gait and posture evaluation in rehabilitation

Engineering Faculty

University of Porto

Monograph

Gait and Posture Evaluation in Rehabilitation

Andreia Filipa Fonseca da Silva

Integrated Master Degree on Bioengineering Biomedical Engineering

Porto, February 2011

Gait and posture evaluation in rehabilitation

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“The natural condition of the bodies is not the rest, but the movement” Galileu


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Engineering Faculty

University of Porto

Monograph

Gait and Posture Evaluation in Rehabilitation

Supervisor:

Professor João Manuel R. S. Tavares

Mechanical Engineering Department

Engineering Faculty

University of Porto

Co-supervisor:

MSc Andreia Sousa

School of Health Technology of Porto

Polytechnic Institute of Porto

Porto, February 2011


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Acknowledgments

I would like to thank Professor João Manuel R. S. Tavares, the availability and

support granted for this work.

I would also like to thank the availability and help given by Andreia Sousa during this work.

Finally, I would like to thank Professor Artur Cardoso, for all patience and availability to answer our questions and concerns.


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Abstract

Walking is one of the most important functions of Human Being, and the most elementary form of moving. No other movement realized by Men is performed as often and as automatically as walking. It is a complex interaction of joint movements, selectively controlled muscle activity and positional perception which allow a person to move within a chosen speed and direction.

However, since ever it is possible to see problems on individuals’ posture and locomotion, which should be corrected as earlier as possible. One approach presented just over fifteen years is based on Masai Barefoot Technology (MBT), which claims improvements in gait and posture of the subject.

The key of MBT footwear lays on their sole construction. It provides a comfortable heel strike and creates a natural instability that can help the body generate muscle activity in the lower limbs. The curved sole with its integrated balancing area requires an active and controlled rolling movement that can help the body to improve balance and posture while standing and walking.

The approach used to develop this monograph consisted on the following steps: a) lower limb anatomical and physiological review, more specifically the muscles, bones and joints that are essential to walk; b) gait cycle review, taking into account the events of each of its phases and subphases; c) presentation the state of art of instrumentation available and widely used to quantify biomechanical variables, and also a description and analysis of the most relevant studies conducted with MBT shoes. Finally, we present a brief description of the work plan to be performed in the Master project related to this monograph.


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Index

1 - Introduction .............................................................................................................................. 1

2 - Lower limb and Waist pelvic anatomic constitution ................................................................ 4

2.1 - Introduction ....................................................................................................................... 4

2.2 - Lower limb bone constitution ........................................................................................... 4

2.3 - Lower limb joints .............................................................................................................. 6

2.4 - Lower limb muscles .......................................................................................................... 6

3 - Gait cycle ................................................................................................................................. 9

3.1 – Introduction ...................................................................................................................... 9

3.2 – Gait cycle phases ............................................................................................................ 10

4 - State of the art ........................................................................................................................ 13

4.1 – Introduction .................................................................................................................... 13

4.2 - Methods of gait analyses ................................................................................................. 14

4.2.1 - Visual gait analyses .................................................................................................. 15

4.2.2 - Electromyography .................................................................................................... 16

4.2.3 - Markers associated to video-cameras ....................................................................... 18

4.2.4 - Force platforms ........................................................................................................ 20

4.2.5 - Pressure platforms .................................................................................................... 21

4.3 - Masai Barefoot Technology (MBT) ................................................................................ 22

5 - Conclusions ............................................................................................................................ 29

6 – Work Plan .............................................................................................................................. 30

6.1 – Introduction .................................................................................................................... 30

6.2 – Work plan for the Master project ................................................................................... 30

7 - References .............................................................................................................................. 31


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Figure Index

Figure 1: An example of a MBT shoe (from [7]). ......................................................................... 2

Figure 2: Lower limb bone constitution: waist pelvic and lower limb a), and foot b) (from [5]). 5

Figure 3: Lower limb muscles (from [5]). ..................................................................................... 8

Figure 4: Positions of the legs during a single gait cycle by the right leg (from [5]). ................... 9

Figure 5: Time dimensions of the gait cycle (from [13]). ........................................................... 11

Figure 6: On-off patterns of EMG activity in gait cycle (from [13]). ......................................... 12

Figure 7: Typical instruments in gait laboratory (adapted from [5]). .......................................... 15

Figure 8: Schematic view of SEMG application within a gait analysis laboratory. The basic

instrumentation is represented: TV-based motion analyser for retro-reflective markers detection,

dynamometric force platform for ground reaction measurement, the portable device and the

fixed unit of a radio-telemetric EMG system (from [17]). .......................................................... 17

Figure 9: Schematic representation of a force platform (from [21]). .......................................... 21

Figure 10: Results of force platform measurements: static assay a) and dynamic assay b). ....... 21

Figure 11: EMG data when walking with regular shoes and with the Masai barefoot technique

(MBT). Curves are mean (SD) for walking with regular shoes (—) and with the Masai barefoot

technique (MBT) (- - - -) (from [25]). ......................................................................................... 23

Figure 12: Illustration of the differences in center of pressure movement during quiet standing in

an unstable test shoe and a stable control shoe (from [26]). ........................................................ 24

Figure 13: Schematic representation of pressure distribution characteristics in different shoe

types compared to flat-soled trainers (from [7]). ......................................................................... 25


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Table Index

Table 1: Definition of kinematic and kinetic prime variables used in Buchecker study (adapted

from [22]). ................................................................................................................................... 27


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1 - Introduction Since ever, Human Being has tried to understand complex biomechanical

movements. For example, in classical Greece and Rome, the artists painted and sculpted Man in different positions and alignment of the limbs during varied activities [1]. Actually, many are the names behind the understanding of the biomechanical knowledge as Aristotle, Borelli, Galvani, Newton and Descartes, among others, who developed theories and mechanisms, that without them the biomechanics as we know it would not be possible [1, 2].

The clinical gait analysis can be defined as the measurement, processing and systematic interpretation of biomechanical parameters that characterize human locomotion and ability to identify limitations in motion in order to identify appropriate procedures for rehabilitation [3].

The clinical application of gait analysis allows the physician to quantitatively assess the degree to which an individual's gait was affected by a disease already diagnosed. This process involves the measurement of fundamental biodynamic parameters, the compilation of these data into an information set, systematic interpretation of the information collected with regard to the identification of deviations from the standards values considered as 'normal'. Finally, the objective is the understanding the cause of these abnormalities, as well as the recommendation of treatment alternatives for individual patients on a case by case basis. Thus, clinical gait analysis is currently an evaluation tool and not a diagnostic tool [3, 4].

Currently, clinical gait analysis is a fundamental step in medical treatment of many diseases and disorders. Besides the evaluation of gait in orthopedics (for example, in amputees who use prostheses), are also clinical evaluations of other diseases such as polio, cerebral palsy, multiple sclerosis, rheumatoid arthritis and muscular dystrophy. This analysis is of great importance and actively assists the choice of appropriate treatment of patients with the diseases listed.

In gait analysis, we can divide the data in two groups: kinetics and kinematics data. These terms are commonly used in gait analysis and therefore deserve some explanation. Kinetics is the study of forces, moments, masses and accelerations, but without any detailed knowledge of the position or orientation of the objects involved. Kinematics describes motion, but without reference to the forces involved. For example, a force platform, an instrument used in gait analysis, can be used to measure the force beneath the foot during walking (kinetics), but it gives no information on the position of the limb or the angle of the joints (kinematics). An example of a kinematic instrument is a camera, which can be used to observe the motion of the trunk and the limbs during walking, but gives no information on the forces involved. It is obvious that for an adequate quantitative description of an activity such as walking, both kinetic and kinematic data are needed [5].


