Dynamic Foot Research Articles

Changes in foot posture evaluated with dynamic pedobarography over the course of childhood in ambulatory youth with cerebral palsy.

Foot deformities are prevalent in children with cerebral palsy, but there is limited research on the progression of foot posture during growth. Our study aimed to evaluate the change in dynamic foot posture in children with cerebral palsy. Children with cerebral palsy, aged 17-40 months, were recruited to participate in this Institutional Review Board-approved prospective longitudinal study by having serial foot posture evaluations. The coronal plane index and foot segmental impulses were measured with dynamic pedobarography. Data were compared between children stratified by Gross Motor Function Classification System level and typically developing children using serial Welch's t-tests across time with Holm correction for multiple comparisons. In total, 33 children (54 limbs) were included in the analysis (21 bilateral and 12 unilateral; Gross Motor Function Classification System: I-13, II-14, III-4, IV-2. Children completed 16.9 (± 4.4) evaluations (initial age 2.9 (± 0.7) and final age 18.6 (± 1.7) years)). Early valgus foot posture normalizes in children at Gross Motor Function Classification System levels I/II and persists in children at levels III/IV who do not have foot surgery. For most young children, foot posture development is variable. Foot posture in young children with cerebral palsy begins in valgus and tends to normalize in youth who walk without an assistive device. Conservative management of foot deformity is recommended in early childhood. Level II, prognostic study.

Data-Driven Modeling of the Nonlinear Dynamics of Passive Lower-Limb Prosthetic Systems

Abstract Modeling the nonlinear dynamics of prosthetic feet is an important tool for linking prosthesis mechanical properties to end-user outcomes. There has been a renewed interest in data-driven modeling of dynamical systems, with the development of the Extended Dynamic Mode Decomposition with control (eDMDc) and the Sparse Identification of Nonlinear Dynamics with Control (SINDYc). These algorithms do not require prior information about the system, including mechanical configuration, and are data-driven. The aim of this study was to assess the feasibility and accuracy of applying these data-driven algorithms to model prosthesis nonlinear load response dynamics. Different combinations of a dynamic response foot, a hydraulic ankle unit, and three shock-absorbing pylons of varying resistance were tested loaded and unloaded at three orientations reflecting critical positions during the stance phase of walking. We tested two different data-driven algorithms, the eDMDc, with two different kernels, and the SINDYc, which regresses the coefficients for a nonlinear ordinary differential equation. Each algorithm was able to model the nonlinear prosthesis dynamics, but the SINDYc outperformed the eDMDc methods with a root mean square error across orientations < 1.50 mm and a maximum error in peak displacement of 1.28 mm or 4% relative error. From the estimated SINDYc governing equation of the system dynamics, we were able to simulate different mechanical behavior by systematically varying parameter values, which offers a novel foundation for designing, controlling, and classifying prosthetic systems ultimately aimed at improving prosthesis user outcomes.

Technical note: A volumetric method for measuring the longitudinal arch of human tracks and feet.

Fossil footprints (i.e., tracks) were believed to document arch anatomical evolution, although our recent work has shown that track arches record foot kinematics instead. Analyses of track arches can thereby inform the evolution of human locomotion, although quantifying this 3-D aspect of track morphology is difficult. Here, we present a volumetric method for measuring the arches of 3-D models of human tracks and feet, using both Autodesk Maya and Blender software. The method involves generation of a 3-D object that represents the space beneath the longitudinal arch, and measurement of that arch object's geometry and spatial orientation. We provide relevant tools and guidance for users to apply this technique to their own data. We present three case studies to demonstrate potential applications. These include, (1) measuring the arches of static and dynamic human feet, (2) comparing the arches of human tracks with the arches of the feet that made them, and (3) direct comparisons of human track and foot arch morphology throughout simulated track formation. The volumetric measurement tool proved robust for measuring 3-D models of human tracks and feet, in static and dynamic contexts. This tool enables researchers to quantitatively compare arches of fossil hominin tracks, in order to derive biomechanical interpretations from them, and/or offers a different approach for quantifying foot morphology in living humans.

