Plantar Shear Stress Distribution in Patients with Rheumatoid Arthritis

2010 ◽  
Vol 100 (4) ◽  
pp. 265-269 ◽  
Author(s):  
Metin Yavuz ◽  
Elaine Husni ◽  
Georgeanne Botek ◽  
Brian L. Davis
Keyword(s):  
Rheumatoid Arthritis ◽  
Shear Stress ◽  
Plantar Pressure ◽  
Peak Pressure ◽  
Joint Inflammation ◽  
Shear Stresses ◽  
Vertical Loading ◽  
Time Integral ◽  
Pressure Profiles ◽  
Pressure Time

Background: Rheumatoid arthritis is an autoimmune disease that causes chronic, progressive joint inflammation; it commonly affects the joints of the feet. Biomechanical alterations and daily pain in the foot are the common outcomes of the disease. Earlier studies focusing on plantar pressure in such patients reported increased vertical loading along with peak pressure-pain associations. However, footwear designed according to the pressure profiles did not relieve symptoms effectively. We examined plantar shear and pressure distribution in patients with rheumatoid arthritis and compared the findings with those of controls, and we investigated a potential relationship between foot pain and local shear stresses. Methods: A custom-built platform was used to collect plantar pressure and shear stress data from nine patients with rheumatoid arthritis and 14 control participants. Seven patients reported the presence of pain under their feet. Pressure-time and shear-time integral values were also calculated. Results: Peak pressure, pressure-time integral, resultant shear-time integral, and mediolateral shear stress magnitudes were higher in the complication group (P < .05). An association between peak shear-time integral and maximum pain locations was observed. Conclusions: Increased mediolateral shear stresses under the rheumatoid foot might be attributable to gait instability in such patients. A correlation between the locations of maximum shear-time integral and pain indicate the clinical significance of plantar shear in patients with rheumatoid arthritis. (J Am Podiatr Med Assoc 100(4): 265–269, 2010)

Variability of plantar pressure data. A comparison of the two-step and midgait methods

1999 ◽  
Vol 89 (10) ◽  
pp. 495-501 ◽  
Author(s):  
TG McPoil ◽  
MW Cornwall ◽  
L Dupuis ◽  
M Cornwell
Keyword(s):  
Data Collection ◽  
Plantar Pressure ◽  
Peak Pressure ◽  
Pressure Data ◽  
Step Method ◽  
Plantar Surface ◽  
Time Integral ◽  
Risk Of Injury ◽  
Pressure Time ◽  
Reliable Representation

The number of trials required to obtain a reliable representation of the plantar pressure pattern is an important factor in the assessment of people with insensate feet or the use of plantar pressure data as a basis for fabrication of foot orthoses. Traditionally, the midgait method has been used for the collection of pressure data, but the large number of walking trials required by this method can increase the risk of injury to the plantar surface of the insensate foot. As a result, the two-step method of plantar pressure data collection has been advocated. The purpose of this investigation was to determine the degree of variability in regional plantar pressure measurements using the midgait and two-step methods of data collection. Plantar pressure data were collected from ten volunteers (five men and five women) between the ages of 20 and 35 years in 20 trials using both data-collection protocols. The results of the study indicate that three to five walking trials are needed to obtain reliable regional peak pressure and pressure-time integral values when the two-step data-collection protocol is used. Although either method can be used for pressure data collection, one method should be used consistently when repeated assessments are required.

Increased In-Shoe Lateral Plantar Pressures with Chronic Ankle Instability

2011 ◽  
Vol 32 (11) ◽  
pp. 1075-1080 ◽  
Author(s):  
Heather Schmidt ◽  
Lindsay D. Sauer ◽  
Sae Yong Lee ◽  
Susan Saliba ◽  
Jay Hertel
Keyword(s):  
Plantar Pressure ◽  
Peak Pressure ◽  
Ankle Instability ◽  
Chronic Ankle Instability ◽  
Maximum Force ◽  
Pressure System ◽  
Time To Peak ◽  
Time Integral ◽  
Pressure Time ◽  
Force Time