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A major objective of the biomechanical analysis is to provide inside information to choose treatments to improvements in movement area. These solutions can undergo surgical procedures or non-invasive methods such as physiotherapy. In the last fifteen years, a new type of footwear appeared on the market that, among other benefits, the company affirms that it has the capacity for recovery and rehabilitation certain movement and posture deviations. That footwear was based on the Masai Barefoot Technology (MBT).

Masai Barefoot Technology was born in 1996 after the discovery of the natural

instability that has remarkable health benefits. It was understood that the human body was not designed for walking or standing on the flat surface of modern society. Hence, a new type of footwear was developed, which would simulate a walk on the beach and a smooth and irregular surface. MBTs are now sold in over 35 countries around the world and its users testify that the MBT significantly increases their welfare [6]. In Figure 1, can be seen a MBT shoe.

Figure 1: An example of a MBT shoe (from [7]).

Therefore, it becomes increasingly necessary to study different cases and variables associated with the use of MBT technology to test its efficacy.

The purpose of this monograph is do a search of the equipment currently used in

most biomechanical analysis of movement and posture, and also identify what studies have been conducted to test the efficacy of MBT shoes, and if this effectiveness is or not proven.

In order to make a proper gait and posture analysis , with a choice of solid and appropriate variables is necessary to know correctly the steps involved in gait, and the anatomical constitution of the members involved in that process. Thus, in chapters 2 and 3, will be presented an anatomical description of the lower limbs, as well as the processes taking place in the gait cycle, respectively.


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After that, in chapter 4, the state of art of techniques used in gait analysis will be present, as well as studies regarding MBT shoes, in order to check the differences developed in gait when those shoes are used in relation to the “normal” gait.

In chapter 5, we will focus the main conclusions to be drawn from this study. Finally, after performing the state of art, and knowing what has been accomplished in

the area, the work plan to accomplish during this Master project will be present (Chapter 6).


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2 - Lower limb and Waist pelvic anatomic constitution

2.1 - Introduction

In order to understand the Human gait is necessary to know the constitution of the limbs that have a key role on the human locomotion: waist pelvic and lower limb. From anatomy and physiology point of view, the main components required for the understanding of the movement are bones, muscles and joints between them.

We move because the muscles push the bones, but the movement required cannot be possible if we did not have joints between the bones. A joint is a place where two bones join, and without them we would “like statues”, when the movement of one bone over another would not be possible. The joints are usually considered motion, but not in all cases. Many joints allow only limited movements and other do not have movement. The structure of the joint relates directly to their degree of movement [8].

Bones and joints are two of the three anatomical and physiological determinant factors for gait execution, the third being the muscles. Muscle cells work like small engines to produce the forces responsible for limb movement, and more generally of the body.

We use our muscles constantly even when we are not moving. The postural muscles repetitively contract to keep us seated or standing. Every kind of communication involves the skeletal muscles, either to write or speak. Even non-verbal communication (gestures or facial expressions) requires the functioning of skeletal muscles. The mobility of the human being, as all the other activities we know, would be impossible without the existence of the muscles [8].

This section is organized to explore the constitution of the lower limb; since, these

anatomical elements have a role in human gait and, consequently, their knowledge is essential for a correct understanding and implementation of biomechanics studies of movement.

2.2 - Lower limb bone constitution

All bones in the human body participated in the gait process. However, from a practical standpoint, for this purpose, we consider only the bones of the pelvis and leg. These bones (Figure 2) support the body and are essential to stand, walk and run normally [5, 8].

The pelvis is formed by the sacrum, coccyx and two innominate bones. The sacrum is the fusion of five sacral vertebrae. The coccyx is a vestigial bone, consisting of three, four or five rudimentary vertebrae. The innominate bone on each side is formed by the fusion of three bones: the ilium, ischium and pubis. The three bones join near the center


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of the acetabulum. The articular surface of the ilium joins the sacrum to form the sacroiliac joint. On each side of the lower part of the pelvis is the acetabulum, which is the proximal part of the hip joint, being the socket into which the head of the femur fits [5, 8].

The only real movement between the bones of the pelvis occurs in the sacroiliac joint and this movement is generally very small in adults. For the purpose of gait analysis, it is reasonable consider the pelvis as a single rigid structure [5].

The thigh contains a single bone, the femur. The femur is the longest bone of the body. It has a spherical head that articulates with the acetabulum of the pelvis forming the hip joint. The bone widens at its lower end to form the medial and lateral condyles. The condyles form the proximal part of the knee joint [5, 8].

The patella is a sesamoid bone, i.e. it is embedded within a tendon, in this case the femoral quadriceps tendon, which below the patella is known as the patellar tendon [5].

The leg is the part of the lower limb situated between the knee and ankle and is composed of two bones: the tibia and fibula. The tibia is by far the larger of two bones and supports most of the weight of the leg. The fibula does not articulate with the femur but has a small head which articulates with the proximal tibia. The tibia and fibula are in contact with each other in superior and inferior part [5, 8].

The proximal portion of the foot consists of seven tarsal bones. The astralagus (or talus) articulates with the tibia and fibula forming the ankle joint (ankle joint). The calcaneus, is located below the astralagus and supports it. The proximal portion of the foot is much larger than the fist. Finally, we have the metatarsal bones and phalanges [8].

Figure 2: Lower limb bone constitution: waist pelvic and lower limb a), and foot b) (from [5]).

a) b)


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2.3 - Lower limb joints

A joint occurs when a bone is in contact with another bone. Joints are structurally classified as fibrous, cartilaginous and synovial. Of these, only the synovial present motion. As the gait analysis is usually focused on reasonable movement, only the synovial joints will be described [5, 8].

The hip joint is usually considered as the only truly spherical joint in the whole body, where the ball is the head of the femur and the acetabulum socket of the pelvis. The femoral head is more like a full sphere than any other bone of the articular surface of the body. The hip is capable of a wide range of motions, including flexion, extension, abduction, adduction, rotation and circumduction [5, 8].

The knee joint is traditionally classified as a modified trochlear joint, located between the femur and tibia. This is a bi-condyle complex joint that allows flexion, extension, and a small rotation of the leg. This linkage has the peculiarity of being surrounded by large synovial pockets [8].

The ankle joint has three surfaces: superior, medial and lateral. The superior surface is the principal surface: is cylindrical and is formed by the tibia above and below the astragalus. The medial part is between astragalus and upper medial malleolus of the tibia. Correspondingly, the lateral surface of the joint is between the upper surface astragalus and of the lateral malleolus of the fibula.

Beyond that joints, there are joints between the bones of the feet as the subtalar or talocalcaneal, the mediatarsal, the tarsal metatarsal, the metatarsal-phalangeal and interphalangeal, which are numerous and complex, and will not be described in this monograph [5].

2.4 - Lower limb muscles

The muscles of the lower limb can be divided into the muscles involved in movement of the thigh, the leg muscles and the muscles of the ankle and foot. Several thigh muscles have their origin in the hip and fit into the femur. These muscles can be divided into three groups: anterior, posterolateral and deep, Figure 3.