Static and dynamic plantar foot shape following long-term use of military boots

Foot structure can be influenced by various factors, such as footwear, body weight and physical activity. A change in foot structure can alter shock absorption and force transition. The main objective of this study is to investigate the effect of the long-term use of military boots on foot shape parameters. Thirty military and thirty non-military subjects participated in this case-control study. All participants had been regularly wearing military boots for the past 12 years. After introducing the experiment, static and dynamic footprints were recorded via paper and ink while standing and walking. The footprints were analysed using ImageJ software to extract foot width indices, area indices, truncated arch index, footprint index and arch angle index. The findings indicated no significant difference in comparison static and dynamic variables in the military and non-military groups (p ≥ 0.05). However, there was a significant difference between the two groups in both static (midfoot area, arch index (AI), truncated arch index, footprint index and arch angle index) and dynamic (midfoot width, Staheli Index (SAI), truncated arch index and arch angle index) conditions, when static and dynamic variable were compared (p < 0.05). Findings revealed the military personnel have low arch, making them susceptible to musculoskeletal disorders. To mitigate this risk, it is recommended that military boots be reassessed or that insoles be used. Furthermore, it is suggested that military boots be limited to specific activities and fewer hours of usage to avoid potential health issues.

Hip joint and muscle loading for persons with bilateral transfemoral/through-knee amputations: biomechanical differences between full-length articulated and foreshortened non-articulated prostheses

BackgroundCurrently, there is little available in-depth analysis of the biomechanical effect of different prostheses on the musculoskeletal system function and residual limb internal loading for persons with bilateral transfemoral/through-knee amputations (BTF). Commercially available prostheses for BTF include full-length articulated prostheses (microprocessor-controlled prosthetic knees with dynamic response prosthetic feet) and foreshortened non-articulated stubby prostheses. This study aims to assess and compare the BTF musculoskeletal function and loading during gait with these two types of prostheses.MethodsGait data were collected from four male traumatic military BTF and four able-bodied (AB) matched controls using a 10-camera motion capture system with two force plates. BTF completed level-ground walking trials with full-length articulated and foreshortened non-articulated stubby prostheses. Inverse kinematics, inverse dynamics and musculoskeletal modelling simulations were conducted.ResultsFull-length articulated prostheses introduced larger stride length (by 0.5 m) and walking speed (by 0.3 m/s) than stubbies. BTF with articulated prostheses showed larger peak hip extension angles (by 10.1°), flexion moment (by 1.0 Nm/kg) and second peak hip contact force (by 3.8 bodyweight) than stubbies. There was no difference in the hip joint loading profile between BTF with stubbies and AB for one gait cycle. Full-length articulated prostheses introduced higher hip flexor muscle force impulse than stubbies.ConclusionsCompared to stubbies, BTF with full-length articulated prostheses can achieve similar activity levels to persons without limb loss, but this may introduce detrimental muscle and hip joint loading, which may lead to reduced muscular endurance and joint degeneration. This study provides beneficial guidance in making informed decisions for prosthesis choice.

Assessment and indicators of hallux limitus related with quality of life and foot health in school children.

Functional Hallux Limitus (FHL) is a dynamic foot dysfunction characterized by a limitation of hallux dorsiflexion when the first metatarsal head is under load. FHL plays a role in the development of osteoarthrosis in the first metatarsophalangeal joint (IMTPJ). Forefoot disorders can significantly impact an individual's quality of life, leading to dysfunction and pain. The aim of this project was to evaluate the quality of life of school-aged individuals with and without FHL using the Foot Health Status Questionnaire (FHSQ). A case-control study was conducted to evaluate the outcomes in paediatric age. A total sample of 116 children between 6 and 12 years old was used to conduct this research. The sample was divided into two groups: (i) the healthy group (n = 58) and the FHL group (n = 58). The FHSQ was completed and the FHL test was performed in a seated position to classify the patients into the selected group. Non-significant changes were observed when the mean values of the FHSQ domains were compared between the groups with and without FHL, except for the "general foot health" domain (p = 0,024) associated with the specific foot health section (section 1) of the Questionnaire. For the domains linked with the general well-being section (section 2), there was not a statistically difference in the mean of the scores obtained between the two school-aged groups with and without FHL, being slightly lower in the group with the presence of FHL for the overall health and physical function domains. Both the healthy and case groups obtained and identical range of scores (10-100) for the "foot pain" domain. Nevertheless, the mean of the score was lower for the participants with FHL. The perception of the quality of general foot health was poorer in the school-aged group with FHL. Variables such as foot pain and footwear are likely contributors influencing the perception of foot health quality. The school-aged population with FHL faces a decline in the quality of foot life. Ensuring adequate foot control in children and implementing future foot programs for this population are imperative for enhancing school children's perception of foot health and managing the development of pain and footwear-related issues.

