question: Why does the bone on our heel not poke through the skin when you run a marathon?
comment: Tl;dr: at bottom Although it may feel soft, there is actually a thick layer of fatty tissue that acts like a cushion. On the surface, the skin behaves as a cushion as well, this is because it is made of something considered “thick skin”. The difference between the two is the thickness and make up of the skin. (Thin skin has oil glands, hair, and is o really more stretchy. Skin like the top of your hand, or arm. Try pulling on it, it’s going to stretch and return to it’s natural state, this is useful because it provides flexibility. But thin skin wouldn’t be very useful if there was constant stress on them, like the palm of your hands, or for this example, the heel of the foot. The structure reflects the function of the tissue. Thick skin is more appropriate for this body part since it’s much toucher, and although it isn’t very flexible, it’s a very efficient at protecting these areas from constant stress.) Tl;dr: there are different types of skin, thick and thin, heel has thick skin, thick skin is very good at protecting body
passages: So-called 'traditional' running shoes are designed to give more support and cushion the landing to reduce the effects of impact. They allow for more comfortable running on hard surfaces such as asphalt and also protect the foot when stepping on rocks or other potentially sharp objects. However, the cushioning provided in traditional running shoes is thought to encourage a foot strike pattern, where the heel lands first. Heel striking generates a relatively large amount of impact force that can put different parts of the lower extremities under excessive stress. 
  
  Section::::Footwear.:Barefoot running.
   The beatings are usually aimed at the vaults of the foot, not directly hitting the bone structure of the balls and the heels. The vaults are highly pain-sensitive due to the tight clustering of nerve tissue in that area.
  
  As bastinado usually causes a high amount of suffering for the receiving person while physical evidence remains mostly undetectable after a certain time, it is often used for interrogation purposes in certain countries as well.
  
  Section::::Arts and entertainment.
   A doctor who specializes in the treatment of the feet practices podiatry and is called a podiatrist. A pedorthist specializes in the use and modification of footwear to treat problems related to the lower limbs.
  
  Fractures of the foot include:
  
  BULLET::::- Lisfranc fracture – in which one or all of the metatarsals are displaced from the tarsus
  
  BULLET::::- Jones fracture – a fracture of the fifth metatarsal
  
  BULLET::::- March fracture – a fracture of the distal third of one of the metatarsals occurring because of recurrent stress
  