The anterior muscles (iliacus and psoas major) flexing the thigh. As these muscles

share a common insertion and produce the same movement, they are often called iliopsoas. Posterolateral muscles that move the thigh are the gluteus medius and tensor fascia lata. The gluteus maximus is the muscle that contributes with the largest part of


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muscle mass. The hip deep muscles function that as external rotators of the thigh. The medium and small gluteus help tilt the pelvis in gait.

Anterior thigh muscles are the quadriceps crural (or femoris) and sartorius. More specifically, the quadriceps femoris is consisted of four muscles: Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius. The quadriceps muscles make the knee extension. The rectus femoris also flexes the hip before it crosses the hip and knee. The sartorius is the longest muscle in the human body, across the outside of the hip to the inner knee. When contracts, the sartorius causes hip flexion and external rotation of the leg and thigh. The group of internal thigh muscles is mainly involved in adduction of the thigh. Some of these muscles are also external rotation of the thigh and/or hip flexion and extension. Additionally, the rectum makes the internal knee flexion. The hamstrings are composed by biceps femoris, the semimembranosus and the semitendinosus. Its tendons are easily seen and palpated in the inner and outer portions of one knee slightly bent [8].

The leg muscles that move the ankle and foot can be divided into three groups, each located in separate compartments in the leg: anterior, posterior and external. The anterior muscles of the leg are extensor muscles that are involved in flexion and foot inversion and extension of their fingers. The superficial muscles of posterior compartment, gastrocnemius and soleus form the "belly" of the leg. These muscles join with the plantar muscle to form a common tendon, the Achilles tendon, and are involved in the foot extension. The deep muscles of the posterior compartment make the extension and inversion of foot and fingers flexion. The external muscles are primarily foot eversion, but also help in the extension. The intrinsic muscles of the foot make the foot flexion, extension, abduction and adduction of the fingers [8].

http://en.wikipedia.org/wiki/Rectus_femoris

http://en.wikipedia.org/wiki/Vastus_lateralis

http://en.wikipedia.org/wiki/Vastus_lateralis

http://en.wikipedia.org/wiki/Vastus_medialis

http://en.wikipedia.org/wiki/Vastus_intermedius

Gait and posture evaluation in r

Figure

In summary, our anatomical and

movement. The bones give us structure, the joints between them provide the ability to move and the muscles work to push the body to move.

The principal joints of the lower limb are hip, knee and ankle joint, tmajor bones in motion: pelvis, femur, fibula, tibia and foot bones.gluteus, gastrocnemius, vastus and peroneus are the components that exert the force necessary to allow movement.

Variations in one or more of those essential their knowledge.


Figure 3: Lower limb muscles (from [5]).

In summary, our anatomical and physiological constitution is drafted to allow movement. The bones give us structure, the joints between them provide the ability to move and the muscles work to push the body to move.

The principal joints of the lower limb are hip, knee and ankle joint, tmajor bones in motion: pelvis, femur, fibula, tibia and foot bones. The muscles like gluteus, gastrocnemius, vastus and peroneus are the components that exert the force necessary to allow movement.

Variations in one or more of those elements outcome gait alterations

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drafted to allow movement. The bones give us structure, the joints between them provide the ability to

The principal joints of the lower limb are hip, knee and ankle joint, that linking the The muscles like

gluteus, gastrocnemius, vastus and peroneus are the components that exert the force

outcome gait alterations, making


3 - Gait cycle

3.1 – Introduction

Human gait is a very complicatedA gait cycle is defined as

until the next heel contact stance phase and swing phasesecond, where 60% is due to theFigures 4 and 5. While anycycle, the initial contact of a foot with

Figure 4: Positions of the legs during a single gait cycle by the right leg

This section is organized to

and which are the characteristic movements knowledge of the constitution of the lower limb, this knowledge is also extremely important for proper understand


Human gait is a very complicated coordinated series of movements. as the period from heel contact of one foot of the same foot with the floor, and can be divided

swing phase, Figure 4. In average, a gait cycle has the duration ofdue to the stance phase and 40% of swing phase, as we can see in

any event can be chosen to define the beginningof a foot with the ground is usually used for that

Positions of the legs during a single gait cycle by the right leg (from

is organized to explain the gait cycle, especially the way it is divided, and which are the characteristic movements and events of each phase and subphase. As knowledge of the constitution of the lower limb, this knowledge is also extremely important for proper understanding and development of biomechanical studies.

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with the ground an be divided into the

the duration of 1 , as we can see in

to define the beginning of the gait for that purpose [5, 9].

(from [5]).

gait cycle, especially the way it is divided, of each phase and subphase. As

knowledge of the constitution of the lower limb, this knowledge is also extremely ing and development of biomechanical studies.


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3.2 – Gait cycle phases

Walking is divided into two main phases: 1) The stance phase is the weight bearing portion of each gait cycle. It is initiated by heel strike and ends with toe off of the same foot. 2) Swing phase is initiated with toe off and ends with heel strike.

The stance phase is subdivided into: 1. Initial Contact - is the time when the posterior foot touches the ground.

Typically, the heel is the first part of the foot touching the ground. The posterior leg part is at the end of terminal support subphase.

2. Loading response - begins when the whole foot is on the ground and involves the short period that is double supported by the lower limbs. Ends when the opposite foot rises, shifting the weight of the body to the anterior leg (simple support). At this stage, the leg supports the weight of the body in the sagittal and frontal planes, while keeping the movement in progress. The rear leg is in pre-swing sub-phase.

3. Mid-stance - corresponds to the first half of single support. It begins with the elevation of the rear leg (which is in mid swing) and ends when the weight of the body is aligned with the front foot.

4. Terminal stance - begins when the heel of the foot (now in a posterior position) rises and continues until the heel of the front foot touches the ground.

5. Pre-swing - the sub-phase begins with initial contact to the front foot and ends when the other foot rises, initiating the swing phase. There is again a short period in which both legs are supported [5, 10-12].

In the swing phase can distinguish the subphases: 1. Initial swing - begins when the hind foot leaves the ground to move and ends

when the other foot is on the end of a medium support, at which time the body is again aligned with the forefoot.

2. Mid-swing - the period in which the foot, on balance, advances until the corresponding leg localize anterior to the body and the tibia is vertical.

3. Terminal swing - the anterior leg continues to move forward, in order to get into a position anterior to the thigh. The sub-phase ends when the front foot touches the ground, beginning a new cycle [5, 10-12].

In each gait cycle, there are two periods of double support and two periods of single

support (see Figure 5).


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Figure 5: Time dimensions of the gait cycle (from [13]).

In “normal” gait, there are movements in different segments of the body that deserve

a special attention and are described in the following. In the movements of the foot, can be distinguished plantar flexion, which occurs

from the back heel at initial contact, to mid-stance, and dorsiflexion, that is because the tibia is put forward, which remains until the foot is set in the swing phase. There are still times when the foot is neutral, especially when it is totally supported on the floor.

There is flexion of the leg during all the stance phase and since from initial swing to mid-swing. Its extension takes place in the remaining periods of the cycle. The thigh is flexed whenever there is advancement of the lower limb in question and in extension when performing the opposite movement.

All the movements described above occurring in the sagittal plane (anteroposterior axis); however, there are also important movements in other planes, such as in the transverse plane, like pelvic rotation (on the vertical axis), that occurs earlier in the leg during the swing and then in the mid-stance. Pelvic rotation is maximal when the heel touches the ground [10-12].