“Antero-medial load shift” in unilateral plantar heel pain – A cross-sectional exploratory study

Background and purposePlantar foot pressure provides an insightful data in the ankle and foot complex which may aid in the detection of underlying pathology. Since individuals with unilateral plantar heel pain (PHP) tend to develop compensatory loading strategies, this study aimed to observe the foot loading pattern compared to the asymptomatic side and its relationship with the morphological variations in individuals with unilateral PHP. MethodsIt was a prospective cross-sectional study done on 17 participants with unilateral PHP. The calcaneal inclination and calcaneal first metatarsal angles were measured using lateral weight-bearing radiographs for both symptomatic and asymptomatic feet. Static and dynamic plantar foot pressures for both sides were obtained using a “Portable baropodometry platform 0, 5 m Entry Level footscan®. ResultsOn the symptomatic side, the pressure in the lateral heel was reduced by 65% in static and 67% in dynamic measurements, while in the medial heel, it was reduced by 16 % in static and 47 % in dynamic measurements compared to that of the asymptomatic side. There was a transfer of pressure from the hind foot to the forefoot by 44 % in static and 46 % in dynamic measurements resulting in anterior load shift. It was also observed that the prevalence of PHP was higher in the normal arched foot (59%). ConclusionBased on the observations, compared to the asymptomatic side, patients with unilateral plantar heel pain exhibited an anteromedial load shift (AMLS) in their plantar pressures. PHP was reported higher in the foot with normal morphology. Level of evidenceLevel 4.

Vibration perception among children and adolescents with Charcot-Marie-tooth disease and implications for foot posture

BackgroundAlterations in vibration perception among children and adolescents with Charcot-Marie-Tooth disease might explain observed changes in foot posture. Therefore, this cross-sectional study compared the vibration perception of the lower limbs in youths with and without Charcot-Marie-Tooth disease and verified the cut-off value of the distal vibration perception for the Charcot-Marie-Tooth group. In addition, associations between dynamic plantar pressure, vibration perception and isometric muscle strength were investigated. MethodsParticipants aged 9–18 (Charcot-Marie-Tooth group n = 32; Typical group n = 32) had vibration perception measured by a 128-Hz graduated tuning fork. The static and dynamic foot posture were evaluated by the Foot Posture Index and pressure distribution measuring system, respectively. For the Charcot-Marie-Tooth group, a hand-held dynamometer evaluated the isometric muscle strength of the lower limbs. FindingsChildren with Charcot-Marie-Tooth disease presented impaired vibration perception at the distal phalanx of the hallux and head of the first metatarsal compared to their typically developing peers, while adolescents with Charcot-Marie-Tooth disease showed impairment in all the tested regions compared to their typically developing peers. The cut-off value for vibration perception for participants with Charcot-Marie-Tooth disease was 5.7, considering the original grade of the tuning-fork 128 Hz. Among the associations established for the Charcot-Marie-Tooth group, a greater vibration perception at the distal phalanx of the hallux was associated with a longer rearfoot contact time (β = 31.02, p = 0.04). InterpretationThese new findings may guide the clinical evaluation and rehabilitation treatment for children and adolescents with Charcot-Marie-Tooth disease.

Static and Dynamic Foot Pressure Changes Among Diabetic Patients With and Without Neuropathy: A Comparative Cross-Sectional Study.