  BULLET::::- Calcaneal fracture
   Barefoot running has been promoted as one method of reducing the risk of running-related injuries. Barefoot running is thought to improve running form by encouraging forefoot striking. The collision of the forefoot with the ground generates a significantly smaller impact force in comparison to striking heel first. However, barefoot running leaves the foot unprotected from stepping on sharp objects. Although running barefoot may reduce the risk of running-related injuries, it is important to take time while switching from running with shoes. 
   Typically, barefoot walking features heel or midfoot strike, while barefoot running features midfoot or forefoot strike. Barefoot running rarely features heel strike because the impact can be painful, the human heel pad not absorbing much of the force of impact. By contrast, 75% of runners wearing modern running shoes heel strike, running shoes being characterized by a padded sole, stiff soles and arch support, and sloping down from a more padded heel to a less padded forefoot.
   Nerve blocks are performed in a step-wise fashion, beginning at the most distal (lower) part of the limb and moving upward. This is due to the fact that blocking a nerve higher up will desensitize everything it innervates distal to the blocking location. For example, blocking the leg at the level of the fetlock will also block the entire foot, since the nerve fibers that innervate the foot are inhibited when they travel through the fetlock area. A positive result from this block will not be able to differentiate foot pain from pain in the pastern or fetlock region. More information may be gained from blocking the foot first, then the fetlock, since it allows for greater specificity in determining the cause of lameness.
   The cause of this change in gait in shoe running is unknown, but Liebermann noted that there is correlation between the foot-landing style and exposure to shoes. In some individuals, the gait pattern is largely unchanged – the leg position and foot position are identical in barefoot and shoe running – but the wedge shape of the padding moving the point of impact back from the forefoot to the midfoot. In other cases, it is conjectured that the padding of the heel softens the impact and resulting in runner modifying their gait to contact further back in the foot.
   As the disease progresses, the skin may crack, leading to bacterial skin infection and inflammation of the lymphatic vessels. If allowed to grow for too long, athlete's foot fungus may spread to infect the toenails, feeding on the keratin in them, a condition called onychomycosis.
   The calcaneus, also known as the heel bone, is the largest of the tarsal bones and articulates with the cuboid bone anteriorly and the talus bone superiorly. It is responsible for transmitting the majority of the body's weight from the talus bone to the ground.
   Many trail runners use specially designed shoes that have aggressively knobby soles that are generally more rigid than road running shoes. The usually EVA compound midsole often contain a lightweight, flexible nylon plastic layer to protect the feet from puncture wounds from sharp rocks or other objects. Since trail running takes place on softer surfaces (e.g., grass, dirt) than road races, cushioning is not as important so often the shoes are less 'cushioned' than their counterparts designed for tarmac. Additionally, trail running shoes are low to the ground which provides the best stability on uneven terrain. Recently, very thick sole running shoes are gaining popularity especially in Ultra-marathons. In events over 100 miles, they were the most common type of shoe used in 2013.
   The structure of the human foot and lower leg is very efficient at absorbing the shock of landing and turning the energy of the fall into forward motion, through the springing action of the foot's natural arch. Scientists studying runners' foot motions have observed striking differences between habitually shod runners (wearing shoes) and barefoot runners. The foot of habitually shod runners typically lands with an initial heel strike, while the foot of a barefoot runner lands with a more springy step on the middle, or on the ball of the foot. In addition, the strike is shorter in duration and the step rate is higher. When looking at the muscle activity (electromyography), studies have shown a higher pre-activation of the plantar flexor muscles when running barefoot. Indeed, since muscles' role is to prepare the locomotor system for the contact with the ground, muscle activity before the strike depends on the expected impact. Forefoot strike, shorter step duration, higher rate and higher muscle pre-activation are techniques to reduce stress of repetitive high shocks. This avoids a very painful and heavy impact, equivalent to two to three times the body weight. "People who don't wear shoes when they run have an astonishingly different strike", said Daniel E. Lieberman, professor of human evolutionary biology at Harvard University and co-author of a paper appearing in the journal "Nature". "By landing on the middle or front of the foot, barefoot runners have almost no impact collision, much less than most shod runners generate when they heel-strike."
   The "hindfoot" is composed of the talus (or ankle bone) and the calcaneus (or heel bone). The two long bones of the lower leg, the tibia and fibula, are connected to the top of the talus to form the ankle. Connected to the talus at the subtalar joint, the calcaneus, the largest bone of the foot, is cushioned underneath by a layer of fat.
   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 researchers at the Biomechanics Laboratory of the Swiss Federal Institute of Technology, “The least amount of pronation takes place when running barefoot."
  
  Section::::Types.:Supination.
   The running shoe itself has also been examined as a possible cause of many injuries associated with shod running. One 1991 study found that wearers of expensive running shoes that are promoted as having special features, such as added cushioning or "pronation correction", were injured significantly more frequently than runners wearing inexpensive shoes. It has also been found that running in conventional running shoes increases stress on the knee joints up to 38%, although it is still unclear if this leads to a higher rate of heel injuries or not. One study suggests that there is no evidence that cushioning or pronation control in shoes reduces injury rates or reduces performance. It was also found that the belief that one's shoes have increased cushioning had no effect on increasing or decreasing ground reaction forces during walking. Modern running shoes can also increase joint torque at the hip, knee, and ankle, and the authors of the study even suggest that running in high heels might be better than modern running shoes. Improperly fitting shoes may also result in injuries such as a subungual hematoma – a collection of blood underneath the toenail. This may also be known as "runner's toe" or "tennis toe". However, a recent randomized controlled trial (RCT) suggested that heavier runners might be at an increased risk for injury in minimalist shoes (designed to mimic barefoot running) as compared to conventional footwear.
   Barefoot runners run very differently from typical shod runners. Shod runners tend to heel strike due to the designs of the modern shoes, which have thick heels to reduce the impact force from the ground. When running barefoot, however, some runners tend to shift to a forefoot striking pattern to avoid such impact, which is equivalent to 2-3 times the body weight. The forefoot strike is where the forefoot lands first, followed by the heels coming down. The midfoot strike is characterized by the heel and the ball of the foot landing at the same time, and heel strike is where the heel lands first followed by the forefoot. 
   The navicular bone in humans is located on the medial side of the foot, and articulates proximally with the talus, distally with the three cuneiform bones, and laterally with the cuboid.
  