For a better understanding of which muscles and joints were involved in each phase of the gait cycle, a diagram of the muscles and joints that are active during the sub-phases of stance phase is presented in Figure 6.


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Figure 6: On-off patterns of EMG activity in gait cycle (from [13]).

In general, one can say that the gait cycle has two phases (stance and swing), each one divided into subphases. The division into subphases takes place through key moments of the foot’s movement. In each subphase, the movement is performed by different muscles which required different efforts in the joints. The combined knowledge of the gait cycle phases and the anatomical components involved in the movement are important and give a better understanding on the human locomotion.


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4 - State of the art


Over the years, the biomechanical analysis of the Human movement has always interested the Human Being. The first recorded on human locomotion is attributed to Aristotle (384–322 BCE). However, it was from the nineteenth century that this area began to be intensively studied, by names like brothers Willhelm or Eduard Weber, who made great contributions based on very simple measurements [14].

Measurement technology has also experienced a major breakthrough in this century through Jules Etienne Marey, Eadweard Muybridge. Finally, the pioneers in clinical gait analysis are David Sutherland, Jacquelin Perry and Jurg Baumann [14].

The choice of equipment in a clinical gait assessment is a predominant step. The choice of material has to enable the achievement of the variables that need to be assessed, with maximum quality and precision. Hence, it is necessary to know the equipment currently available, to make a correct and conscious choice.

Currently, many biomechanics movement analysis of the human movement are realized as a way to find the best solution for the treatment of some diseases, which may cause biomechanical problems. Recently, a new technology in footwear (Masai Barefoot Technology) appeared on the market and among the advantages conferred upon it, has the peculiarity that helps to prevent injuries and may play a key role in recovery and rehabilitation processes.

According to the MBT Company, “an MBT shoe is a physiological footwear: it makes much more than conventional shoes. Is specifically designed to strength and tone your body, help prevent injuries and recovery or rehabilitate the body. Over 10 years of research were used to achieve the MBT as we know them today, capable of maintaining a good posture when walking or standing to remain and improve their quality of life” [6].

Thus, it becomes important to know the previous studies realized in this area and if there are really differences in gait and posture of the individuals who use these shoes, when compared to normal shoes.

This section presents the state of the art of the equipment used in biomechanical analysis and a description of the main and most relevant studies realized with MBT shoes.

Thus, in section 4.2, a description of major equipment and techniques used in gait analysis, which were chosen based on studies in the area, will be presented.

Then, in section 4.3, studies with MBT shoes, emphasizing their objectives, the way the studies were developed, the variables analyzed and the techniques chosen and the results obtained, will be presented and described.


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4.2 - Methods of gait analyses

In 1988, Roy B. Davis wrote “there are two groups of people who are particularly interested in the dynamic of human motion. The first group includes athletes, and coaches and trainers of athletes who seek to optimize performance and avoid injury through the detailed examination of human movement. The second group includes clinicians who work to identify the underlying etiology of movement abnormalities so that appropriate corrective measurements may be taken” [15]. More than 20 years later that affirmation continues to be true, and make sense.

In the same article, Davis presents technologies and techniques that were used in the assessment of human locomotion in 1988. Linear measurements, plots of the orientation of limb segments, presentation of the ground force reactions, record of electromyography and a videotape of the gait were the information possible to obtain through the technologies existing at the time, including force platforms, pressure platforms, EMG data collection and Video Systems. Basically, these are the techniques used actually, but now these techniques have suffered improvements compared with those used 20 years ago. Moreover, now the improvement in these techniques allows the evaluation of parameters that at the time was impossible (for example, joint moments) [15].

The same author published, in 1997, another paper where the state of clinical gait analysis at the date was present. At the date, the most usual technique used in gait analysis was optical-electronic based systems that measure the displacement of markers, when this location is essential for a reliable and accurate analysis. He refers that other systems were employed in clinical gait analysis such as force platforms, dynamic electromyography (also referred in the previous article of the same author) and the assessment of metabolic energy during walking as a technique that should be implemented because this technique allows a direct evaluation of one of the primary determinants of gait. The author concludes that “gait analysis technology has continued to improve over the past two decades, with faster systems that deliver more and higher quality data. Measurement protocols for pathological gait assessment have been significantly refined over the past decade so that data can be collected reliably and practically” [4].

Another interesting perspective is presented by Richard Baker [16] that in addition to the method of markers interacting with video cameras also refers some criteria that the data must comply, namely reproducible, stable, accurate, appropriately validated, capable of distinguishing between normal and abnormal, must not alter the function it is measuring, reported in form analogous to accepted clinical concepts. Additionally, Frigo [17] refers some of these criteria in his study about surface EMG in clinical gait analysis. Hence, it is necessary that the equipment allows obtaining data with these characteristics.


Through the informationare: markers associated withelectromyography. BeyondFigure 7. Hence, these devices

Figure 7: Typical instruments in gait laboratory

4.2.1 - Visual gait analyses

Visual gait analysis is the oldest method used for this purpose.is, in reality, the most complicated and versatile form of analysis available, because it suffers from serious limitations:events, it is only possible to observe movementscompletely on the skill of the individual subjective and the quality of the analyit. This analysis can be made directly or through video recording

The general gait parameters obtained by this method are:• Cycle time or Cadence;• Stride length; • Speed.

Pressure platforms


information gathered appears that the most devices usedassociated with video systems, force platforms, pressure platforms

Beyond these, visual gait analyses are also constantly adopteddevices, will be described in more detail.

Typical instruments in gait laboratory (adapted from [5]).

Visual gait analyses

Visual gait analysis is the oldest method used for this purpose. However, this method is, in reality, the most complicated and versatile form of analysis available, because it suffers from serious limitations: it is transitory, the eye cannot observe high

t is only possible to observe movements and most important ion the skill of the individual observer. Visual gait analysis is entirely

subjective and the quality of the analysis depends on the skill of the person performing This analysis can be made directly or through video recording [5].

The general gait parameters obtained by this method are: Cadence;

Pressure platforms

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used in gait analysis , pressure platforms and

constantly adopted,

).

However, this method is, in reality, the most complicated and versatile form of analysis available, because it

he eye cannot observe high-speed and most important it depends Visual gait analysis is entirely

sis depends on the skill of the person performing


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Cadence is the number of steps per minute, and it is obtained counting the number of individual steps taken during a minute. Cycle time is the period required to complete one cycle of gait. Stride length can be determined in two ways: by direct measurement or indirectly from the speed and cycle time. The simplest direct method of measurement is to count the strides taken while the subject covers a known distance. The speed may be measured by timing the subject while he/she walks a known distance [5].

4.2.2 - Electromyography

Electromyography (EMG) is defined as the measurement of the electrical activity of a contracting muscle. As EMG measures electrical activity (and not mechanical), the EMG cannot be used to distinguish between concentric, isometric and eccentric contractions, considering all the contractions of the same type, so the relationship between EMG activity and the force of contraction is far from straightforward.

There are three methods of recording the EMG: by means of surface, fine wire and needle electrodes. In gait analysis, EMG is usually measured with the subject walking [5]. Taking into account all aspects related to the types of available electrodes, the electrode surface is, by far, the most used [17].

