Center of pressure and its theoretical relationship to foot pathology

1999 ◽  
Vol 89 (6) ◽  
pp. 278-291 ◽  
Author(s):  
EA Fuller
Keyword(s):  
Subtalar Joint ◽  
Center Of Pressure ◽  
Theoretical Explanation ◽  
Theoretical Relationship ◽  
Model Based ◽  
Joint Axis ◽  
Foot Function

The measurement of center of pressure has been widely used in the evaluation of foot function. This article will describe center of pressure and indicate how it can be used to calculate moments about the joint axes of the foot. Various uses of center of pressure described in the literature will be examined. A model based on the use of the location of center of pressure relative to the location of the subtalar joint axis will be proposed as a theoretical explanation of selected foot pathologies and their treatment.

Function of the Windlass Mechanism in Excessively Pronated Feet

2001 ◽  
Vol 91 (5) ◽  
pp. 245-250 ◽  
Author(s):  
Anna Aquino ◽  
Craig Payne
Keyword(s):  
Subtalar Joint ◽  
Gait Cycle ◽  
Length Ratio ◽  
Chi Square ◽  
Foot Length ◽  
Joint Axis ◽  
Visual Evidence ◽  
Foot Function ◽  
Axis Position ◽  
Chi Square Analysis

The foot postures of 39 subjects were evaluated for excessive pronation by means of six static weightbearing and five nonweightbearing measurements, and two types of footprint indexes. Visual evidence of windlass function was recorded by video. Chi-square analysis revealed that excessive pronation does not affect the establishment of the windlass mechanism. The position of the forefoot relative to the rearfoot, subtalar joint axis position, and navicular drift/foot length ratio were significantly associated with dynamic windlass function. These results suggest that selected static measurements may have value in predicting some aspects of dynamic foot function during the propulsive phase of the gait cycle. (J Am Podiatr Med Assoc 91(5): 245-250, 2001)

Position of the Subtalar Joint Axis and Resistance of the Rearfoot to Supination

2003 ◽  
Vol 93 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Craig Payne ◽  
Shannon Munteanu ◽  
Kathryn Miller
Keyword(s):  
Subtalar Joint ◽  
Sagittal Plane ◽  
Metatarsal Head ◽  
Foot Orthoses ◽  
Joint Axis ◽  
Foot Function ◽  
Two Parameters ◽  
The Relationship ◽  
Clinical Determination

Determination of the position of the subtalar joint axis is being more widely used clinically to facilitate the prescription of foot orthoses and the understanding of foot function, but clinical determination of the axis has not been widely investigated. The aim of this study was to determine the relationship between clinical determination of the subtalar joint axis and the amount of force needed to supinate the foot. The transverse plane position of the subtalar joint axis was determined in 47 subjects. The sagittal plane orientation of the subtalar joint axis was determined using the relative amounts of forefoot adduction and abduction obtained when the rearfoot was supinated and pronated. The amount of force needed to supinate the foot was measured using a device designed to measure resistance to supination. The only two parameters that were correlated to supination resistance of the rearfoot were body weight (r = 0.52) and the perpendicular distance from the fifth metatarsal head to the subtalar joint axis (r = 0.59). The model on which determination of the subtalar joint axis is based may not be valid, but it might help determine how much force is needed to supinate a foot using foot orthoses. (J Am Podiatr Med Assoc 93(2): 131-135, 2003)

Subtalar Joint Axis Location and Rotational Equilibrium Theory of Foot Function

2001 ◽  
Vol 91 (9) ◽  
pp. 465-487 ◽  
Author(s):  
Kevin A. Kirby
Keyword(s):  
Lower Extremity ◽  
Subtalar Joint ◽  
Reaction Force ◽  
Spatial Location ◽  
Joint Axis ◽  
Tensile Forces ◽  
Clinical Consequences ◽  
Rotational Equilibrium ◽  
Foot Function ◽  
Biomechanical Effect

A new theory of foot function based on the spatial location of the subtalar joint axis in relation to the weightbearing structures of the plantar foot is proposed. The theory relies on the concept of subtalar joint rotational equilibrium to explain how externally generated forces, such as ground reaction force, and internally generated forces, such as ligamentous and tendon tensile forces and joint compression forces, affect the mechanical behavior of the foot and lower extremity. The biomechanical effect of variations among individuals in the spatial location of the subtalar joint axis are explored, along with their clinical consequences, to offer an additional theory of foot function, which may improve on existing podiatric biomechanics theory. (J Am Podiatr Med Assoc 91(9): 465-487, 2001)