Foot ulceration is a frequent diabetic complication with potentially fatal consequences. The pathophysiology of neuropathic ulcers in the diabetic foot is thought to be influenced by abnormal plantar pressures. This study aimed to compare the maximum peak pressures among diabetic patients with and without neuropathy. The secondary aim was to evaluate the effect of glycemic control on pressure changes in both feet. The study used 62 diabetic individuals as participants. BMI was calculated, as well as illness duration, hemoglobin A1c, and the existence of neuropathy. Plantar pressure was measured in static (standing) and dynamic (walking/taking a step on the mat) settings for all patients using the BTS P-Walk system. The plantar pressures (kPa) at the five metatarsal regions, the midfoot region, and the medial and lateral heel regions were measured. We found that the dynamic maximum pressures were significantly higher in patients with diabetic neuropathy (DN) compared to diabetics without neuropathy at the first metatarsal and mid-foot area in both feet (p<0.05). We also found significantly elevated plantar pressure in patients with poor glycemic control under the second metatarsal head in the right foot (p<0.05). Persons with DN have higher maximum plantar pressures compared to diabetics without neuropathy. Patients with poor glycemic control also have a higher maximum pressure.

Factors Related to Relapse of Congenital Talipes Equinovarus (CTEV) After the Ponseti Method.

Congenital talipes equinovarus (CTEV) is one of the common congenital disorders in pediatric orthopedic practice that affects a large group of children.It is a combination of four parts of deformity that affect either a single foot or both feet. Our aim in this study is to estimate the prevalence and incidence of CTEV and to evaluate the risk factors that lead to relapse in some children to avoid relapse in future and complex surgical interventions, as well as to improve the final outcome. A retrospective cohort study for the cases of CTEV was conducted to estimate the prevalence of relapse in children with CTEV after management by the Ponseti method and to evaluate the risk factors that lead to recurrence. The study includes 103 patients with CTEV, and only 22 patients had relapse. The prevalence rate of relapsed cases was 20.4%, and the incidence was 42 per thousand. The average number of casts applied was 4.05 ± 1.37. The average severity of the deformity that was measured by the Pirani score was 4.97 ± 1.21. The most common atypical presentation of CTEV was associated with developmental dysplasia of the hip (DDH), followed by myelomeningocele (MMC). The only significant factors in the study were the Pirani score and non-compliance of the brace with p < 0.05. There was not any significance in the correction of the deformity by Ponseti between idiopathic and non-idiopathic CTEV based on the number of casts and the Pirani score. The dynamic foot brace can be the solution for the high recurrence rate, yet more studies are needed in the future.

Symmetry Function in Trans-Tibial Amputees Gait Supplied with the New Concept of Affordable Dynamic Foot Prosthesis—Case Study

The development of modern technologies has made it much easier to regain the ability to walk after losing a lower limb. The variety of prosthetic feet available on the market allows for optimal choice and appropriate adjustment of the foot prosthesis to the trans-tibial amputee patient’s needs. Unfortunately, the best solutions are often not available to everyone due to their high prices. This study compares the gait patterns of patients using the new concept of an affordable dynamic foot with those of other commonly available but much more expensive foot prostheses. The kinematic and spatio-temporal parameters of gait obtained using the motion capture system were analyzed. For a clear picture of changes in bilateral deficits during gait for the pelvis, hip, knee, and ankle joints, the symmetry function was used. The results indicate that the new and cheaper concept of foot prostheses offers a very similar level of gait quality to that provided by more expensive and popular solutions. The authors suggest that the use of symmetry function thresholds of 10% does not work for amputees.

Intrinsic Foot Muscle Exercises With and Without Electric Stimulation.

