Surface effects on in-shoe plantar pressure and tibial impact during running

Purpose： This study aims to explore the effects of running on different surfaces on the characteristics of in-shoe plantar pressure and tibial acceleration. Methods： Thirteen male recreational runners were required to run at 12 km/h velocity on concrete, synthetic track, natural grass, a normal treadmill, and a treadmill equipped with an ethylene vinyl acetate （EVA） cushioning underlay （treadmill_EVA）, respectively. An in-shoe plantar pressure system and an accelerometer attached to the tibial tuberosity were used to record and analyze the characteristics of plantar pressure and tibial impact during running. Results： The results showed that there were no significant differences in the 1 st and 2nd peak plantar pressures （time of occurrence）, pressure-time integral, and peak pressure distribution for the concrete, synthetic, grass, and normal treadmill surfaces. No significant differences in peak positive acceleration were observed among the five tested surface conditions. Compared to the concrete surface, however, running on treadmillEVA showed a significant decrease in the 1st peak plantar pressure and the pressure time integral for the impact phase （p 〈 0.05）. These can be further ascribed to a reduced peak pressure observed at heel region （p 〈 0.05）. Conclusion： There may not be an inevitable relationship between the surface and the lower-limb impact in runners. It is, however, still noteworthy that the effects of different treadmill surfaces should be considered in the interpretation of plantar pressure performance and translation of such results to overground running.

Assessment of the Plantar Pressure, Muscle Strength and Balance in Patients with Type 2 Diabetes Mellitus in Cyprus

Aims: Diabetes Mellitus (DM) is a metabolic disorder which affects whole systems of human body. This study aimed to compare the strength of foot muscles, dynamic balance, and peak plantar pressure between diabetic patients before developing polyneuropathy and healthy peers. Methods: 21 people, 11 diabetic patients and 10 age-matched healthy peers, were included in the study. A manual muscle tester (model 01163 Lafayette) was used to assess muscle strength. Pedobarography was the device to determine the distribution of plantar pressure into nine regions of foot. Dynamic balance was also measured by using a mobile platform (Techno-body, PK 200 WL, Italy). Results: Diabetic and control groups had similar muscle strength and dynamic balance (p > 0.05). Most of the plantar pressure findings were also similar (p > 0.05). There were significant differences in only two regions of foot between two groups (p < 0.05). Conclusion: Diabetes Mellitus is not a factor influencing balance and muscle strength before polyneuropathy. However, it is possible to state that it may negatively affect the distribution of plantar pressure so clinians should assess and treat this distribution in the patients with DM.

Smart passive gait retraining intervention via pebbles for reducing peakplantar pressure: Short-term results

Recently, there has been a growing interest in gait retraining to alter the gait parameters of different populations.In these gait retraining, peak plantar pressure (PPP) was considered as an important parameter of the footbiomechanics. It has been found that high PPP correlates to the common foot deformities including pes planus/cavus. However, previous studies utilized excessive electronics in gait retraining, which is challenging toimplement daily especially when device cleaning, flexibility and portability are considered. Therefore, this studyinvestigated feasibility of a novel unpowered gait retraining for reducing high PPP. Twelve potential participantsidentified for investigation through a baseline PPP evaluation with Novel Pedar-x system. Participants received asingle session for the gait retraining with pebbles in the form of rigid spherical inserts (RSI) placed in locations ofhigh PPP inside the deformable insole. This provides tactile cues alerting the participants to alter their gait toreduce excess PPP. The PPP values were tracked in weekly follow-up sessions for 6 weeks. The results demonstrated that participants responded to RSI altering their gait to reduce PPP and maximum force by 14% and 10.5%after six weeks respectively. This study is valuable for physicians in reducing PPP when non-electronics arerequired.