Background: Previous plantar pressure research found increased loads and slower loading response on the lateral aspect of the foot during gait with chronic ankle instability compared to healthy controls. The studies had subjects walking barefoot over a pressure mat and results have not been confirmed with an in-shoe plantar pressure system. Our purpose was to report in-shoe plantar pressure measures for chronic ankle instability subjects compared to healthy controls. Methods: Forty-nine subjects volunteered (25 healthy controls, 24 chronic ankle instability) for this case-control study. Subjects jogged continuously on a treadmill at 2.68 m/s (6.0 mph) while three trials of ten consecutive steps were recorded. Peak pressure, time-to-peak pressure, pressure-time integral, maximum force, time-to-maximum force, and force-time integral were assessed in nine regions of the foot with the Pedar-x in-shoe plantar pressure system (Novel, Munich, Germany). Results: Chronic ankle instability subjects demonstrated a slower loading response in the lateral rearfoot indicated by a longer time-to-peak pressure (16.5% ± 10.1, p = 0.001) and time-to-maximum force (16.8% ± 11.3, p = 0.001) compared to controls (6.5% ± 3.7 and 6.6% ± 5.5, respectively). In the lateral midfoot, ankle instability subjects demonstrated significantly greater maximum force (318.8 N ± 174.5, p = 0.008) and peak pressure (211.4 kPa ± 57.7, p = 0.008) compared to controls (191.6 N ± 74.5 and 161.3 kPa ± 54.7). Additionally, ankle instability subjects demonstrated significantly higher force-time integral (44.1 N/s ± 27.3, p = 0.005) and pressure-time integral (35.0 kPa/s ± 12.0, p = 0.005) compared to controls (23.3 N/s ± 10.9 and 24.5 kPa/s ± 9.5). In the lateral forefoot, ankle instability subjects demonstrated significantly greater maximum force (239.9N ± 81.2, p = 0.004), force-time integral (37.0 N/s ± 14.9, p = 0.003), and time-to-peak pressure (51.1% ± 10.9, p = 0.007) compared to controls (170.6 N ± 49.3, 24.3 N/s ± 7.2 and 43.8% ± 4.3). Conclusion: Using an in-shoe plantar pressure system, chronic ankle instability subjects had greater plantar pressures and forces in the lateral foot compared to controls during jogging. Clinical Relevance: These findings may have implications in the etiology and treatment of chronic ankle instability. Level of Evidence: III, Retrospective Case Control Study

The Effectiveness of Personalized Custom Insoles on Foot Loading Redistribution during Walking and Running

2020 ◽  
Vol 44 ◽  
pp. 1-8
Author(s):  
Yao Meng ◽  
Li Yang ◽  
Xin Yan Jiang ◽  
Bíró István ◽  
Yao Dong Gu
Keyword(s):  
Plantar Pressure ◽  
Peak Pressure ◽  
Young Males ◽  
Time Integral ◽  
Pressure Time ◽  
Mean Pressure ◽  
Pressure Maximum ◽  
Foot Loading ◽  
And Control ◽  
Better Than

The objective of this study was to investigate the effectiveness of different hardness of personalized custom insoles on plantar pressure redistribution in healthy young males during walking and running. Six males participated in the walking and running test (age: 24±1.6 years, weight: 67.9±3.6 kg, height: 175.5±4.7 cm). All subjects were instructed to walk and run along a 10m pathway wearing two different hardness insoles (i.e., hard custom insoles (CHI) and soft custom insole (CSI)) and control insole (CI) at their preferred speed. Peak pressure, mean pressure, maximum force, pressure-time integral were collected to analyze using SPSS. The plantar pressure of forefoot and medial midfoot were significantly increased and of lateral forefoot and lateral midfoot were decreased by both kinds of custom insoles in running tests. While the CHI significantly increased plantar pressure of the medial forefoot compared with the CSI and CI both in walking and running tests. The custom insoles showed significantly higher plantar pressure on medial midfoot. But CSI seems better than CHI because of redistributing the plantar pressure by increasing the plantar pressure of whole forefoot. Moreover, CSI showed significantly lower plantar pressure than CI and CHI at lateral midfoot during running test. The CHI causes significant high pressure at medial forefoot (MF), which may raise the risk of forefoot pain.