  It is the last of the foot bones to start ossification and does not tend to do so until the end of the third year in girls and the beginning of the fourth year in boys, although a large range of variation has been reported.
   Unfortunately, the prevention of falls and automobile accidents is limited and applies to unique circumstances that should be avoided. The risk of muscular stress fractures can be reduced through stretching and weight-bearing exercise, such as strength training. In addition, footwear can influence forces that may cause a calcaneal fracture and can prevent them as well. A 2012 study conducted by Salzler showed that the increasing trend toward minimalist footwear or running barefoot can lead to a variety of stress fractures including that of the calcaneus.
  
  Section::::Cause.:Osteoporosis.
   However, even among elite athletes there are variations in self selected footstrike types. This is especially true in longer distance events, where there is a prevalence of heel strikers. There does tend however to be a greater percentage of mid/forefoot striking runners in the elite fields, particularly in the faster racers and the winning individuals or groups. While one could attribute the faster speeds of elite runners compared to recreational runners with similar footstrikes to physiological differences, the hip and joints have been left out of the equation for proper propulsion. This brings up the question as to how heel striking elite distance runners are able to keep up such high paces with a supposedly inefficient and injurious foot strike technique.
   Section::::Barefoot (unshod).:Impact forces.
  
  In barefoot locomotion, the impact force (impact transient) on the ground is diminished compared to shod running. It has been suggested that unshod runners are better able to take advantage of elastic energy storage in the Achilles tendon and arch of the foot, and can avoid potential injury due to repetitive impact of the heel bone (calcaneus) due to heel striking. However, the long-term and actual health benefits of unshod running are still not well understood and remain an area of active research.
   BULLET::::- Patient can have enthesitis presenting as heel pain, Achilles tendinitis or plantar fasciitis, along with balanitis circinata (circinate balanitis), which involves penile lesions present in roughly 20 to 40 percent of the men with the disease.
  
  BULLET::::- A small percentage of men and women develop small hard nodules called keratoderma blennorrhagicum on the soles of the feet and, less commonly, on the palms of the hands or elsewhere. The presence of keratoderma blennorrhagica is diagnostic of reactive arthritis in the absence of the classical triad. Subcutaneous nodules are also a feature of this disease.
   Runner's toe is often associated with malfitting shoes and insufficient space for the toes. Some susceptible runners may also have Morton's toe. In this variant of human foot anatomy, the second toe extends further out than the great toe. The key to prevention of runner's toe is to purchase properly fitted shoes.
   Plantar athlete's foot (moccasin foot) is also caused by "T. rubrum" which typically causes asymptomatic, slightly erythematous plaques (areas of redness of the skin) to form on the plantar surface (sole) of the foot that are often covered by fine, powdery hyperkeratotic scales.
   Medical imaging is not routinely needed as it is expensive and does not typically change how plantar fasciitis is managed. When the diagnosis is not clinically apparent, lateral view x-rays of the ankle are the recommended imaging modality to assess for other causes of heel pain such as stress fractures or bone spur development.
   Nearly half of all vertebral fractures occur without any significant back pain. If pain medication, progressive activity, or a brace or support does not help with the fracture, two minimally invasive procedures - vertebroplasty or kyphoplasty - may be options.
  
  Ankles can be stabilized by lightweight orthoses, available in molded plastics as well as softer materials that use elastic properties to prevent foot drop. Additionally, shoes can be fitted with traditional spring-loaded braces to prevent foot drop while walking. Regular exercise is usually prescribed.
   However, when comparing different populations of habitually barefoot runners, not all of them favor the forefoot strike. A 2012 study by Hatala et al. focusing on 38 runners of the Daasanach tribe in Kenya found that a majority of runners favored a heel strike instead of a forefoot strike. Presently, Hatala and Lieberman are comparing their data, but Lieberman did note that his study, which focused on the Kalenjin people, also found some barefoot runners favoring a heel strike as well. He also said that the Daasanach people were primarily, "tall, lanky goat-herders who don't run nearly as much as the Kalenjin, who own many of the world's distance running records."
  
presuppositions: The bone on our heel should poke through the skin when you run a marathon.
corrections: The heel bone will not poke through the skin when running, due to the thick layer of fatty tissue cushioning it.
raw_presuppositions: The bone on our heel should poke through the skin when you run a marathon. The bone on our heel should poke through the skin when you run a marathon.
raw_corrections: The heel bone will not poke through the skin when running, due to the thick layer of fatty tissue cushioning it. The heel bone will not poke through the skin when running, due to the thick layer of fatty tissue cushioning it.