No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Identification of pronation-supination patterns on runners: An aplication of functional principal component analysis
Abstract
The correct classification of runners according to their gait patterns is a relevant issue for the design of sports footwear. Specifically, the classification of runners as neutral, pronators, and supinators is a problem that is not yet fully solved, and requires expert observation, since current models based on the automatic processing of kinematic measures are very limited. This work proposes a method based on Functional Data Analysis (FDA) for automatically describing the morphology of the curves that represent ankle movement patterns. By Functional Analysis of Principal Components, the information contained in each data stream is reduced to a small set of variables, that allows an efficient classification of subjects.
ResearchGate has not been able to resolve any citations for this publication.
This paper presents an application of functional principal component analysis (FPCA) to describe the inter-subject variability
of multiple waveforms. This technique was applied to the study of sit-to-stand movement in two groups of people, osteoarthritic
patients and healthy subjects. Although STS movement has not been extensively applied to the study of knee osteoarthritis,
it can provide relevant information about the effect of osteoarthritis on knee joint function. Two waveforms, knee flexion
angle and flexion moment, were analysed simultaneously. Instead of using the common multivariate approach we used the functional
one, which allows working with continuous functions with neither discretization nor time-scale normalization. The results
show that time-scale normalization can alter the FPCA solution. Furthermore, FPCA presents better discriminatory power compared
with the classical multivariate approach. This technique can, therefore, be applied as a functional assessment tool, allowing
the identification of relevant variables to discriminate heterogeneous groups such as healthy and pathological subjects.
In spite of some significant progress in the understanding of the biomechanics of the ankle joint complex, especially the coupling mechanism between foot and leg, various mechanisms causing overuse injuries in the lower extremities are still poorly understood. Some increased pronation of the foot is often physiological, but excessive pronation is potentially harmful. Compensatory overpronation may occur for anatomical reasons. However, not only the amount of foot eversion, but also the way this eversion is transferred into tibial rotation may be crucial to the overloading stress on the knee. In other words, the individual transfer mechanism of foot eversion into internal tibial rotation may be of some predictable value for lower extremity overloading and related injuries. Further research is necessary to improve the functional understanding of anatomical and biomechanical abnormalities and their pathological value in predicting overuse injuries.
In spite of some significant progress in the understanding of the biomechanics of the ankle joint complex, especially the coupling mechanism between foot and leg, various mechanisms causing overuse injuries in the lower extremities are still poorly understood. Some increased pronation of the foot is often physiological, but excessive pronation is potentially harmful. Compensatory overpronation may occur for anatomical reasons. However, not only the amount of foot eversion, but also the way this eversion is transferred into tibial rotation may be crucial to the overloading stress on the knee. In other words, the individual transfer mechanism of foot eversion into internal tibial rotation may be of some predictable value for lower extremity overloading and related injuries.
Further research is necessary to improve the functional understanding of anatomical and biomechanical abnormalities and their pathological value in predicting overuse injuries.
Objectives: Excessive foot pronation and fatigue in running are possible risk factors for injuries. Motion control footwear was designed to limit excessive foot motion in runners, but its clinical efficacy has not been well reported. This study investigated the rearfoot kinematics in runners when running with different footwear before and after fatigue of the lower leg muscles. Design: Within subjects repeated measures. Setting: University gait laboratory. Participants: 25 female recreational runners. Main outcome measures: A Vicon three-dimensional motion analysis system was used to capture the rearfoot motions of 25 recreational runners who had excessive foot pronation, when running with motion control shoes and neutral shoes before and after fatigue of the lower leg muscles. Results: The findings with neutral shoe testing revealed a significant increase in rearfoot angle of 6.5° (95% CI 4.7-8.2°) (p<0.01) when the muscles were fatigued. However, the findings with motion control shoes revealed that rearfoot angle was marginally insignificant (p=0.06) in subjects before and after muscle fatigue. Moreover, rearfoot motion when running with neutral shoes was higher than that with motion control shoes in both pre- (p<0.01) and post-fatigue states (p<0.01). Conclusions: Motion control shoes can control excessive rearfoot movements in runners with over-pronation regardless of the state of leg muscle fatigue.
The Standardization and Terminology Committee (STC) of the International Society of Biomechanics (ISB) proposes a general reporting standard for joint kinematics based on the Joint Coordinate System (JCS), first proposed by Grood and Suntay for the knee joint in 1983 (J. Biomech. Eng. 105 (1983) 136). There is currently a lack of standard for reporting joint motion in the field of biomechanics for human movement, and the JCS as proposed by Grood and Suntay has the advantage of reporting joint motions in clinically relevant terms.In this communication, the STC proposes definitions of JCS for the ankle, hip, and spine. Definitions for other joints (such as shoulder, elbow, hand and wrist, temporomandibular joint (TMJ), and whole body) will be reported in later parts of the series. The STC is publishing these recommendations so as to encourage their use, to stimulate feedback and discussion, and to facilitate further revisions.For each joint, a standard for the local axis system in each articulating bone is generated. These axes then standardize the JCS. Adopting these standards will lead to better communication among researchers and clinicians.