The Subtalar Joint Axis Locator

2006 ◽  
Vol 96 (3) ◽  
pp. 212-219 ◽  
Author(s):  
Simon K. Spooner ◽  
Kevin A. Kirby
Keyword(s):  
Subtalar Joint ◽  
Dynamic Capabilities ◽  
Three Dimensional ◽  
Spatial Location ◽  
Exit Point ◽  
Neck Position ◽  
Dorsal Aspect ◽  
Joint Axis ◽  
Preliminary Study ◽  
Rotational Motions

A new clinical device, the subtalar joint axis locator, was created to track the three-dimensional location of the subtalar joint axis during weightbearing movements of the foot. The assumption was that if the anterior exit point of the subtalar joint axis is stationary relative to the dorsal aspect of the talar neck, then, by performing radiographs of the feet with the subtalar joint axis locator in place on the foot, the ability of the locator to track rotations and translations of the talar neck and thus the subtalar joint axis in space could be approximated. In this preliminary study of two adults, the subtalar joint axis locator accurately tracked the talar neck position during weightbearing rotational motions of the subtalar joint. The device was also used in a series of subjects to determine its dynamic capabilities. It is possible, then, that the subtalar joint axis locator can reliably track the spatial location of the subtalar joint axis during weightbearing movements of the foot. (J Am Podiatr Med Assoc 96(3): 212–219, 2006)

scholarly journals Postural control learning dynamics in Parkinson’s disease: early ‎improvement with plateau in stability, and continuous progression in ‎flexibility and mobility

2020 ◽  
Author(s):  
Zahra Rahmati ◽  
Saeed Behzadipour ◽  
Alfred C. Schouten ◽  
Ghorban Taghizadeh ◽  
Keikhosrow Firoozbakhsh
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Postural Control ◽  
Training Program ◽  
Center Of Pressure ◽  
Balance Training ◽  
Patient Specific ◽  
Learning Dynamics ◽  
Early Improvement ◽  
Model Based

Abstract Background: Balance training improves postural control in Parkinson’s disease (PD). However, a systematic approach for the development of individualized, optimal training programs is still lacking, as the learning dynamics of the postural control in PD, over a training program are poorly understood. Objectives: We investigated the learning dynamics of the postural control in PD, during a balance-training program, in terms of the clinical, posturographic, and novel model-based measures. Methods: Twenty patients with PD participated in a balance-training program, 3 days a week, for 6 weeks. Clinical tests assessed functional balance and mobility pre-training, mid-training, and post-training. Center-of-pressure (COP) was recorded at four time-points during the training (pre-, week 2, week 4, and post-training). COP was used to calculate the sway measures and to identify the parameters of a patient-specific postural control model, at each time-point. The posturographic and model-based measures constituted the two sets of stability- and flexibility-related measures. Results: Mobility- and flexibility-related measures showed a continuous improvement during the balance-training program. In particular, mobility improved at mid-training and continued to improve to the end of the training, whereas flexibility-related measures reached significance only at the end. The progression in the balance- and stability-related measures was characterized by early improvements over the first three to four weeks of training, and reached a plateau for the rest of the training. Conclusions: The progression in balance and postural stability is achieved earlier and susceptible to plateau out, while mobility and flexibility continues to improve during the balance training.

The medial heel skive technique. Improving pronation control in foot orthoses

1992 ◽  
Vol 82 (4) ◽  
pp. 177-188 ◽  
Author(s):  
KA Kirby
Keyword(s):  
Subtalar Joint ◽  
New Method ◽  
Foot Orthoses ◽  
Posterior Tibial ◽  
Joint Axis ◽  
Flat Feet ◽  
Foot Orthosis

A new method of foot orthosis modification that enhances the pronation controlling ability of foot orthoses is presented. The medial heel skive technique involves selectively removing small amounts of the medial portion of the plantar heel of the positive cast of the foot to create a unique varus wedging effect within the heel cup of the foot orthosis. The resulting increase in supination moment across the subtalar joint axis of the foot clinically produces significantly improved pronation control on pediatric flexible flat feet, posterior tibial dysfunction, and other types of excessively pronated feet.