The main problem with the use of EMG is that it is at best only a semi-quantitative technique, so it gives minor indication of the strength of contraction of individual muscles. The other problem with EMG is that it is difficult to obtain satisfactory recordings from a walking subject. This depends of the electronic characteristics of the equipment being used and to the skills of the operator in selecting the recording sites and in attaching the electrodes, to minimize skin resistance and movement artifacts. The EMG signal is generally processed to provide a visible indication of muscle activity [5].

Carlo Frigo [17] affirms that most myoelectric signals are collected by 8-12 sets of electrodes in a bipolar configuration and connected a preamplifier positioned a few centimeters from the contact points, Figure 8. The connections between the portable equipment and receiving unit (connected to a computer and appropriate software) are realized by cables, optical fibers or radio-telemetry. For all these cases, specific procedures of signal conditioning must be performed before transmission, like data sampling, analog-to-digital conversion, multiplexing, and coding. After that, the analyses of the signal were performed by appropriate software.

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Figure 8: Schematic view of SEMG application within a gaitinstrumentation is represented: TVdetection, dynamometric force platform for ground reaction measurement, the portable

device and the fixed

The choice of the electrodes must be done taking into account the muscles we want to study. There are some criteriachoice of electrodes for gait analysis. Theelectrodes is the most critical issue, and no other means than fineavailable to collect electrical activity from functionally relevant deep muscles such as ilio-psoas and tibialis posterior. electrode surface, which can be small muscles they become less adequate, due to the low selectivity and the possible interference by signals from a

To obtain the data is necessary to takepreparation, the place of theaccount that each electrodepreparation like shaving and useabrasion to reduce keratinized skin layer, and a fundamental. Frigo [17] refers that based on reasonable considerations, between the motor end-point electrodes will see, in all likelihood, all the signals from different muscle fibres propagated in the same direction, and mutual deletwill be minimised. During


Schematic view of SEMG application within a gait analysis laboratory. The basicinstrumentation is represented: TV-based motion analyser for retro-reflective markersdetection, dynamometric force platform for ground reaction measurement, the portable

fixed unit of a radio-telemetric EMG system (from [17

The choice of the electrodes must be done taking into account the muscles we want some criteria that should be taken into account when

gait analysis. The accessibility of the target muscle by surface electrodes is the most critical issue, and no other means than fine-wire probes are available to collect electrical activity from functionally relevant deep muscles such as

psoas and tibialis posterior. Another important point is the relative large volumescan be advantage to obtain data from large muscles

they become less adequate, due to the low selectivity and the possible interference by signals from adjacent or deep muscles [17].

necessary to take into account various factorsthe electrodes, the orientation of electrodes

electrode picks up only the activity of a single muscle. and use alcohol to remove the sebaceous film and light

duce keratinized skin layer, and a proper electrode location is refers that was proposed a new method for electrodes place,

based on reasonable considerations, where the electrodes should be located midway point and the muscle–tendon junction. By this choice, the

electrodes will see, in all likelihood, all the signals from different muscle fibres propagated in the same direction, and mutual deletion of motor units’ action potentials

uring movements, the volume of the contractile tissue will move

17

analysis laboratory. The basic ective markers

detection, dynamometric force platform for ground reaction measurement, the portable 17]).

The choice of the electrodes must be done taking into account the muscles we want when we proceed to

accessibility of the target muscle by surface wire probes are

available to collect electrical activity from functionally relevant deep muscles such as relative large volumes of

muscles, but for they become less adequate, due to the low selectivity and the possible

factors such as skin electrodes, and take into

muscle. Adequate skin alcohol to remove the sebaceous film and light

proper electrode location is a new method for electrodes place,

the electrodes should be located midway . By this choice, the

electrodes will see, in all likelihood, all the signals from different muscle fibres ion of motor units’ action potentials

the volume of the contractile tissue will move


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beneath the electrode surface, and care has to be paid to avoid that the extreme, tendineous part of the muscle might reach the recording zone. As to the orientation of the electrodes, it could be advisable to align them to the direction of muscle fibres, although this parameter can be only roughly estimated on the basis of global muscle anatomy, and, of course, cannot take into account the three-dimensional organization of muscle architecture. It is important to take these factors into account, because its proper use leads the reduction of the artifacts, and consequently the obtainment of more reliable results. Simultaneously, with SEMG acquisition, kinematic and dynamic data are usually collected through TV-cameras, force platforms and pressure platforms, so it is important take into account and minimize the artifacts of the use of all equipment simultaneously [4, 16, 17].

There is no standard format for the EMG information, but normally unchanged and

averaged signal, maximum amplitude while walking, amplitude during maximum voluntary contraction or maximum voluntary exertion were the ways which EMG signals were presented. All of this information should be crossed with temporal parameters such as walking speed, cadence, step length and distance between two successive steps [4].

4.2.3 - Markers associated to video-cameras

The markers and video-camera systems are used to obtain Kinematic data. Kinematic systems are used in gait analysis to record the position and orientation of the body segments, the angles of the joints and the corresponding linear and angular velocities and accelerations [5].

Baker [16] relate retro-reflective markers associated to video-cameras was one of the most important techniques in gait analyses, whilst the basic principles remain the same as the earliest systems, in recent years have seen major advances, especially in speed, accuracy and reliability. The number of cameras but also their quality was a key for the improvements achieved.

Video systems utilize more than one video cameras to track bright markers placed at various locations on the subject. The markers are either infrared (IR) light-emitting diodes (LEDs) for active marker systems or solid shapes covered with retro reflective tape for passive marker systems. The systems keep track of the horizontal and vertical coordinates of each marker from each camera. In 3D systems, the computer software computes 3D coordinates for each marker based upon the 2D data from 2 or more cameras and the known location of all cameras. In general, more than two cameras are needed, as markers become obscured from camera views because some movements that


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take place in the gait [13]. To obtain 3D motions, each body segment must be defined by at least 3 markers, joint centers must be defined, and Euler angles computed.

Active marker systems have LED markers that are pulsed sequentially, so the system automatically knows the identification of each marker. One advantage of this method is that merging of markers cannot occur with these systems, so the markers can be placed close together. These systems have the disadvantage of requiring more equipment on their use.

Passive marker systems have the advantage of using light reflective markers without the need of electrical cables or batteries on the user. IR LEDs around each camera send out pulses of IR radiation that are reflected back into the lens (of camera) from the markers. IR filters are used on the camera lenses and systems thresholds are set to pick up the bright markers while less bright objects in the background are suppressed. An increase in the number of cameras, plus 3-D identification and tracking of markers, now enable laboratory personnel to examine the data for reliability and potential errors while the subject is still present in the laboratory. Because their passive nature, each marker trajectory must be identified with a marker label and tracked throughout the test [13, 18]. The use of markers together with the video system allows to obtain the absolute rotational position of a segment in space or the relative rotational position of two juxtaposed segments. These data can also be combined with the ground reaction values, estimates of segment mass and mass moments of inertia, and the segment/joint velocities and accelerations to compute the net joint moments about particular joint centers, as well as the associated instantaneous joint rotational power.

However, there are still some problems to be worked out. For example, accurate

timing of toe-off is problematic with kinematic methods. The incorporation of force platform input establishes the events of foot-strike and toe-off accurately for those patients able to contact two or more force platforms. Nevertheless, it is the slow walkers, using crutches or a walker, who often exhibit variable or even inaccurate foot-contact times, as calculated from the trajectory velocities of markers on the foot. Another problem is that of marker movement due to skin movements over the underlying skeleton [18].

