, would have greater dynamic medial midfoot pressure and loading during walking than nonhypermobile individuals.

DESIGN

Case control.

SETTING

Institutional biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

Participants included 112 female soccer players between 11 and 21 years of age.

MAIN OUTCOME MEASURE(S)

Each participant was tested for generalized joint laxity using the Beighton and Horan Joint Mobility Index (BHJMI; range, 0-9) and was categorized as having either high (BHJMI score >or=4) or low (BHJMI score <4) generalized joint laxity. Peak pressure and maximum force were calculated from a dynamic, barefoot plantar pressure distribution system.

RESULTS

Peak pressure and maximum force were greater in the 27 participants categorized as having high generalized joint laxity than in the 85 participants categorized as having low generalized joint laxity. The midfoot region exhibited greater loading in participants with high generalized joint laxity than in the other participants. We found an effect of BHJMI classification in the medial midfoot; peak pressure in the dominant (F(1,109) = 11.262, P = .001) and nondominant (F(1,109) = 14.32, P < .001) sides and maximum force in the dominant (F(1,109) = 7.88, P = .006) and nondominant (F(1,109) = 9.18, P = .003) sides were greater in the high generalized joint laxity group than in the low generalized joint laxity group.

CONCLUSIONS

Athletes classified as having high generalized joint laxity demonstrated increased midfoot loading. Delineation of risk factors for medial collapse of the foot, which include hypermobility in athletes, may help clinicians evaluate and prevent lower extremity injury with treatments, such as orthoses.