Pronation of the foot
Encyclopedia
Pronation is the inward roll of the foot
while walking
or running
. Another way to look at pronation instead in terms of the degree of inward roll is in terms of where the foot pushes off at the end of each step, or at the end of the gait
cycle.
, is natural in the body’s regular movement. However, overpronation and underpronation, also known as supination, can be potentially harmful. Neutral pronation occurs when the foot experiences a normal, healthy amount of pronation instead of overpronating or underpronating. In healthy movement more of the toe area will be used when pushing off than in unhealthy movement. In neutral pronation the weight distributes fairly evenly among all of the toes with a slight emphasis on the big toe and second toe which are better adapted to handle more of the load.
, leg length discrepancy
, ligamentous laxity
, or because of muscular weakness or tightness in the gastrocnemius
and soleus
muscles." Pronation can be influenced by sources outside of the body as well. Shoes have been shown to significantly influence pronation. Hintermann states that the same person can have different amounts of pronation just by using different running shoes. “It is easily possible that the maximal ankle joint eversion movement is 31 degrees for one and 12 degrees for another running shoe."
There has been some speculation as to whether arch height has an effect on pronation. After conducting a study at the Rose-Hulman Institute of Technology
, Maggie Boozer suggests that people with higher arches tend to pronate to a greater degree. However, the generally accepted view by professionals is that the most pronation is present in those with lower arch heights. To complicate matters, one study done by Hylton Menz at the University of Western Sydney-Macarthur suggests that the methods for measuring arch height and determining whether someone is “flat-footed
” or “high-arched
” are unreliable. He says, “For this reason, studies investigating the relationship between static arch height motion of the rearfoot have consistently found that such a classification system is a poor predictor of dynamic rearfoot function.
”
Hintermann states, “Individuals with injuries typically have pronation movement that is about two to four degrees greater than that of those with no injuries.” He adds however, that between 40% and 50% of runners who overpronate do not have overuse injuries. This suggests that although pronation may have an effect on certain injuries, it is not the only factor influencing their development.
Wearing supportive orthotics
in the shoe is a method commonly implemented to treat many common running injuries that are thought to be associated with pronation. According to R.E. Arendse, a researcher at the Sports Science Institute of South Africa and the University of Cape Town
, “75.5% of injured runners are successfully treated with the prescription of orthoses." In a study conducted by Gross, Davlin, and Evanski at Orthopaedic and Sports Medicine Associate , overpronation and injuries associated with it were the most common reason for diagnosing orthotics. 262 out of the 500 runners involved in the study either had great improvement or complete healing of the injury after wearing the orthotics. The most effective treatment of injuries came in treating symptoms that resulted from unusual biomechanics
within the body such as overpronation. An added advantage of orthotics is that they often allow the runner to continue to participate in athletic activity and avoid other treatment options that could be potentially costly and time consuming.
Roy Cheung, a graduate student, and Gabriel Ng, a professor and Associate Head of Department, both in the Department of Rehabilitation Sciences at the Hong Kong Polytechnic University
, conducted a study showing that foot pronation tends to increase in runners as mileage also increases, potentially increasing the risk for injury. Motion control shoes are a specific type of running shoe designed to limit these excessive foot motions. They have been shown to significantly reduce the amount of plantar
force (a force generated by excess pronation) when compared to normal footwear used in running. Motion control and stability shoes have increased medial support which may increase stability
to the foot and leg and lower the amount of pronation in the foot.
Certain methods of taping
the foot and leg have also been shown to be effective in preventing overpronation. In a study conducted at the University of Queensland
, a taping procedure known as the LowDye taping technique was shown to be effective in controlling pronation during both movement and standing.
Specific patterns of lacing running shoes have also been shown to help reduce pronation. Marco Hagen, a researcher in the Biomechanics Laboratory at the University of Duisburg-Essen
, concludes that, according to his study, when the highest number of eyelets in the shoe is used for lacing and the shoes are tied as tight as possible, pronation is significantly decreased.