Regional plantar foot pressure distributions on high-heeled shoes-shank curve effects

Forefoot pain is common in high-heeled shoe wearers due to the high pressure caused by the center of body mass moving forward and the increased arch height with heel elevation.Sufficient arch support could reduce the high pressure over forefoot.However,too much arch support could lead to abnormal foot alignment and pain over midfoot.Little information is reported on the relationship among plantar arch height,shank curve design and plantar pressure.This study aimed at quantifying the plantar arch height changes at different heel heights and investigating the effect of shank curve on plantar pressure distribution.The plantar arch height increased to（7.6±1.3） mm at heel height of 75 mm.The Chinese standard suggests the depth of last should be 8.5 mm for heel height of 75 mm.When a shank curve with higher depth of last（11 mm） was used,the peak pressure over forefoot further decreased in midstance phase,which might ease the forefoot problems,while the peak pressure over midfoot increased but not exceeded the discomfort pressure thresholds.To achieve a more ideal pressure distribution in high-heeled shoes,a higher than expected depth of last would be suggested that would not cause discomfort over midfoot.

Plantar Pressure Changes and Correlating Risk Factors in Chinese Patients with Type 2 Diabetes： Preliminary 2-year Results of a Prospective Study

Background： Plantar pressure serves as a key factor for predicting ulceration in the feet of diabetes patients. We designed this study to analyze plantar pressure changes and correlating risk factors in Chinese patients with type 2 diabetes. Methods： We recruited 65 patients with type 2 diabetes. They were invited to participate in the second wave 2 years later. The patients completed identical examinations at the baseline point and 2 years later. We obtained maximum force, maximum pressure, impulse, pressure-time integral, and loading rate values from 10 foot regions. We collected data on six history-based variables, six anthropometric variables, and four metabolic variables of the patients. Results： Over the course of the study, significant plantar pressure increases in some forefoot portions were identified （P 〈 0.05）, especially in the second to forth metatarsal heads. Decreases in heel impulse and pressure-time integral levels were also found （P 〈 0.05）. Plantar pressure parameters increased with body mass index （BMI） levels. Hemoglobin Alc （HbAlc） changes were positively＇ correlated with maximum force （β = 0.364, P = 0.001） and maximum pressure （β= 0.366, P = 0.002） changes in the first metatarsal head. Cholesterol changes were positively correlated with impulse changes in the lateral portion of the heel （β = 0.179, P = 0.072） and pressure-time integral changes in the second metatarsal head （β = 0.236, P = 0.020）. Ankle-brachial index （ABI） changes were positively correlated with maximum force changes in the first metatarsal head （β = 0.137, P = 0.048）. Neuropathy symptom score （NSS） and common peroneal nerve sensory nerve conduction velocity （SCV） changes were positively correlated with some plantar pressure changes. In addition, plantar pressure changes had a correlation with the appearance of infections, blisters （β = 0.244, P = 0.014）, and calluses over the course of the study. Conclusions： We should pay attention to the BMI, HbAlc, cholesterol, ABI, SCV, and NSS changes in the process of preventing high plantar pressure and ulceration. Some associated precautions may be taken with the appearance of infections, blisters, and calluses.

Dynamic biomechanical effect of lower body positive pressure treadmill training for hemiplegic gait rehabilitation after stroke: A case report

BACKGROUND Lower body positive pressure(LBPP)treadmill has potential applications for improving the gait of patients after stroke,but the related mechanism remains unclear.CASE SUMMARY A 62-year-old male patient suffered from ischemic stroke with hemiplegic gait.He was referred to our hospital because of a complaint of left limb weakness for 2 years.The LBPP training was performed one session per day and six times per week for 2 wk.The dynamic plantar pressure analysis was taken every 2 d.Meanwhile,three-digital gait analysis and synchronous electromyography as well as clinical assessments were taken before and after LBPP intervention and at the 4-wk follow-up.During LBPP training,our patient not only improved his lower limb muscle strength and walking speed,but more importantly,the symmetry index of various biomechanical indicators improved.Moreover,the patient’s planter pressure transferring from the heel area to toe area among the LBPP training process and the symmetry of lower body biomechanical parameters improved.CONCLUSION In this study,we documented a dynamic improvement of gait performance in a stroke patient under LBPP training,which included lower limb muscle strength,walking speed,and symmetry of lower limb biomechanics.Our study provides some crucial clues about the potential dynamic mechanism for LBPP training on gait and balance improvement,which is related to rebuilding foot pressure distribution and remodeling symmetry of biomechanics of the lower limb.

