The Critical Analysis Of The Paradigms Associated With Normal Human Gait

The Critical Analysis of the Paradigms associated with Normal Human Gait
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Introduction
The human foot is a complex structure consisting of bones, joints, ligaments, tendons, intrinsic, extrinsic muscles, nerves, and blood vessels, all playing a crucial role in the biomechanical function of the lower limb. These components of the foot structure provide the foundation of support while one is standing, walking, and running. The foot behaves like a spring by storing and releasing energy by use of the extrinsic and intrinsic muscles in the arch (McKeon, Hertel, Bramble and Davis, 2014). According to McKeon, Hertel, Bramble and Davis (2014), arch stability is a core element for the effective and efficient functioning of the foot. In addition, according to Petcu Daniel and Anca Colda (2012), the foundation of gait analysis study is based on the proposed paradigms of foot function by the association between the function of anatomical segments considered and the relevant structure.
According to Daniel and Colda (2012), the most recognised paradigms are the Neutral Position of the Subtalar Joint developed by Merton Root, Sagittal Plane Facilitation Theory developed by Haward Dananberg, Tissue Stress Theory developed by McPoil and Hunt (1995), and Neuromechanical theory developed by Benno Nigg. The modelling of lower limb biomechanics is initiated by clinical reflection on the gait followed by gait analysis, kinetic and kinematic intricacy using multiple sets and models (Daniel, Colda, 2012). Daniel and Colda (2012) suggest that podiatrists need to understand the structure of the foot and the kinetics and kinematics of normal human gait. This enables them to assess, diagnose and treat any medical conditions of the foot, ankle and lower extremity. This essay will critically analyse the different methods of gait analysis and paradigms in a chronological manner associated with normal human gait starting with the Root’s paradigm to the most recent theories. These paradigms will also be compared and contrasted critically for the better understanding of podiatrists under the normal functioning of the foot and ankle. The first area of discussion is Gait analysis.
Gait Analysis
Human gait can be defined literally as locomotion that comes as a result of movement of human limbs. Human beings possess the ability to walk upright on two legs or rather referred to as bipedalism (Arundhati G Thakurta, Rauf Iqbal, Shreya Maulik, 2016). According to Thakuta, Igbal, and Maulik (2016), alternating movements of sinuous of different sections of the body occur during the gait process. Differences in movement patterns of limbs, general velocity, varied forces, energy in motion and potential energy and also variations in surface contact characterise the various gait patterns (Thakuta et al., 2016). Studies indicate that there are changes in the activities of muscles with a variation of gait pattern in varying situations. Thakuta et al (2016) further suggest that there are various categories of human gaits such as natural and trained gaits. Besides, human beings use the natural gaits instinctively such as normal walking on feet and running while trained gaits are acquired and are non-instinctive such hand walking. In addition, the walking process varies among individuals and due to different environmental conditions. For instance, in an investigation by Tommy Oberg, Alek Karsznia and Kurt Oberg (1993), the results indicate that gait velocity and step length was lower and step frequency was higher in women more than men. We have different measures of gait referred to as temporal-spatial parameters that constitute speed of walking, length and time of a stride, length and time of a step, phases of stances and swings (Thakurta et al., 2016).
The gait analysis is commonly undertaken by observation to characterise the gait pathologies. Ross Bogey (2016) in his writing about Gait Analysis notes that observational gait approach is enough to realize any abnormalities in patterns of walking. However, objective analysis is introduced as the complexity of walking increases with organic pathology. Other parameters of gait analysis may follow either individually or collectively. Some factors such as clinical need, considerations of finance and laboratory staffing determine the choice of gait analysis. Bogey (2016) notes that gait can be analysed by observing the instrumental motion of the foot. Most of the gait movement happens in the sagittal plane but the process of measuring human motion is very complex since subtle rotations experienced in other planes are crucial clinically (Ross Bogey, 2016). The observational method of gait analysis fails to be effective when clinical operations have to consider subtle rotations. This may necessitate the application of other advanced methods as an alternative to foot motion observation.