One area where has been a great development in recent years was the computational technologies used to derive joint kinematics and kinetics from the marker position data supplied by the measurement hardware. Actually, commercial hardware and software available have nearly eliminated problems with marker identification and tracking, thus removing the chief objection to passive marker systems. Today’s a subject can be fitted with appropriate reflective markers and walk down a calibrated walkway, while the markers are automatically tracked, and computations are performed. The resultant joint angles can be viewed within minutes from the end of collection of the data [16, 18].


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According to Baker [16], there is a method that is commonly used to obtain data across markers and video system. This was developed using the minimum number of markers possible to determine 3-dimensional kinematics and kinetics of the lower limb at a time when measurement systems were only capable of detecting a handful of markers. It assumes three degree of freedom joints for the hip and knee and a two degree of freedom joint at the ankle. He said that “The model is hierarchical requiring the proximal segments to have been detected in order that distal segments can be defined and incorporates regression equations to determine the position of the hip joint centre with respect to pelvic markers. Kinetics is determined using an inverse dynamics approach that generally requires considerable filtering to give any useful signals”. This author also calls attention to the correlations and models used to obtain data, which have recently emerged new theories and still do not know well what the right one.

4.2.4 - Force platforms

The force platforms have become a standard kinetic measurement tool that consists of two rigid surfaces, one above and one below, which are connected by force sensors. Typically, the platform is placed on the floor so that its surface is flush with the floor so you can walk normally on it. Force platforms are customarily built as a rectangular device supported at four corners. In each corner, a three-component force sensor is mounted. The sensor is able to register the force in X, Y and Z (or vertical, lateral and fore-aft) directions. The components of the force can be found by algebraic summations of the forces values registered by the individual sensors [19].

Force platforms are generally used to measure, in three dimensions, the magnitude, position and direction of the ground reaction force applied to the feet during the gait and posture studies. The electrical output signals may be processed to produce three components of force (vertical, lateral and fore-aft), the two coordinates of the center of pressure and the moments about the vertical axis. The center of pressure is the point on the ground through which a single resultant force appears to act, although, in reality, the total force is made up of innumerable small force vectors, spread out across a finite area on the surface of the platform. Commonly, this information is used as input, along with kinematic data, to the ‘inverse dynamics’ approach for joint moment estimation using rigid body mechanics [5, 20]. Many specialized types of force platform have been developed over the years, but most clinical laboratories use a commercial platform, a ‘typical’ design being about 100 mm high, with a flat rectangular upper surface measuring 400 mm by 600 mm [5].


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Figure 9: Schematic representation of a force platform (from [21]).

There are two types of force platforms that are widely used: one based on piezo-electric transducers and other based on strain-gauge transducers. From a gait analysis point of view they are similar, no offer some advantage over the other [22].

4.2.5 - Pressure platforms

A pressure platform consists of a set of force transducers with a small surface area over which the mean pressure for that area of contact is calculated (pressure=force/area). For a small number of selected areas of the contact surface, pressures can be measured using individual sensors. The problem with this approach includes choosing the appropriate locations and movement of the sensors during the activity being studied [23]

It is possible to perform static and dynamic tests with this equipment, as can be seen in Figure 10.

Figure 10: Results of force platform measurements: static assay a) and dynamic assay b).

a) b)


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4.3 - Masai Barefoot Technology (MBT)

Several companies have developed ‘‘barefoot’’ shoes with the purpose of providing some of the suggested benefits of barefoot locomotion. Being conceptually similar to wobble board training during injury rehabilitation, the unstable MBT shoe is one of these ‘‘barefoot’’ shoes designed to train or activate some of the extrinsic muscles while standing or walking [24].

Since the appearance of unstable shoes, which advantages both in terms of posture and walking, especially at the joints. However, there are still many studies in this area, which leads to requiring more research in this area.

In this subsection will be present the relevant studies conducted in the area.

Jacqueline Romkes et al. [25] developed a study-design compared walking with regular shoes and Masai barefoot technology. Initially, twelve healthy subjects underwent 3D gait analysis with simultaneously collecting surface electromyography (EMG) data of the leg muscles when walking with regular shoes and with Masai barefoot technology shoes. Then the subjects were trained with MBT for a period of at least 4 weeks to ensure the appropriate MBT-technique. All subjects were able to wear the shoes for a full day at the time of testing. 3D gait data were collected through a system of cameras, were used 15 markers (of 25 mm diameter) placed on the right and left anterior superior iliac spines, lateral midthigh, lateral midshank, lateral femoral epicondyle, lateral malleolus, second metatarsal head, calcaneus, and one marker on the sacrum. The heel and toe markers were placed on the shoes at the positions best projecting the anatomical landmarks. Regarding EMG, bipolar Ag/AgCl surface electrode pairs with an electrode diameter of 10 mm and an inter-electrode spacing of 22 mm were placed on the clean shaven skin overlying the medial gastrocnemius, lateral gastrocnemius, tibialis anterior, vastus medialis, vastus lateralis, rectus femoris, and semitendinosus muscles of the subjects preferred leg when hopping.

This study demonstrated that when compared to walk in regular shoes, the time-distance parameters like the cadence, stride length, step length, and walking speed were significantly decreased during the MBT condition. However, stride time, and single support significantly increased during the MBT condition. No significant differences in the kinematic data from the frontal and transverse planes were found. For the sagittal plane movements, pelvic tilt did not alter when walking with MBT, but subjects had a reduced range of motion (RoM) throughout gait at the hip joint. This was due to a reduction in both peak hip flexion and peak hip extension. Similar results were observed for knee joint. At the knee-joint-complex the dorsiflexion angle is superior with MBT.

The electromyography results show that activity of the semitendinosus muscle did not show any alterations when walking with MBT compared to walk with regular shoes. For the other muscles, the level of activity suffered different oscillations, Figure 11, [25].


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Figure 11: EMG data when walking with regular shoes and with the Masai barefoot technique (MBT). Curves are mean (SD) for walking with regular shoes (—) and

with the Masai barefoot technique (MBT) (- - - -) (from [25]).

In 2005, Benno Nigg el al. [26] developed a study, with healthy subjects, to compare

muscle activity, kinematics and kinetics characteristics during standing and walking using a MBT shoe and a stable control shoe. The accommodation period was 2 weeks. Kinematic data were collected simultaneously with Kinetic data through high-speed video camera system and force platform, respectively. Retroreflective markers were placed on the segments of the rearfoot, shank, thigh and pelvis of the right lower extremity. Markers were placed on both sides of the body over the greater trochanters, the medial and lateral femoral condyles and the medial and lateral malleoli. The three


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rearfoot markers were placed directly on the posterior and posterior-lateral aspect of the shoe heel counter. Myoelectric signals were recorded using circular bipolar surface electrodes each one was 10 mm in diameter and had an inter-electrode spacing of 22 mm and was placed midway between the motor end plate and the distal myotendinous junction, on the skin overlying the muscle belly of the tibialis anterior, medial gastrocnemius, biceps femoris, vastus medialis, and gluteus medius of the limb of interest.

The results shows that have relevant differences between the centre of pressure of the subjects with MBT and control shoes (see Figure 12). The mean excursion in medio-lateral direction was 11.91 mm for the MBT and 5.82 mm for the control shoe, and in anterior-posterior direction was 27.25 mm for the MBT and 17.88 mm for the control shoe.