Several studies have shown that running barefoot
can decrease pronation on the foot’s impact with the ground. This is thought to be because running shoes have extra weight for cushioning at the heel of the shoe, causing the runner to heel-strike
more, which in turn results in increased pronation during the step. According to Stacoff, Kaelin, and Steussi, researchers at the Biomechanics Laboratory of the Swiss Federal Institute of Technology
, “The least amount of pronation takes place when running barefoot."
Runner’s World states, “[Underpronators] do best in a neutral-cushioned shoe that encourages a more natural foot motion." Since underpronators’ feet don’t roll inward like overpronators’, support isn’t necessarily needed to correct supination as it is to correct overpronation. Instead, extra cushioning in the shoe is the best way to correct underpronation.
The downward dog pose helps stretch the backs of the legs to relieve underpronation.
Foot
The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws...
while walking
Walking
Walking is one of the main gaits of locomotion among legged animals, and is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step...
or running
Running
Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait in which at regular points during the running cycle both feet are off the ground...
. Another way to look at pronation instead in terms of the degree of inward roll is in terms of where the foot pushes off at the end of each step, or at the end of the gait
Gait
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...
cycle.
Types of Pronation
There are three main types of pronation in human gait; neutral pronation, overpronation, and underpronation or supination. While both overpronation and supination occur while walking and standing, they are usually more pronounced and the effects amplified while running.Neutral Pronation
According to B. Hintermann, a doctor in the Orthopaedic Department at Kantonsspital in Basel, Switzerland, some pronation, also called eversionEversion
Eversion is a process of turning inside-out. To Evert means to turn inside out. Eversion may refer to:* Eversion , the anatomical term of motion denoting the movement of the sole of the foot away from the median plane...
, is natural in the body’s regular movement. However, overpronation and underpronation, also known as supination, can be potentially harmful. Neutral pronation occurs when the foot experiences a normal, healthy amount of pronation instead of overpronating or underpronating. In healthy movement more of the toe area will be used when pushing off than in unhealthy movement. In neutral pronation the weight distributes fairly evenly among all of the toes with a slight emphasis on the big toe and second toe which are better adapted to handle more of the load.
Overpronation
Those who overpronate tend to push off almost completely from the big toe and second toe. As a result, the shock from the foot’s impact doesn’t spread evenly throughout the foot and the ankle has trouble stabilizing the rest of the body. Additionally, an unnatural angle forms between the foot and ankle and the foot splays out abnormally. It is common even for people who pronate normally to have some angle between the foot and the ankle, but not to the extent seen in those who overpronate. In normal pronation the weight distributes evenly throughout the foot.Causes of Overpronation
There are many possible causes for overpronation, but researchers have not yet determined one underlying cause. Hintermann states, “Compensatory overpronation may occur for anatomical reasons, such as a tibia vara of 10 degrees or more, forefoot varusVarus deformity
In orthopedics, a varus deformity is a term for the inward angulation of the distal segment of a bone or joint. The opposite of varus is called valgus.The terms varus and valgus always refer to the direction that the distal segment of the joint points....
, leg length discrepancy
Unequal leg length
Unequal leg length or leg length inequality refers to a medical condition where the legs are of different lengths.One form is "leg length alignment asymmetry" which is a condition in physiology where one leg is unequal in length while in a supine or prone position .LLAA can be either anatomical...
, ligamentous laxity
Ligamentous Laxity
Ligamentous laxity is a term given to describe "loose ligaments."In a 'normal' body, ligaments are naturally tight in such a way that the joints are restricted to 'normal' ranges of motion. This creates normal joint stability...
, or because of muscular weakness or tightness in the gastrocnemius
Gastrocnemius muscle
In humans, the gastrocnemius muscle is a very powerful superficial pennate muscle that is in the back part of the lower leg. It runs from its two heads just above the knee to the heel, and is involved in standing, walking, running and jumping. Along with the soleus muscle it forms the calf muscle...
and soleus
Soleus muscle
- References :* Gray, Henry. Pick, T. Pickering, & Howden, Robert . Gray's Anatomy . New York: Barnes & Noble Books.- External links :...
muscles." Pronation can be influenced by sources outside of the body as well. Shoes have been shown to significantly influence pronation. Hintermann states that the same person can have different amounts of pronation just by using different running shoes. “It is easily possible that the maximal ankle joint eversion movement is 31 degrees for one and 12 degrees for another running shoe."