Bogey (2016) further indicates that three-dimensional analysis of motion has assisted to overcome challenges of observing complex movements in the foot. In this technique, markers are placed on the skin surface to estimate the position of centres of rotation then recording of limb segment motion if carried out. In this approach, at least three markers are placed on each limb segment and their positions recorded by the use of multiple cameras. A system of calibration works to translate film to real-life dimensions. In addition, the angular position of every segment may be identified for each percent gait cycle interval. Mathematical differentiation and smoothing of the data for limb position help to obtain the angular velocity and acceleration (Bogey, 2016). Bogey (2016) gives an alternative approach of using electro-goniometers. The sagittal, coronal, and transverse planes are recorded by the use of triaxle electro-goniometer that has parallelograms and potentiometers. Electro-goniometers have the advantages of ease to use, instant availability of data and reduction in expenses as compared to acquisition techniques of video (Ross Bogey, 2016).
Nester et al (2011) propose another technique of using external forces that affect the body in gait analysis. The calculation of moments of joints and forces of reaction between different segments depends on the available information about inertia components of specific kinematics, parameters of body segments and also external forces also referred to as kinetics. According to Nester et al (2011), Cadaveric data also called modelling of limb segments mathematically contain the various magnitude and distribution of masses of segments with respect to the axes of joints. A force platform measures ground reaction also called the ground contact force that is used at the distal segment. The force platform measures forces and moments in three different dimensions based on the pressure at the centre of the foot. Oscillations of the pressure centre can also be determined in a similar manner (Nester et al., 2011)
In the writing of Bogey (2016) moments and power are also used in the analysis of gait. Information about moments and the power of joints and the reaction forces that occur between segments can be obtained by integrating the external forces, pressure centre different specific segment parameters of the body and data of motion. The magnitude, sign of moments and power introduces the various important roles of muscle groups.
The gait analysis processes have played significant roles in the provision of information that rectified surgical planning. However, some of the advanced methods of gait analysis are not fully effective and safe to human beings. Chris Bishop, Dominic Thewlis and Gunther Paul (2012) say that a model must remain clear to its purpose and what it actually represent. However, the complexity of the marker set and the model used should always be indicative of the analytical question complexity as well as the number of individual segments under analysis (Bishop et al, 2012). Bjorn Lofterod, Terje Terjesen and Ingrid Skaaret (2006) suggest that preoperative gait analysis has significant impacts on orthopedic decision making in children with cerebral palsy. The debate on the role of gait analysis gives evidence of a process that is not very effective. Lofterod et al (2006) state that gait analysis has the ability to alter surgical plans to about half of the patients. In a research by Kay et al (2000), treatment plans for 42 patients among the 60 selected were altered after gait analysis. More than half number of patients under study had altered treatment plan as a result of gait analysis (Lofterod et al., 2006). Such a figure is very significant to conclude that gait analysis process are not effective to patients and clinicians should not over-rely on them. Closely related to gait analysis is the assessment of lower limb function.
Assessment of Lower Limb function
In the writings of Patrick McKeon, Jay Hertel, Dennis Bramble and Irene Davis (2014), clinical assessment of intrinsic foot muscles has received little attention from clinicians. Only certain conditions of diabetic neuropathy and claw toes give attention to the functioning of foot muscles. McKeon et al (2014) further state that assessment of lower limb function is mostly related to reduced strength of toe flexion or atrophy of the intrinsic foot muscles. The assessment techniques of lower limb function are classified as either direct or indirect. The direct technique of evaluation focusses more on assessing the strength of toe flexion while the indirect approach involves techniques of taking images and EMG in the estimation of the intrinsic foot muscle (McKeon et al, 2014).
According to McKeon et al (2014), testing of the intrinsic foot muscle involves various procedures. The clinician sets the foot test of a patient in neutral position of the subtalar with the calcaneus and heads of metatarsal on the ground. The patient brings down their toes to the ground and maintains the position of the foot in a single stance for about 30 minutes. The clinician is then keen to observe gross changes that might appear in height of navicular and also over-activity of extrinsic muscles (McKeon et al, 2014). Testing with indirect approach involves the use of real-time ultrasound imagining that guides and confirms the position of the indwelling electrode. McKeon et al (2014) further state that there is an ability to assess activation of abductor hallucins, flexor digitorum brevis, quadratus and even the dorsal interossei.