Biomechanical evaluation of heel elevation on load transfer——experimental measurement and finite element analysis

In spite of ill-effects of high heel shoes, they are widely used for women. Hence, it is essential to understand the load transfer biomechanics in order to design better fit and comfortable shoes. In this study, both experimental measurement and finite element analysis were used to evaluate the biomechanical effects of heel height on foot load transfer. A controlled experiment was conducted using custom-designed platforms. Under different weight-bearing conditions, peak plantar pressure, contact area and center of pressure were analyzed. A three-dimensional finite element foot model was used to simulate the high-heel support and to predict the internal stress distributions and deformations for different heel heights. Results from both experiment and model indicated that heel elevations had significant effects on all variables. When heel elevation increased, the center of pressure shifted from the midfoot region to the forefoot region, the contact area was reduced by 26% from 0 to 10.2 cm heel and the internal stress of foot bones increased. Prediction results also showed that the strain and total tension force of plantar fascia was minimum at 5.1 cm heel condition. This study helps to better understand the biomechanical behavior of foot, and to provide better suggestions for design parameters of high heeled shoes.

The characteristics of walking strategy in elderly patients with type 2 diabetes

Objective:To explore the walking strategy by monitoring the characteristics of center of pressure(COP)of gait in the elderly with type2 diabetes.Methods:All of the elderly patients with type2 diabetes(n=543)were enrolled from Huadong Hospital Affiliated to Fudan University.Dynamic barefoot plantar pressure was assessed by Footscan7 USB2 flat.Outcome measures included excursion,the x-and ycoordinates displacement of COP and falling frequency.Results:There were 64.5%of cases with abnormal COP trajectory.Among them,45.2%were with abnormal fold-back,14.0%with two or more abnormal fold-back,20.5%with abnormal beginning point deviating from the heel to the arch and metatarsal region,18.0%with abnormal terminal point deviating from the hallux to toe 2e5 and the x-and y-coordinates displacement of COP in both feet are asymmetry.Conclusions:It highlights to put forward the walking strategy according to the abnormal COP trajectory.Due to the elderly diabetics with high risks of falling,the rehabilitation nursing should be strengthened mainly including the training of enhancing proprioception to prevent the elderly patients with type2 diabetes from falling.

An In Vivo Experimental Validation of a Computational Model of Human Foot

Reliable computational foot models offer an alternative means to enhance knowledge on the biomechanics of human foot. Model validation is one of the most critical aspects of the entire foot modeling and analysis process.This paper presents an in vivo experiment combining motion capture system and plantar pressure measure platform to validate a three-dimensional finite element model of human foot.The Magnetic Resonance Imaging(MRI)slices for the foot modeling and the experimental data for validation were both collected from the same volunteer subject.The validated components included the comparison of static model predictions of plantar force,plantar pressure and foot surface deformation during six loading conditions,to equivalent measured data.During the whole experiment,foot surface deformation,plantar force and plantar pressure were recorded simultaneously during six different loaded standing conditions.The predictions of the current FE model were in good agreement with these experimental results.

Plantar ROI Characterization during the Stance Phase of Gait Based on a Low-cost Pressure Acquisition Platform

Plantar Region of Interest （ROI） detection is important for the early diagnosis and treatment ofmorphologic defects of the foot and foot bionic research. Conventional methods have employed complex procedures and expensive instruments which prohibit their widespread use in healthcare. In this paper an automatic plantar ROIs detection method using a customized low-cost pressure acquisition device is proposed. Plantar pressure data and 3D motion capture data were collected from 28 subjects （14 healthy subjects and 14 subjects with hallux valgus）. The maximal inter-frame difference during the stance phase was calculated. Consequently, the ROIs were defined by the first-order difference in combination with prior anatomic knowl- edge. The anatomic locations were determined by the maximal inter-frame difference and second maximal inter-frame differ- ence, which nearly coincided. Our system can achieve average recognition accuracies of 92.90%, 89.30%, 89.30%, 92.90%, 92.90%, and 89.30% for plantar ROIs hallux and metatarsi I-V, respectively, as compared with the annotations using the 3D motion capture system. The maximal difference of metatarsus heads II-V, and the impulse of the medial and lateral heel features made a significant contribution to the classification ofhallux valgus and healthy subjects with ≥ 80% sensitivity and specificity. Furthermore, the plantar pressure acquisition system is portable and convenient to use, thus can be used in home- or commu- nity-based healthcare applications.