Subtalar Joint Axis in Patients With Symptomatic Peritalar Subluxation Compared to Normal Controls

2014 ◽  
Vol 35 (11) ◽  
pp. 1153-1158 ◽  
Author(s):  
Kelly L. Apostle ◽  
Nathan W. Coleman ◽  
Bruce J. Sangeorzan
Keyword(s):  
Subtalar Joint ◽  
Joint Axis ◽  
Normal Controls

scholarly journals Effects of the degree of freedom and assistance characteristics of powered ankle-foot orthoses on gait stability

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242000
Author(s):  
Ho Seon Choi ◽  
Yoon Su Baek
Keyword(s):  
Subtalar Joint ◽  
Center Of Pressure ◽  
Pearson Correlation ◽  
Critical Role ◽  
Angular Acceleration ◽  
Degree Of Freedom ◽  
Measurement Unit ◽  
Foot Orthoses ◽  
Gait Stability ◽  
Ankle Foot Orthoses

We studied the use of powered ankle-foot orthoses (PAFOs) and walking stability of the wearers, focusing on the ankle joint, which is known to play a critical role in gait stability. Recognizing that the subtalar joint is an important modulator of walking stability, we conducted the walking experiment on a treadmill by applying varying assistance techniques to the 2-degree-of-freedom (DOF) PAFO, which has the subtalar joint as the rotating axis, and the commonly used 1-DOF PAFO. The participants were 8 healthy men (mean±SD: height, 174.8±7.1 cm; weight, 69.8±6.5 kg; and age, 29.1±4.8 years) with no history of gait abnormality. Center of pressure (COP) was measured with an in-shoe pressure sensor, and stability was estimated on the basis of the angular acceleration measured with the inertial measurement unit attached to the trunk. The experimental results of the 2-DOF PAFO, with or without assistance, showed a significantly higher stability than those of the 1-DOF PAFO (up to 23.78%, p<0.0326). With the 1-DOF PAFO, the stability deteriorated with the increase in the degree of assistance provided. With the 2-DOF PAFO, this tendency was not observed. Thus, the importance of the subtalar joint was proven using PAFOs. The mean position analysis of the COP during the stance phase confirmed that the COP highly correlated with stability (Pearson correlation coefficient: −0.6607). Thus, we conclude that only the 2-DOF PAFO can maintain walking stability, regardless of the assistance characteristics, by preserving the COP in the medial position through eversion. Awareness regarding the role of the subtalar joint is necessary during the manufacture or use of PAFOs, as lack of awareness could lead to the degradation of the wearer’s gait stability, regardless of effective assistance, and deteriorate the fundamental functionality of PAFO.

scholarly journals Postural control learning dynamics in Parkinson’s disease: early ‎improvement with plateau in stability, and continuous progression in ‎flexibility and mobility

2020 ◽  
Author(s):  
Zahra Rahmati ◽  
Saeed Behzadipour ◽  
Alfred C. Schouten ◽  
Ghorban Taghizadeh ◽  
Keikhosrow Firoozbakhsh
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Postural Control ◽  
Training Program ◽  
Center Of Pressure ◽  
Balance Training ◽  
Patient Specific ◽  
Learning Dynamics ◽  
Early Improvement ◽  
Model Based

Abstract Background: Balance training improves postural control in Parkinson’s disease (PD). However, a systematic approach for the development of individualized, optimal training programs is still lacking, as the learning dynamics of the postural control in PD, over a training program are poorly understood.Methods: We explored the learning dynamics of the postural control in PD, during a balance-training program, in terms of the clinical, posturographic, and model-based measures. Twenty patients with PD participated in a balance-training program, 3 days a week, for 6 weeks. Clinical tests assessed functional balance and mobility pre-training, mid-training, and post-training. Center-of-pressure (COP) was recorded at four time-points during the training (pre-, week 2, week 4, and post-training). COP was used to calculate the sway measures and to identify the parameters of a patient-specific postural control model, at each time-point (stability and flexibility degree). The posturographic and model-based measures constituted the two sets of stability- and flexibility-related measures.Results: Mobility- and flexibility-related measures showed a continuous improvement during the balance-training program. In particular, mobility improved at mid-training and continued to improve to the end of the training, whereas flexibility-related measures reached significance only at the end. The progression in the balance- and stability-related measures was characterized by early improvements over the first three to four weeks of training, and reached a plateau for the rest of the training. Conclusions: The progression in balance and postural stability is achieved earlier and susceptible to plateau out, while mobility and flexibility continues to improve during balance training.

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