However, these techniques have many limitations that make them ineffective. MaKeon et al (2014) note that direct technique of assessment has the limitation of not being able to distinguish contributions of both intrinsic and extrinsic toe flexor muscles. The direct approach of assessment includes muscle testing manually, the dynamometry of toe grip, pedobarograph and paper grip paired with intrinsic positive tests (McKeon et al, 2014). McKeon et al (2014) state that these approaches largely ignore proximal functions of intrinsic muscles in support of foot arches. However, they emphasize strictly on roles of the muscles in toe flexion production. The approach fails to be effective since proximal functions in supporting foot arches are more significant than just producing the flexion. Besides, McKeon et al, 2014 notes that the indirect approach of assessment are largely used in laboratories instead of clinics where their application is more significant. Consequently, there are no clinical studies to prove the use of both surface wire and EMG in the assessment of the functioning of plantar intrinsic muscle. These facts based on researchers imply that the techniques of assessing lower limb function are not fully reliable. They still contain significant limitations for use in clinical settings. According to Oberg et al (1993), gait analysis should always be interpreted with regard to a thoroughly defined test situation. In another investigation by Andrew Bult, George Murley, Paul Butterworth, Pazit Levinger and Hylton Menz (2013) they found out that individuals with planus display increased the motion of the lower limb during walking. Furthermore, Bult et al (2013) suggest that there is evidence of an association between planus foot posture and increased frontal plane motion of the rearfoot. However, the findings lack validity and certainty for use in clinical settings. This, therefore, calls for more research on the relationship between the foot posture and lower limb kinematics. After analysis of gait process, the next area of focus is the different paradigms associated with the human foot functioning (Bult et al, 2013)
Critical analysis of the paradigms
The various theories or rather concepts that scientists have developed over a period of time to understand the gait process are referred to as paradigms. Thomas Kuhn (2012) in his writings about Second Thoughts on Paradigms describes a paradigm as things that only members of a scientific community share. Some scholars believe paradigms range from scientific achievements in concrete form to some set of beliefs and preconceptions about a certain idea. Generally, the sense of paradigm globally is the ability to embrace the commitments shared by scientific groups (Thomas Kuhn, 2012). According to Petcu Daniel and Anca Colda (2012), different concepts describe the normal human gait processes. Various scientists developed these concepts to assist medical professions orthopedics, medical rehabilitation, and physiotherapy or rather podiatry. It has, therefore, been possible to document prescription of functional diabetic foot treatment. However, these concepts have limitations that attract criticism from other scientists. According to Stephen F Albert (2014), the many paradigms on foot functioning and treatment of mechanically induced problems of the foot have been presented as facts and not just theories (Stephen F Albert, 2014). Being presented as theories can enable questioning of some factors and development of other scientific improvements.
The Neutral Position of the Subtalar joint
The first paradigm called the Neutral Position of the Subtalar joint was introduced by Merton Root and other coworkers between the year 1971 and 1978 in the United States of America. According to Daniel and Colda (2012) Root set a reference system that was unified and resulted in the development of other paradigms. This paradigm developed as a reference system for classifying structural anomalies in foot functioning. The scientific results by leading researchers such as Inman, Elftman, Hicks and Write influenced Root to develop the system. The researchers had the objective of identifying the position of axes of motion for the joints of feet and especially the subtalar joint. In addition, they were interested in describing the working mechanisms of various anatomical structures, assessing the activities of muscles, and dynamic behaviour of the foot during the process of gait (Daniel and Colda, 2012). Various factors influenced Root to develop the first theory of human gait. They included the experience on the job and also other scientists around him.
In regards to his clinical experience and also the results of the research papers by other scientists, Root introduced the concept of a neutral subtalar joint position that was described as the subtalar joint position when the foot is neither in pronation nor supination (Daniel and Colda, 2012). According to clinical observations, there is about a two to one ratio between the movements of inversion and eversion in the rear foot when compared to the neutral position. This unique definition, therefore, allows identification and measurement of structural deformities using clinical examinations hence enabling comparison of assessments with other clinicians. Due to many limitations associated with Root’s theory, there was increased criticism and even development of other paradigms which were to serve as alternatives.
Criticism of Root’s paradigm
Hannah Jarvis (2013) notes that, biomechanical examinations of foot suggested by Root et al (1971, 1977) receives critical appraisal due to the concepts such as examination of the frontal plane angle of the subtalar joint in NCSP and RCSP, limb length examination, examination and examination of the frontal plane range at the subtalar joint. Further concepts of criticism include an examination of the forefoot to rearfoot relationship, examination of the sagittal plane position mobility of the first ray and finally an examination of the range of dorsiflexion at the first metatarsophalangeal joint (Jarvis, 2013).
The model developed by Root based on the argument that bones and joints in a normal foot indicate certain specific alignments and different motion ranges which can be measured by static biomechanical assessment. Besides, abnor...