Therapeutic smart-footwear approach for management of neuropathic diabetic foot ulcers:Current challenges and focus for future perspective

Diabetic foot ulcers(DFU)have been connected to rising global mortality rates.An increased plantar tissue stress beneath the numb foot of neuropathy patients is associated with DFU.This article summarises essential therapeutic footwear concepts for the treatment of DFUs and shows how new sensor technologies have made this possible.People with neuropathic DFUs can address their foot problems with therapeutic footwear without being constrained in their daily activities.This intervention in maintaining DFUs must be discrete,power-efficient,accurate,and user-friendly in order to offer a trustworthy and acceptable way for effective health monitoring.The device can be inserted into a person's shoes from the plantar aspect of the foot to gather more information about their health.The findings showed that weight-bearing activities and sensor offloading devices can be employed as effective offloading therapies to heal DFU.This article examines the therapeutic footwear-based technological sensor system,which keeps track of many elements that are helpful in tracking foot ulcers,available treatments,and potential research areas in the future.

The interaction effects of rocker angle and apex location in rocker shoe design on foot biomechanics and Achilles tendon loading

The influences of rocker shoes on foot biomechanics were controversial because the interaction between two design factors—rocker angle and apex location,was usually omitted.This study investigated the interaction effects of rocker angle and apex location on plantar foot pressure,metatarsophalangeal/ankle angle,and Achilles tendon force during walking.Ten participants performed walking trials under six rocker shoe conditions:2 rocker angles(mild and severe)×3 apex locations(distal,standard,and proximal),wherein the plantar foot pressure was measured and the movement data were processed by musculoskeletal modeling to report joint angle and Achilles tendon force.A two-way ANOVA repeated measures was used for statistics.Significant interaction effects were reported in examinations of forefoot pressure,midfoot pressure,and metatarsophalangeal dorsiflexion.The standard apex significantly reduced peak forefoot and midfoot pressures(p=0.008–0.034,Hedges'g=0.75–0.84),which was further decreased by a severe rocker angle(p=0.006,Hedges'g=0.51–0.81).Moving the apex proximally reduced Achilles tendon forces(p<0.001,Hedges'g=0.80)and facilitated both metatarsophalangeal dorsiflexion and ankle plantarflexion during push-off(p=0.003–0.006,Hedges'g=0.03–0.82).Rocker angle seemed to have fewer effects on ankle joint angle and Achilles tendon force.We concluded that apex location was likely the dominant design factor of the rocker sole in influencing foot biomechanics,yet its interactions with rocker angle should be considered.The configuration of the two features could be varied to possess different therapeutic merits and adapt to specific application purposes.

Effects of Shoe Heel Height on Loading and Muscle Activity for Trans-Tibial Amputees During Standing

This study accesses the effects of shoe heel heights on loading, muscle activity, and plantar foot pressure of trans-tibial amputees during standing. Five male subjects with unilateral trans-tibial amputation volunteered to participate in this study. Three pairs of shoes with zero, 20 mm, and 40 mm heel heights were used. The loading line of the prosthetic side, the plantar foot pressure, and the surface electromyography （EMG） of 10 muscles were simultaneously recorded. With increasing shoe heel heights during standing, the loading line of the prosthetic side shifted from the anterior to the posterior side of the knee center, the peak pressure was increased in the medial forefoot region, and the peak pressure was reduced in the heel region. The EMG of the medial and lateral gastrocnemius of the sound leg almost doubled and that of the rectus fomris, vastus lateralis, and vastus medialis of the prosthetic side increased to different extents with in- creasing heel heights from zero to 40 mm. These results show a high correlation with human physical be- havior. Changing of the heel heights for trans-tibial amputees during standing actually had similar effects to altering the prosthetic sagittal alignment. The results suggest that an alignment change is necessary to accommodate heel height changes and that prosthesis users should be cautious when choosing shoes.