Immediate Effects of Weight-Bearing Calf Stretching on Ankle Dorsiflexion Range of Motion and Plantar Pressure During Gait in Patients with Diabetes Mellitus

2021 ◽  
pp. 153473462110313
Author(s):  
Noriaki Maeshige ◽  
Mikiko Uemura ◽  
Yoshikazu Hirasawa ◽  
Yoshiyuki Yoshikawa ◽  
Maiki Moriguchi ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Plantar Pressure ◽  
Peak Pressure ◽  
Weight Bearing ◽  
Ankle Dorsiflexion ◽  
Diabetic Foot Ulcers ◽  
Plantar Surface ◽  
Time Integral ◽  
Pressure Time ◽  
Patients With Diabetes

High plantar pressure is a risk factor for diabetic foot ulcers, and it is known that restriction of ankle dorsiflexion range of motion (ROM) causes high plantar pressure. Stretching is a non-invasive and general means to improve ROM; however, the effect of stretching on the ROM and plantar pressure has not been clarified in patients with diabetes mellitus. We aimed to study the effects of intermittent weight-bearing stretching on ankle dorsiflexion ROM and plantar pressure during gait in patients with diabetes mellitus. Seven patients with diabetes mellitus participated, and their triceps surae was stretched using weight-bearing stretching with a stretch board. Five minutes of stretching was performed 4 times with a rest interval of 30 s. Ankle dorsiflexion ROM was measured with the knee flexed and extended. Peak pressure and pressure-time integral during gait were measured and calculated for the rearfoot, midfoot, forefoot, and total plantar surface before and after stretching. Ankle dorsiflexion ROM with the knee extended or bent increased significantly after stretching ( P < .05). Peak pressure and the pressure-time integral decreased significantly, especially in the forefoot ( P < .01), and these also decreased significantly in the total plantar surface ( P < .05). The duration of foot-flat decreased after stretching ( P < .05). Weight-bearing stretching improved ankle dorsiflexion ROM and reduced plantar pressure during gait. These results suggest that weight-bearing calf stretching may be an effective means to prevent and treat diabetic foot ulcers.

The Effect of Toe Flexion Exercises on Grip

2018 ◽  
Vol 108 (5) ◽  
pp. 355-361 ◽  
Author(s):  
Helen Branthwaite ◽  
Gemma Grabtree ◽  
Nachiappan Chockalingam ◽  
Andrew Greenhalgh
Keyword(s):  
Contact Area ◽  
Plantar Pressure ◽  
Contact Time ◽  
Peak Pressure ◽  
Peak Force ◽  
Time Integral ◽  
Pressure Time ◽  
Flexor Muscles ◽  
Before And After ◽  
Force Contact

Background: Weakness of the toe flexor muscles has been attributed to the development of toe pathologies, and it responds well in the clinic to toe grip exercises. However, it is unknown whether exercising the toe flexor muscles improves the ability to grip and alter function. The aim of this study was to assess the effect of toe flexor exercises on apical plantar pressure, as a measure of grip, while seated and during gait. Methods: Twenty-three individuals with no known toe pathologies were recruited. Static peak pressure, time spent at peak pressure, and pressure-time integral while seated, as well as dynamic forefoot maximal force, contact area, and percentage contact time, were recorded before and after exercise. Toe grip exercises with a therapy ball were completed daily for 6 weeks. Results: Static peak pressure significantly increased after exercise on the apex of the second and third digits, as did the pressure-time integral. Dynamic peak force and contact area did not alter after exercise around the metatarsals and toes, yet percentage contact time significantly increased for each metatarsal after completing daily toe grip exercises. Conclusions: Exercises to improve the grip ability of the toes increased the static peak pressure on the apex of the second and third digits as well as the percentage contact time of the metatarsals during gait. The ability to increase apical peak pressure and contact time after exercises could assist in improving forefoot stability and gait efficiency and in reducing toe pathology progression.