Figure 12: Illustration of the differences in center of pressure movement during quiet standing in an

unstable test shoe and a stable control shoe (from [26]).

In static tests, all muscles showed an increased an EMG intensity from measurements with MBT shoes compared with control shoes. However, for the walking tests no significant differences in EMG activities between the control and the MBT shoe were observed.

The authors do not check relevant differences in kinetics of the three joints for the walking test. From Kinematics, the ankle joint was significantly more dorsiflexed during the first half of stance in the MBT shoe compared to the stable control shoe.

In 2010, the same authors present another study [27] with the objective of verify if exist gender differences (man and woman) during bilateral quiet stance or in lower extremity gait kinematics and kinetics when using unstable shoes.

When wearing unstable shoes gender differences were observed in the anterior-posterior sway during quiet bipedal stance and in the moments controlling the ankle joint movement during the stance phase of the gait cycle. These differences suggest that men and women are affected differently by the instability created by unstable shoes, and that they might use different strategies when compensating for this instability.

L. Stewart et al. [7] developed a study to analyze the distribution of plantar pressures with MBT shoes and flat-soled training shoes. The plantar pressure measurements were


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made with the PEDAR-x system, which consists of pressure sensing insoles connected to a box that attaches around the subjects’ waist and transmits information to the PEDAR-x software via Bluetooth wireless communication. The following variables were analyzed: mean pressure (kPa), average pressure over all the frames and peak pressure (kPa), the maximum pressure that occurred in one sensor over the selected frames. The total contact area and the area of all loaded sensors over the insole, were also recorded.

The results (Figure 13) demonstrate that have significant differences between the plantar pressure patterns found in normal subjects wearing MBT shoes compared when the same subjects were wearing training shoes. The main difference occurs in standing tests, where the MBT shoes increased peak pressure under the toes by 76% and lowered peak pressure in the midfoot and heels by 21% and 11%. Similar results were observed for mean pressure for the toes, with an increase of 83% in the standing phase compared with the control. MBT shoes decreased peak pressures in the forefoot and midfoot when walking, and in the midfoot and hindfoot when standing. For the mean pressure results, the MBT shoe decreased the mean pressure in the midfoot and hindfoot regions when both standing and walking. The most consistent finding, when both standing and walking, was a lesser pressure under the midfoot when the subjects wore their MBT shoes [7].

Figure 13: Schematic representation of pressure distribution characteristics in different

shoe types compared to flat-soled trainers (from [7]).

Maetzler [28] studied whether a sensory-motor training can possibly change the muscular activity during gait and in turn lead to a change of pressure distribution which is favourable for diabetic patients. When did the study, the author already knew that Romke found an increase of previous muscle activity, while the trend found in Nigg reduction, In Maetzler’s study, two groups were measured, one with type 2 diabetes subjects and other with non-diabetic normal subjects. The initial measurements were repeated after 6 weeks. During these times, groups 1 and 2 had to wear an unstable shoe construction (Masai Barefoot Technology, MBT) for at least 4 h per day. Their results show that the training with MBT can change pressure distribution not only in healthy but also in diabetic patients. Areas where high pressure showed a decrease and areas with low pressure showed an increase after the use of MBT.


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In 2008 and 2009, Bochdansky [29] and Boyer [30], respectively, realized studies with unstable shoes in order to observe the differences in running with MBT as compared to traditional running shoes.

Bochdansky [29] investigate the differences during downhill walking and running with normal shoe and MBT shoes. The tests were realized in a treadmill. Pressure distribution was measured with Pedar insoles, and EMG (surface electrodes) registered from tibialis anterior (TA), peronaeus (P), vastus medialis of the gastrocnemius (MG) and from the glutaeus medius (GM). The results show significant differences between normal running shoes and MBT shoes. With the MBT shoes, the beginning of contact in the forefoot and the end of contact in the heel occurred earlier. The contact time was longer in the forefoot and heel. For EMG results, only for the gastrocnemius significant differences had been found. The author concludes that when compared normal running shoes walking and running downhill with an MBT shoes, MBT shoes are less stressful for the peak pressure area with the same activity pattern of the muscles.

The aim of Boyer [30] study was to investigate the mechanism of adaptation to a rockered sole shoe in running. Data was captured as subjects ran in a straight line along an 11 m long runway. The experiment consisted of three running trials first for the rockered test shoe and then for the control shoe at a self-selected speed. The results show that there were no significant differences in the hip and knee joint kinematics during the stance phase of running. However, there was a significant decrease in the external ankle dorsiflexion, plantarflexion and inversion joint moments. No changes in the external joint moments were found at the knee or hip. The total peak positive joint power in stance (sum of hip, knee and ankle) was lower in the MBT shoe than in the control shoe.

These two studies [29, 30] suggest it is possible to accommodate substantial changes in the curvature of the sole by changes in the motion and forces sustained at the ankle and can occur with minimal change to the knee or hip motions or moments.

Recently, Buchecker el al, [31] presented a study that evaluate the effect of Masai Barefoot Technology shoes on lower extremity joint loading in overweight males. Ten males were the subjects of this study. Kinetic data were recorded by a force platform and Kinematic data were collected by a video capture system, with markers placed on the anterior superior iliac spines, posterior superior iliac spines, lateral aspects of the thighs and shanks, knee joint axis, lateral malleoli, second metatarsal heads, and heels. Heel and metatarsal heads markers were placed on the shoes and identified via palpation. The kinetic and Kinematic data evaluated in this study is shown in Table 1. EMG activity was measured with bipolar Ag/AgCI surface electrode pairs (18 mm diameter gel area, 10 mm diameter iron contact area, inter-electrode spacing of 30 mm) placed vastus lateralis (VL), biceps femoris (BF) and gastrocnemius medialis (GM). The EMG signal was analyzed using Fast-Fourier Transformation.


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Table 1: Definition of kinematic and kinetic prime variables used in Buchecker study (adapted from [22]).

Variable Definition Ankle joint

Maximum dorsal extension moment

Maximum dorsal extension moment at the ankle during stance phase

Maximum axial loading rate Maximum slope of the axial force at the ankle during first 10% of stance phase

Knee joint

Midstance flexion angle Maximum knee flexion angle during first half of stance phase

Maximum flexion moment Maximum flexion moment at the knee during first half of stance phase

First peak adduction moment Maximum adduction moment at the knee during first half of stance phase

Second peak adduction moment Maximum adduction moment at the knee during second half of stance phase

Maximum axial loading rate Maximum slope of the axial force at the knee during first 10% of stance phase

Hip joint

Maximum flexion moment Maximum flexion moment at the hip during stance phase

Maximum axial loading rate Maximum slope of the axial force at the hip during first 10% of stance phase

Concerning frontal plane walking kinetics, overweight subjects had lower first peak knee adduction moments and similar second peak knee adduction moments using MBT shoes compared with the standard shoes. The authors analyzed that at the time of the first peak knee adduction moment, the center of pressure shifted more on the lateral side and medial ground reaction forces were decreased when walking with MBT shoes. For all muscles, no statistically differences were found between walking with MBT shoes or control shoes in loading response phase. However, in the midstance phase the intensitie of vastus lateralis and, consequently, co-contraction indice of valgus lateralis and gastrocnemius medialis (V/O) showed increased when walking with MBT shoes. Similarly, in the terminal stance the intensity of vastus lateralis, gastrocnemius medialis and V/O co-activation were increased when walking with MBT shoes.