Exercising intrinsic foot muscles (IFMs) can improve dynamic balance and foot posture. The exercises are not intuitive and electrotherapy (neuromuscular electrical stimulation [NMES]) has been suggested to help individuals execute the exercises. The aim of this study was to evaluate the effects of training IFM program on dynamic balance and foot posture and compare traditional training methods (TRAIN) with traditional training plus NMES on the perceived workload of the exercises, balance, and foot posture. Randomized controlled trial. Thirty-nine participants were randomized to control, TRAIN, or NMES. TRAIN and NMES performed IFM exercises daily for 4weeks; NMES received electrotherapy during the first 2weeks of training. The Y-Balance test and arch height index were measured in all participants at baseline. The training groups were measured again at 2weeks; all participants were measured at 4weeks and 8weeks, after 4weeks of no training. Perceived workload (National Aeronautics and Space Administration Task Load Index) of exercises was assessed throughout the first 2weeks and at 4weeks. A 4-week IFM training program demonstrated increases in Y-Balance (P = .01) for TRAIN and in arch height index (seated P = .03; standing P = .02) for NMES, relative to baseline. NMES demonstrated improvement in Y-Balance (P = .02) and arch height index standing (P = .01) at 2weeks. There were no significant differences between the training groups. Groups were similar in the number responding to exercises in excess of minimal detectable change on all clinical measures. Perceived workload of the exercises decreased during the first 2weeks of training (P = .02), and more notably at 4weeks (P < .001). The groups did not differ in how they perceived the workload. A 4-week IFM training program improved dynamic balance and foot posture. Adding NMES in early phases of training provided early improvement in dynamic balance and foot posture, but did not affect perceived workload.

Effects of short foot exercise combined with lower extremity training on dynamic foot function in individuals with flexible flatfoot: A randomized controlled trial

BackgroundFlexible flatfoot has demonstrated biomechanical linkages between distal and proximal lower extremities. However, supporting evidence is required to investigate the benefits of short foot exercise (SF) and short foot exercise in combination with lower extremity training (SFLE) on dynamic foot function. Research questionThis study aimed to determine the effects of a 6-week SF, 6-week SFLE, or control condition (no intervention) on dynamic foot function during gait in individuals with flexible flatfoot. MethodsForty-five individuals with flexible flatfoot were randomly assigned into three conditions: (1) SF, (2) SFLE, and (3) control conditions. Participants in two intervention programs performed daily training via telerehabilitation and a home-based exercise program. Foot kinematics and center of pressure excursion index (CPEI) during the gait, intrinsic foot muscle test, and navicular drop test were assessed at baseline and after the 6-week intervention program. ResultsPost-intervention participants in the SF and SFLE conditions showed a shorter time to the lowest medial longitudinal arch (MLA) and improved MLA motion during the stance phase compared with the baseline. In addition, participants in the SFLE conditions showed greater changes in CPEI than in the SF and control conditions. Improvements in intrinsic foot muscle and navicular drop tests were also observed in participants in both intervention programs post-intervention. SignificanceA major finding of the study was the improvement in dynamic foot function during gait in individuals with flexible flatfoot after the six weeks of the SF and SFLE intervention programs. Both intervention programs appear to have the potential for inclusion in a corrective program for individuals with flexible flatfoot.

An exploratory study of dynamic foot shape measurements with 4D scanning system

Accurate and reliable foot measurements at different stances offer comprehensive geometrical information on foot, thus enabling a more comfortable insole/footwear for practical use and daily activities. However, there lacks investigations on continuous deformation of foot shape during the roll-over process. This study analyses the foot deformation of 19 female diabetic patients during half weight bearing standing and self-selected walking speed by using a novel 4D foot scanning system. The scanning system has good repeatability and accuracy in both static and dynamic scanning situations. Point cloud registration for scanned image reorientation and algorithms to automatically extract foot measurements is developed. During the foot roll-over process, maximum deformation of length and girth dimensions are found at first toe contact. Width dimensions have maximum deformation at heel take off. The findings provide a new understanding of foot shape changes in dynamic situations, thus providing an optimal solution for foot comfort, function and protection.

The influence of isometric resisted ankle strength on dynamic foot plantar pressure in diabetes and non-diabetes participants