Multivariate data analysis permits the study of observations which are finite sets of numbers, but modern data collection situations can involve data, or the processes giving rise to them, which are functions. Functional data analysis involves infinite dimensional processes and/or data. The paper shows how the theory of L-splines can support generalizations of linear modelling and principal components analysis to samples drawn from random functions. Spline smoothing rests on a partition of a function space into two orthogonal subspaces, one of which contains the obvious or structural components of variation among a set of observed functions, and the other of which contains residual components. This partitioning is achieved through the use of a linear differential operator, and we show how the theory of polynomial splines can be applied more generally with an arbitrary operator and associated boundary constraints. These data analysis tools are illustrated by a study of variation in temperature-precipitation patterns among some Canadian weather-stations.
This paper presents a vector method for measuring rigid body motion from marker coordinates, including both finite and infinitesimal displacement analyses. The common approach to solving the finite displacement problem involves the determination of a rotation matrix, which leads to a nonlinear problem. On the contrary, infinitesimal displacement analysis is a linear problem that can be easily solved. In this paper we take advantage of the linearity of infinitesimal displacement analysis to formulate the equations of finite displacements as a generalization of Rodrigues’ formula when more than three points are used. First, for solving the velocity problem, we propose a simple method based on a mechanical analogy that uses the equations that relate linear and angular momenta to linear and angular velocities, respectively. This approach leads to explicit linear expressions for infinitesimal displacement analysis. These linear equations can be generalized for the study of finite displacements by using an intermediate body whose points are the midpoint of each pair of homologous points at the initial and final positions. This kind of transformation turns the field of finite displacements into a skew-symmetric field that satisfies the same equations obtained for the velocity analysis. Then, simple closed-form expressions for the angular displacement, translation, and position of finite screw axis are presented. Finally, we analyze the relationship between finite and infinitesimal displacements, and propose vector closed-form expressions based on derivatives or integrals, respectively. These equations allow us to make one of both analyses and to obtain the other by means of integration or differentiation. An experiment is presented in order to demonstrate the usefulness of this method. The results show that the use of a set of markers with redundant information (n>3) allows a good accuracy of measurement of kinematic variables.
When either data or the models for them involve functions, and when only weak assumptions about these functions such as smoothness are permitted, familiar statistical methods must be modified and new approaches developed in order to take advantage of this smoothness. The first part of the article considers some general issues such as characteristics of functional data, uses of derivatives in functional modelling, estimation of phase variation by the alignment or registration of curve features, the nature of error, and so forth. The second section describes functional versions of traditional methods such principal components analysis and linear modelling, and also mentions purely functional approaches that involve working with and estimating differential equations in the functional data analysis process.
Casted and plate orthoses were compared for their effectiveness in controlling excessive pronation and providing associated symptom relief. Two subject groups (n=30) matched for sex, age, sport involvement and injury type were prescribed either a casted or plate orthosis and were evaluated over a 3 month period. Pronation during treadmill running trials, with and without orthotic intervention, was determined by using two-dimentional video analysis. Symptom improvement was evaluated via questionnaire analysis. Two way analysis of variance demonstrated that both types of orthosis effectively reduced total pronation, maximum velocity of pronation, total calcaneal eversion and maximum velocity of calcaneal eversion (P<0.05), with no significant difference between orthotic types. Questionnaire analysis indicated that symptoms improved (to some extent) in 92% of all subjects after one month, with little difference between orthotic type. Considering the cost difference of the two types of orthotics (casted costing 2.5 times more), plate orthoses provide satisfactory treatment.
To quantify the effects of medial foot orthoses on skeletal movements of the calcaneus and tibia during the stance phase in running.
Kinematic effects of medial foot orthoses (anterior, posterior, no support) were tested using skeletal (and shoe) markers at the calcaneus and tibia.
Previous studies using shoe and skin markers concluded that medially placed orthoses control/reduce foot eversion and tibial rotation. However, it is currently unknown if such orthoses also affect skeletal motion at the lower extremities.
Intracortical Hofman pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Eversion (skeletal and shoe) and tibial rotation were calculated to study the foot orthoses effects.