In-Shoe Plantar Pressure Profiles in Amateur Basketball Players

2018 ◽  
Vol 108 (3) ◽  
pp. 215-224 ◽  
Author(s):  
Pui W. Kong ◽  
Wing K. Lam ◽  
Wei X. Ng ◽  
Luqman Aziz ◽  
Hin F. Leong
Keyword(s):  
Plantar Pressure ◽  
Repeated Measures ◽  
Distribution Patterns ◽  
Biomechanical Analysis ◽  
Basketball Players ◽  
Time Integral ◽  
Plantar Pressure Distribution ◽  
Pressure Profiles ◽  
Pressure Time ◽  
Injury Mechanisms

Background: Biomechanical analysis of foot loading characteristics may provide insights into the injury mechanisms and guide orthotic prescription for basketball players. This study aimed to quantify in-shoe plantar pressure profiles in amateur players when executing typical basketball movements. Methods: Twenty male university basketball players performed four basketball-specific movement tasks—running, maximal forward sprinting, maximal 45° cutting, and layup—in a pair of standardized basketball shoes fitted with an in-shoe plantar pressure measurement system. Peak pressure (PP) and pressure-time integral (PTI) data were extracted from ten plantar regions. One-way repeated-measures analysis of variance was performed across the tasks, with significance set at P &lt; .05. Results: Distinct plantar pressure distribution patterns were observed among the four movements. Compared with running, significantly higher (P &lt; .05) PP and PTI of up to approximately 55% were found in sprinting and layup, particularly at the forefoot region. Similarly, significantly higher (P &lt; .05) PPs and PTIs, ranging from approximately 23% to 90%, were observed in 45° cutting compared with running at most foot regions. Conclusions: Compared with running, sprinting and layup demonstrated higher plantar loading in the forefoot region, and 45° cutting yielded increased plantar loading in most regions of the foot. Understanding the plantar pressure characteristics of different movements may be useful in optimizing footwear designs, orthosis use, or training strategies to minimize regional plantar loading during amateur basketball play.

Prediction of Plantar Shear Stress Distribution by Artificial Intelligence Methods

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Metin Yavuz ◽  
Hasan Ocak ◽  
Vincent J. Hetherington ◽  
Brian L. Davis
Keyword(s):  
Neural Network ◽  
Shear Stress ◽  
Stress Distribution ◽  
Peak Pressure ◽  
Shear Stress Distribution ◽  
Future Research ◽  
Shear Forces ◽  
Inference System ◽  
Vertical Loading ◽  
Stress Dependent

Shear forces under the human foot are thought to be responsible for various foot pathologies such as diabetic plantar ulcers and athletic blisters. Frictional shear forces might also play a role in the metatarsalgia observed among hallux valgus (HaV) and rheumatoid arthritis (RA) patients. Due to the absence of commercial devices capable of measuring shear stress distribution, a number of linear models were developed. All of these have met with limited success. This study used nonlinear methods, specifically neural network and fuzzy logic schemes, to predict the distribution of plantar shear forces based on vertical loading parameters. In total, 73 subjects were recruited; 17 had diabetic neuropathy, 14 had HaV, 9 had RA, 11 had frequent foot blisters, and 22 were healthy. A feed-forward neural network (NN) and adaptive neurofuzzy inference system (NFIS) were built. These systems were then applied to a custom-built platform, which collected plantar pressure and shear stress data as subjects walked over the device. The inputs to both models were peak pressure, peak pressure-time integral, and time to peak pressure, and the output was peak resultant shear. Root-mean-square error (RMSE) values were calculated to test the models’ accuracy. RMSE/actual shear ratio varied between 0.27 and 0.40 for NN predictions. Similarly, NFIS estimations resulted in a 0.28–0.37 ratio for local peak values in all subject groups. On the other hand, error percentages for global peak shear values were found to be in the range 11.4–44.1. These results indicate that there is no direct relationship between pressure and shear magnitudes. Future research should aim to decrease error levels by introducing shear stress dependent variables into the models.