&lt;b&gt;Introduction&lt;/b&gt;: Patients with diabetes are more likely to fall due to increased plantar pressure and decreased strength in the lower extremities.&lt;br /&gt; &lt;b&gt;Objectives:&lt;/b&gt; To determine the influence of isometric ankle strength on dynamic foot plantar pressure in diabetes and non-diabetes participants.&lt;br /&gt; &lt;b&gt;Methods: &lt;/b&gt;Twenty diabetes patients and twenty non-diabetes participants with age 28-54 years, height 150-182 cm, weight 48-90 kg, and BMI 25-54 kg/m&lt;sup&gt;2&lt;/sup&gt; participated in the study. The diabetes level was determined based on fasting plasma glucose levels. The resisted isometric muscle strength of the foot during dorsiflexion, plantar flexion, inversion, and eversion was measured using an electronic handheld dynamometer. The plantar pressure distribution during dynamic conditions was determined by using a 48.7×44.7 cm pressure platform. The outcome measures between diabetes and non-diabetes groups were statistically compared by student t-test. The correlation coefficient was determined by the Pearson correlation coefficient test. A p-value of less than 0.05 was considered significant.&lt;br /&gt; &lt;b&gt;Result: &lt;/b&gt;The significant differences were found between diabetes and non-diabetes participants for the dorsiflexion (p=.048), plantarflexion (p=.031), inversion (p=.011), eversion (p=.024), peak pressure (p=.024), pressure per square inch (p=.012), pressure time integral (p=.014), and peak pressure gradient (p=.009). Significant relationships between resisted isometric ankle joint strength and foot plantar pressure for diabetes patients and non-diabetes participants were found.&lt;br /&gt; &lt;b&gt;Conclusion: &lt;/b&gt;The present study’s findings reflect the higher frequency of plantar pressure distribution and higher muscle weakness in diabetes patients than in non-diabetes participants. These findings suggested that pressure data could help us to customize therapy strategies for patients with diabetes and prescribe a proper exercise intervention’s short-and long-term effects on gait biomechanics.

Assessment of Five-Foot Plantar Morphological Pressure Points of Children with Cerebral Palsy Using or Not Dynamic Ankle Foot Orthosis.

People with spastic cerebral palsy (CP) often experience a decline in gait function and flexion. The children's posture and hip strategy, which leads to knee flexion, predisposes these children to increased contact area in the medial foot region. This study investigated the use of DAFO (dynamic ankle-foot orthosis) prescribed to patients with cerebral palsy (CP) to determine the plantar pressure distribution with orthosis use. Eight children with spastic CP (age 4-12 years) were classified as Gross Motor Function Classification System (GMFCS) levels I-II with a maximum spasticity level of 3 in their ankle muscles according to the Modified Ashworth Scale. We assessed the plantar distribution by using eight WalkinSense sensors in each trial and exported data from the proprietary software (WalkinSense version 0.96, Tomorrow Options Microelectronics, S.A.). The plantar pressure distribution was conducted under two conditions: only shoes and DAFO with shoes. The activation percentages for sensor number 1 under the 1st metatarsal and sensor number 4 under the lateral edge of the heel were significantly different under the DAFO condition. The 1-point sensor activation percentage significantly decreased, while the 4-point sensor activation percentage increased during DAFO walking. According to our study findings, there was an increase in pressure distribution in the lateral part of the foot during the stance phase in DAFO. DAFO improved the gait cycle and influenced the plantar foot pressure in children with mild cerebral palsy.

Effects of foot intensive rehabilitation (FIRE) on clinical outcomes for patients with chronic ankle instability: a randomized controlled trial protocol

BackgroundLateral ankle sprains account for a large proportion of musculoskeletal injuries among civilians and military service members, with up to 40% of patients developing chronic ankle instability (CAI). Although foot function is compromised in patients with CAI, these impairments are not routinely addressed by current standard of care (SOC) rehabilitation protocols, potentially limiting their effectiveness. The purpose of this randomized controlled trial is to determine if a Foot Intensive REhabilitation (FIRE) protocol is more effective compared to SOC rehabilitation for patients with CAI.MethodsThis study will use a three-site, single-blind, randomized controlled trial design with data collected over four data collection points (baseline and post-intervention with 6-, 12-, and 24-month follow-ups) to assess variables related to recurrent injury, sensorimotor function, and self-reported function. A total of 150 CAI patients (50 per site) will be randomly assigned to one of two rehabilitation groups (FIRE or SOC). Rehabilitation will consist of a 6-week intervention composed of supervised and home exercises. Patients assigned to SOC will complete exercises focused on ankle strengthening, balance training, and range of motion, while patients assigned to FIRE will complete a modified SOC program along with additional exercises focused on intrinsic foot muscle activation, dynamic foot stability, and plantar cutaneous stimulation.DiscussionThe overall goal of this trial is to compare the effectiveness of a FIRE program versus a SOC program on near- and long-term functional outcomes in patients with CAI. We hypothesize the FIRE program will reduce the occurrence of future ankle sprains and ankle giving way episodes while creating clinically relevant improvements in sensorimotor function and self-reported disability beyond the SOC program alone. This study will also provide longitudinal outcome findings for both FIRE and SOC for up to two years. Enhancing the current SOC for CAI will improve the ability of rehabilitation to reduce subsequent ankle injuries, diminish CAI-related impairments, and improve patient-oriented measures of health, which are critical for the immediate and long-term health of civilians and service members with this condition.Trial Registration Clinicaltrials.gov Registry: NCT #NCT04493645 (7/29/20).