Orthotic effects on eversion and tibial rotations were found to be small and unsystematic over all subjects. Differences between the subjects were significantly larger (p<0.01; up to 10 degrees ) than between the orthotic conditions (1-4 degrees ). Significant orthotic effects across subjects were found only for total internal tibial rotation; p<0.05).
This in vivo study showed that medially placed foot orthoses did not change tibiocalcaneal movement patterns substantially during the stance phase of running.
Orthoses may have only small kinematic effects on the calcaneus and tibia (measured with bone pins) as well as on the shoes (measured with shoe markers) during running of normal subjects. Present results showed that orthotic effects were subject specific and unsystematic across conditions. It is speculated that orthotic effects during the stance phase of running may be mechanical as well as proprioceptive.
OBJECTIVE: The purpose of this research was to compare the three-dimensional kinematics of runners exhibiting excessive rearfoot pronation with those having normal rearfoot pronation. DESIGN: The study design was a comparative investigation of two types of running patterns. BACKGROUND: Excessive rearfoot pronation is often linked with overuse injuries of the lower extremity. However, the literature is void of papers describing the rearfoot motion of runners presenting with excessive rearfoot pronation. Many knee-related injuries in runners are associated with increased rearfoot pronation; however, knee mechanics in this population of runners have yet to be studied. Finally, three-dimensional studies are needed to describe joint motion fully during running and these are also lacking. METHODS: Eighteen subjects (nine excessive pronators -- PRs; nine normals -- NLs) were studied during treadmill running at 3.35 m/s. Retroreflective markers were placed on the foot, shank and thigh segments and recorded with four 200 Hz video cameras. Three-dimensional kinematics were computed. RESULTS: A downward shift of the eversion curve was seen in the PR group resulting in an everted position of the rearfoot at both footstrike and toe-off compared with an inverted posture seen in the NL group. The amount of toe-out was not significantly different between the two groups. At the knee, the PR group demonstrated significantly less adduction and significantly greater flexion than the NL. Mean peak velocities of the PR group were greater in all angular measures except knee adduction. However, only foot dorsiflexion and eversion and knee flexion velocities were significantly different. CONCLUSIONS: Kinematic differences were noted at both the rearfoot and the knee of the runners who exhibit excessive rearfoot pronation.
Pronation of the foot is believed to be one of the mechanisms used during locomotion to attenuate the loading experienced by the body at ground contact. The purpose of this study was to quantify the changes in loading induced by modifications to the normal pronation of the foot during walking and running. Impact loading in 10 subjects was determined using ground reaction force and tibial acceleration. The results indicated that impact loading was increased when normal pronation was prevented during running. However, there was no reduction in impact loading when normal pronation was exaggerated. RELEVANCE: Orthotic corrections are commonly prescribed to control excessive foot pronation in patients who experience knee pain. The findings of the present paper demonstrate that pronation modifications can affect the magnitude of the impact experienced by the body during locomotion. It was also found that the loading responses to pronation modifications were not consistent between walking and running. Thus care should be exercised when orthotics that will be used for both walking and running are prescribed. Furthermore, patients should be informed that their orthotics may be activity specific.
The purpose of this study was to establish the effect of simple non moulded flat based insoles on three-dimensional foot motion during normal walking. Excessive foot pronation is considered a major contributing factor to lower limb injuries. Moulded foot orthoses have been shown to decrease maximum foot eversion. Simple insoles are widely used in clinical practice as an alternative to moulded orthoses. However, there has been little research into the kinematic effects of simple insoles.
All subjects had an inverted rearfoot and forefoot position when the subtalar joint was placed in neutral, which was assessed by a weight bearing goniometer. Rotations of the whole foot about three orthogonal axes relative to the shank were estimated using a five camera motion analysis system.
Biplanar insoles significantly (P < 0.05) reduced maximum eversion by an average of 3.1 degrees when compared to the no insole condition. The cobra insole reduced maximum eversion by an average of 2.1 degrees when compared to the no insole condition. This difference approached statistical significance (P = 0.058).
Biplanar and cobra insoles had no significant effect on maximum dorsiflexion, abduction or rate of eversion, when compared to the no insole condition. These results provide some limited support for the use of simple insoles to control for excessive foot pronation during walking.
Physiology of the joints. The lower limb
- I A Kapandji
Kapandji, I. A. (1987). Physiology of the joints. The lower
limb. Churchill Livingstone Ed.
Do pronators pronate?
- D J Stefanyshyn
- P Stergiou
- B M Nigg
Stefanyshyn DJ, Stergiou P, Nigg BM, et al. (2003). Do
pronators pronate? 6th Symposium on Footwear
Biomechanics, Queenstown, New Zealand, July 2003.