Biomechanical Response to External Biofeedback During Functional Tasks in Individuals With Chronic Ankle Instability

2021 ◽  
Author(s):  
Danielle M. Torp ◽  
Abbey C. Thomas ◽  
Tricia Hubbard-Turner ◽  
Luke Donovan
Keyword(s):  
Real Time ◽  
Plantar Pressure ◽  
Ankle Instability ◽  
Static Balance ◽  
Eyes Closed ◽  
Visual Biofeedback ◽  
Time Integral ◽  
Pressure Time ◽  
Eyes Open ◽  
Functional Task

Context Altered biomechanics displayed by individuals with chronic ankle instability (CAI) is a possible cause of recurring injuries and posttraumatic osteoarthritis. Current interventions are unable to modify aberrant biomechanics, leading to research efforts to determine if real-time external biofeedback can result in changes. Objective To determine the real-time effects of visual and auditory biofeedback on functional-task biomechanics in individuals with CAI. Design Crossover study. Setting Laboratory. Patients or Other Participants Nineteen physically active adults with CAI (7 men, 12 women; age = 23.95 ± 5.52 years, height = 168.87 ± 6.94 cm, mass = 74.74 ± 15.41 kg). Intervention(s) Participants randomly performed single-limb static balance, step downs, lateral hops, and forward lunges during a baseline and 2 biofeedback conditions. Visual biofeedback was given through a crossline laser secured to the dorsum of the foot. Auditory biofeedback was given through a pressure sensor placed under the lateral foot and connected to a buzzer that elicited a noise when pressure exceeded the set threshold. Cues provided during the biofeedback conditions were used to promote proper biomechanics during each task. Main Outcome Measure(s) We measured the location of center-of-pressure (COP) data points during balance with eyes open and eyes closed for each condition. Plantar pressure in the lateral column of the foot during functional tasks was extracted. Secondary outcomes of interest were COP area and velocity, time to boundary during static balance, and additional plantar-pressure measures. Results Both biofeedback conditions reduced COP in the anterolateral quadrant while increasing COP in the posteromedial quadrant of the foot during eyes-open balance. Visual biofeedback increased lateral heel pressure and the lateral heel and midfoot pressure-time integral during hops. The auditory condition produced similar changes during the eyes-closed trials. Auditory biofeedback increased heel pressure during step downs and decreased the lateral forefoot pressure-time integral during lunges. Conclusions Real-time improvements in balance strategies were observed during both external biofeedback conditions. Visual and auditory biofeedback appeared to effectively moderate different functional-task biomechanics.

CLEAR Cleat: A Proof-of-Concept Trial of an Aerobic Activity Facilitator to Reduce Plantar Forefoot Pressures and Their Potential in Those with Foot Ulcers

2008 ◽  
Vol 98 (4) ◽  
pp. 261-267 ◽  
Author(s):  
Erin E. Klein ◽  
Ryan T. Crews ◽  
Stephanie C. Wu ◽  
James S. Wrobel ◽  
David G. Armstrong
Keyword(s):  
Contact Area ◽  
Peak Pressure ◽  
Proof Of Concept ◽  
Aerobic Activity ◽  
Time Integral ◽  
Plantar Aspect ◽  
Pressure Time ◽  
The Right ◽  
Recumbent Bicycle ◽  
Healthy Participants

Background: Exercise has not been studied extensively in persons with active neuropathic diabetic foot wounds, primarily because a device does not exist that allows patients to exercise while sufficiently off-loading pressure at the ulcer site. The purpose of this project was to demonstrate a device that reduces cycling plantar forefoot pressure. Methods: Ten healthy participants rode a recumbent bicycle under three cycling conditions. While the left foot interaction remained constant with a standard gym shoe and pedal, the right foot was exposed to a control condition with standard gym shoe and pedal, gym shoe and specialized cleat, and gym shoe with an off-loading insole and specialized cleat. Pressure and contact area of the plantar aspect of the feet were recorded for a 10-sec interval once during each minute of each condition’s 7-min trial. Results: The off-loading insole and specialized cleat condition yielded significantly lower (P &lt; .01) peak pressure, contact area, and pressure–time integral values in the forefoot than the specialized cleat condition with gym shoe, which yielded significantly lower values (P &lt; .01) than the standard gym shoe and pedal. Conclusion: Modifications to footwear may alter plantar forefoot pressures, contact area, and pressure–time integrals while cycling. The CLEAR Cleat could play a significant role in the facilitation of fitness in patients with (or at high risk for) neuropathic wounds. (J Am Podiatr Med Assoc 98(4): 261–267, 2008)

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