There has been some speculation as to whether arch height has an effect on pronation. After conducting a study at the Rose-Hulman Institute of Technology
Rose-Hulman Institute of Technology
Rose–Hulman Institute of Technology , formerly Rose Polytechnic Institute, is a small private college specializing in teaching engineering, mathematics, and science. RHIT is highly regarded for its undergraduate engineering program, which US News and World Reports ranked in 2011 as No...
, Maggie Boozer suggests that people with higher arches tend to pronate to a greater degree. However, the generally accepted view by professionals is that the most pronation is present in those with lower arch heights. To complicate matters, one study done by Hylton Menz at the University of Western Sydney-Macarthur suggests that the methods for measuring arch height and determining whether someone is “flat-footed
Flat feet
Flat feet is a formal reference to a medical condition in which the arch of the foot collapses, with the entire sole of the foot coming into complete or near-complete contact with the ground...
” or “high-arched
Pes cavus
High arch is a human foot type in which the sole of the foot is distinctly hollow when bearing weight. That is, there is a fixed plantar flexion of the foot...
” are unreliable. He says, “For this reason, studies investigating the relationship between static arch height motion of the rearfoot have consistently found that such a classification system is a poor predictor of dynamic rearfoot function.
”
Effects of Overpronation
Overpronation may have secondary effects on the lower legs, such as increased rotation of the tibia, which may result in lower leg or knee problems. Overpronation is usually associated with many overuse injuries in running including medial tibial stress syndrome, or shin splints, and knee painKnee pain
Knee pain is a common complaint for many people. There are several factors that can cause knee pain. Awareness and knowledge of knee pain causes lead to faster diagnosis and treatment. Knee pain can be related to knee joint or around the knee.-Knee joint:...
Hintermann states, “Individuals with injuries typically have pronation movement that is about two to four degrees greater than that of those with no injuries.” He adds however, that between 40% and 50% of runners who overpronate do not have overuse injuries. This suggests that although pronation may have an effect on certain injuries, it is not the only factor influencing their development.
Orthotics
Wearing supportive orthotics
Arch support
An arch support is a piece of material designed to provide support for the arch of the foot. An arch support may be placed on top of the shoe's insole, or may be part of the insole....
in the shoe is a method commonly implemented to treat many common running injuries that are thought to be associated with pronation. According to R.E. Arendse, a researcher at the Sports Science Institute of South Africa and the University of Cape Town
University of Cape Town
The University of Cape Town is a public research university located in Cape Town in the Western Cape province of South Africa. UCT was founded in 1829 as the South African College, and is the oldest university in South Africa and the second oldest extant university in Africa.-History:The roots of...
, “75.5% of injured runners are successfully treated with the prescription of orthoses." In a study conducted by Gross, Davlin, and Evanski at Orthopaedic and Sports Medicine Associate , overpronation and injuries associated with it were the most common reason for diagnosing orthotics. 262 out of the 500 runners involved in the study either had great improvement or complete healing of the injury after wearing the orthotics. The most effective treatment of injuries came in treating symptoms that resulted from unusual biomechanics
Biomechanics
Biomechanics is the application of mechanical principles to biological systems, such as humans, animals, plants, organs, and cells. Perhaps one of the best definitions was provided by Herbert Hatze in 1974: "Biomechanics is the study of the structure and function of biological systems by means of...
within the body such as overpronation. An added advantage of orthotics is that they often allow the runner to continue to participate in athletic activity and avoid other treatment options that could be potentially costly and time consuming.