The studies realized in MBT area, are usually focused on walking and shown that altering the anterior muscles rocker of the shoe produces the greatest adaptations at the ankle joint. These studies reported significant decreases in the ankle dorsi-flexion angles in stance, trends for reduction in the ankle sagittal and frontal plane joint moments and small changes in the knee or hip sagittal plane joint motions and moments. The changes in anterior muscles resulting for the use of MBT shoes have also been shown to be effective in stimulating muscle activity [25, 26].


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However, through the present studies, it appears that there is still no total agreement on what really changed using MBT. For example, in some studies, no significant differences in muscle activity were uncovered [31], which happen to be seen in other studies [25, 29]. Moreover, different muscles were affected in each study [25, 26, 29, 31]. Nigg study [26] relates differences in muscle activity in a static position but not in dynamic studies. The present studies are also inconclusive whether the use of MBT really affects joint moments.

The daily time walking with MBT shoes differ from study to study, but the period of the study was similar (six or eight weeks).

Notwithstanding, we can verify that the techniques and equipment used in these studies were the same described in subsection 4.2, which corroborates that these are the most common techniques used in the area.

In conclusion, although there is a pattern of changes similar in all studies conducted with MBT, it is clear that they are not yet able to recognize a pattern for some biomechanics variables. Hence, it is necessary to conduct further studies to test the changes in the movement produced by MBT.


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5 - Conclusions

Understanding gait and body's biomechanics is difficult at the best of times. However, it is worth trying because it will help explain the cause of some of the little niggles, or even large deviations in gait. This is an area with many aspects still unexplained, due to the complexity and multidimensionality of biomechanical analysis.

Biomechanical studies are not performed with the aim of changing the movement, but to detect changes that occur in movement. The multiplicity of motor responses given by Man through its locomotors system is related to factors that own system, by the way has the ability to manage on their relationship with the outside of energy and changes processed.

As already mentioned, the use of biomechanical analysis of movement as a diagnostic method and choice treatment, becomes increasingly important.

Biomechanical analysis of movement also has an important role to test the efficacy

of new products and treatments that are considered relevant in biomechanical, as is the case with MBT shoes. These shoes, among other things, were defined as a device capable of assisting in the rehabilitation and treatment of human movement.

Thus, it is necessary to carry out studies to test the effectiveness of Masai Barefoot Technology. These studies should be as accurate as possible, and should use a range of equipment to provide reliable information and that can be reviewed in line.


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6 – Work Plan


This monograph has as objective the preparation of the Master project to be undertaken during next semester. Thus, taking into account the research and study of the state of art, presented in previous sections, this section introduces, in general, the foreseen work plan as so the objectives.

6.2 – Work plan for the Master project

In general, it is intended with this Master project in Bioengineering, from a biomechanical point of view, study differences of human movement and posture settled by the use of MBT shoes compared with the use of regular footwear.

The main objectives are to study, through the most appropriate methods and devices, differences in posture and gait found between the use of MBT shoes and normal shoes, through kinetic and kinematic data, like forces and moments applied to joints and the force exerted by the major muscles of the lower limb.

To conduct the studies mentioned, data will be collect for a sample of thirty volunteered subjects that will be dividing in two groups. The trial group will wear unstable shoes during 8 weeks and the control group will use regular shoes during the same period. Before the first data acquisition, all subjects will be subject an instruction session by a qualified instructor who will explain them how to use the unstable test shoes, followed by a period of time walking, until the subjects felt comfortable using the shoes.

Before and after the 8th week, kinetic and kinematic data will be accessed.

Thus, it will seek to establish a relationship between the use of MBT and changes verified in gait. It will do a biomechanical analysis of kinematic and kinetic variables obtained, and detect which ones are major differences between the use of two types of footwear.

The collection of this information will provide a characterization of the gait pattern resulting from the use of MBT.


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7 - References

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2. Sutherland, D.H., The evolution of clinical gait analysis part III - kinetics and energy assessment. Gait & Posture, 2005. 21(4): p. 447-461.

3. Davis, R.B., et al., A gait analysis data collection and reduction technique. Human Movement Science, 1991. 10(5): p. 575-587.

4. Davis, R.B., Reflections on clinical gait analysis. Journal of Electromyography and Kinesiology, 1997. 7(4): p. 251-257.

5. Whittle, M., Gait analysis an introduction. Fourth ed. 2007, Oxford Boston: Butterworth Heinemann.

6. MBT. Masai Barefoot Technology. 2011 [cited 2011 12-01-2011]; Available from: http://pt.mbt.com/.

7. Stewart, L., J.N.A. Gibson, and C.E. Thomson, In-shoe pressure distribution in "unstable" (MBT) shoes and flat-bottomed training shoes: A comparative study. Gait & Posture, 2007. 25(4): p. 648-651.

8. Seeley Rod R., S.T.D., Tate Philip, Anatomia & Fisiologia. Sixth ed. 2006, Loures: Lusodidacta.

9. Griffiths, I.W., Principles of biomechanics & motion analysis, ed. L.W.a. Wilkins. 2006, United States of America.

10. Mickelborough, J., et al., Muscle activity during gait initiation in normal elderly people. Gait & Posture, 2004. 19(1): p. 50-57.

11. Nadeau, S., et al., Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip flexors. Clinical Biomechanics, 1999. 14(2): p. 125-135.

12. Piazza, S.J. and S.L. Delp, The influence of muscles on knee flexion during the swing phase of gait. Journal of Biomechanics, 1996. 29(6): p. 723-733.

13. Delisa, Gait Analysis in the Science of Rehabilitation, Baltimore: Veterans Health Administration

14. Baker, R., The history of gait analysis before the advent of modern computers. Gait & Posture, 2007. 26(3): p. 331-342.

15. Davis, R.B., III, Clinical gait analysis. Engineering in Medicine and Biology Magazine, IEEE, 1988. 7(3): p. 35-40.

16. Baker, R., Gait analysis methods in rehabilitation. Journal of Neuroengineering and Rehabilitation, 2006. 3.

17. Frigo, C. and P. Crenna, Multichannel SEMG in clinical gait analysis: A review and state-of-the-art. Clinical Biomechanics, 2009. 24(3): p. 236-245.

18. Sutherland, D.H., The evolution of clinical gait analysis: Part II Kinematics. Gait & Posture, 2002. 16(2): p. 159-179.

19. Zatsiorsky, V., Kinetics of Human Motion. 2002: Human Motion. 20. Desjardins, P. and M. Gagnon, A force platform for large human displacements.

Medical Engineering & Physics, 2001. 23(2): p. 143-146. 21. Forti, A.M., Utilização da plataforma de força para aquisição de dados cinéticos

durante a marcha humana, Laboratório de Biofísica, Escola de Educação Física e Esporte, Universidade São Paulo: São Paulo.

22. Rezaul Begg, M.P., Computational intelligence for movement sciences: neural networks and other emerging techniques, ed. I.G. Publishing. 2006, London: Idea Group Publishing.

23. Bartlett, R., Introduction to sports biomechanics, ed. R. Bartlet. 1997: E & FN Spon. 24. Landry, S.C., B.M. Nigg, and K.E. Tecante, Standing in an unstable shoe increases

postural sway and muscle activity of selected smaller extrinsic foot muscles. Gait & Posture, 2010. 32(2): p. 215-219.

http://pt.mbt.com/


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