Mountain Hiking: Prolonged Eccentric Muscle Contraction during Simulated Downhill Walking Perturbs Sensorimotor Control Loops Needed for Safe Dynamic Foot–Ground Interactions

Safe mountain hiking requires precise control of dynamic foot-ground interactions. In addition to vision and vestibular afferents, limb proprioception, sensorimotor control loops, and reflex responses are used to adapt to the specific nature of the ground contact. Diminished leg dexterity and balance during downhill walking is usually attributed to fatigue. We investigated the supplementary hypothesis that the eccentric contractions inherent to downhill walking can also disrupt muscle proprioception, as well as the sensorimotor control loops and reflex responses that depend on it. In this study, we measured leg dexterity (LD), anterior-posterior (AP) and medio-lateral (ML) bipedal balance, and maximal voluntary leg extension strength in young and healthy participants before and after 30 min of simulated downhill walking at a natural pace on a treadmill at a 20° decline. Post-pre comparisons of LD (p < 0.001) and AP balance (p = 0.001) revealed significant reductions in dynamic foot-ground interactions after eccentric exercise without an accompanying reduction in leg extension strength. We conclude that eccentric contractions during downhill walking can disrupt the control of dynamic foot-ground interactions independently of fatigue. We speculate that mountaineering safety could be improved by increasing conscious attention to compensate for unadjusted proprioception weighting, especially in the descent.

Effects of Joint Mobilization and Stretching on Static- Dynamic Foot Pressure and Static Balance in Patients with Plantar Fasciitis

Effects of Joint Mobilization and Stretching on Static- Dynamic Foot Pressure and Static Balance in Patients with Plantar Fasciitis

Effect of painful Ledderhose disease on dynamic plantar foot pressure distribution during walking: a case-control study

BackgroundPlantar pressure distribution during walking in patients with painful Ledderhose disease is unknown. Research questionDo patients with painful Ledderhose disease have an altered plantar pressure distribution during walking compared to individuals without foot pathologies? It was hypothesized that plantar pressure is shifted away from the painful nodules. MethodsPedobarography data of 41 patients with painful Ledderhose disease (cases, mean age: 54.2 ± 10.4 years) was collected and compared to pedobarography data from 41 individuals without foot pathologies (controls, mean age: 21.7 ± 2.0 years). Peak Pressure (PP), Maximum Mean Pressure (MMP) and Force-Time Integral (FTI) were calculated for eight regions (heel, medial midfoot, lateral midfoot, medial forefoot, central forefoot, lateral forefoot, hallux and other toes) under the soles of the feet. Differences between cases and controls were calculated and analysed by means of linear (mixed models) regression. ResultsProportional differences in PP, MMP and FTI showed increased values for the cases compared to the controls, especially in the heel, hallux and other toes regions, and decreased values in the medial- and lateral midfoot regions. In naïve regression analysis, being a patient was a predictor for increased- and decreased values for PP, MMP and FTI for several regions. When dependencies in the data were taken into account with linear mixed-model regression analysis, the increased- and decreased values for the patients were most prevalent for FTI at the heel, medial midfoot, hallux and other toes regions. SignificanceIn patients with painful Ledderhose disease, during walking, a shift of pressure was found towards the proximal and distal foot regions, while offloading the midfoot regions.