Shoe Type
Roy Cheung, a graduate student, and Gabriel Ng, a professor and Associate Head of Department, both in the Department of Rehabilitation Sciences at the Hong Kong Polytechnic University
Hong Kong Polytechnic University
The Hong Kong Polytechnic University specialises in professional education in Hong Kong. The University’s teaching units are grouped under six faculties and two schools; the Faculty of Applied Science and Textiles, Faculty of Business, Faculty of Construction and Environment, Faculty of...
, conducted a study showing that foot pronation tends to increase in runners as mileage also increases, potentially increasing the risk for injury. Motion control shoes are a specific type of running shoe designed to limit these excessive foot motions. They have been shown to significantly reduce the amount of plantar
Plantar arch
The plantar arch is formed from:* deep plantar artery, from the dorsalis pedis - aka dorsal artery of the foot* lateral plantar arteryThe plantar arch supplies the underside, or sole, of the foot....
force (a force generated by excess pronation) when compared to normal footwear used in running. Motion control and stability shoes have increased medial support which may increase stability
Joint stability
Joint stability refers to the resistance offered by various musculoskeletal tissues that surround a skeletal joint. Several subsystems ensure the stability of a joint. These are the passive, active and neural subsystems. The opposite of stability is instability...
to the foot and leg and lower the amount of pronation in the foot.
Taping
Certain methods of taping
Taping
Taping is a form of strapping. It is a procedure that uses tape, attached to the skin, to physically keep in place muscles or bones at a certain position. This reduces pain and aids recovery...
the foot and leg have also been shown to be effective in preventing overpronation. In a study conducted at the University of Queensland
University of Queensland
The University of Queensland, also known as UQ, is a public university located in state of Queensland, Australia. Founded in 1909, it is the oldest and largest university in Queensland and the fifth oldest in the nation...
, a taping procedure known as the LowDye taping technique was shown to be effective in controlling pronation during both movement and standing.
Shoe-lacing patterns
Specific patterns of lacing running shoes have also been shown to help reduce pronation. Marco Hagen, a researcher in the Biomechanics Laboratory at the University of Duisburg-Essen
University of Duisburg-Essen
The University Duisburg-Essen is a public university in Duisburg and Essen, North Rhine-Westphalia, Germany and a member of the new founded University Alliance Metropolis Ruhr....
, concludes that, according to his study, when the highest number of eyelets in the shoe is used for lacing and the shoes are tied as tight as possible, pronation is significantly decreased.
Barefoot Running
Several studies have shown that running barefoot
Barefoot running
Barefoot running is running while barefoot—without wearing any shoes on the feet. Running in thin-soled, flexible shoes, often called minimalist running, such as moccasins is biomechanically related to running barefoot, but alters sensory feedback from the plantar mechanoreceptors...
can decrease pronation on the foot’s impact with the ground. This is thought to be because running shoes have extra weight for cushioning at the heel of the shoe, causing the runner to heel-strike
Gait (human)
Human gait is the way locomotion is achieved using human limbs. Different gaits are characterized by differences in limb movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in the contact with the surface .- Foot strike :One variable in different gaits is...
more, which in turn results in increased pronation during the step. According to Stacoff, Kaelin, and Steussi, researchers at the Biomechanics Laboratory of the Swiss Federal Institute of Technology
ETH Zurich
The Swiss Federal Institute of Technology Zurich or ETH Zürich is an engineering, science, technology, mathematics and management university in the City of Zurich, Switzerland....
, “The least amount of pronation takes place when running barefoot."
Supination (Underpronation)
Supination occurs when the foot impacts the ground and there is not enough of an “inward roll” in the foot’s motion. The weight of the body isn’t transferred at all to the big toe, forcing the outside of the foot and the smaller toes which can't handle the stress as well to take the majority of the weight instead.Shoe type
Runner’s World states, “[Underpronators] do best in a neutral-cushioned shoe that encourages a more natural foot motion." Since underpronators’ feet don’t roll inward like overpronators’, support isn’t necessarily needed to correct supination as it is to correct overpronation. Instead, extra cushioning in the shoe is the best way to correct underpronation.
Yoga
The downward dog pose helps stretch the backs of the legs to relieve underpronation.