Materiały źródłowe

• #1 Stress fracture – Wikipedia

  https://en.wikipedia.org/wiki/Stress_fracture

  A stress fracture is a fatigue-induced bone fracture caused by repeated stress over time. Instead of resulting from a single severe impact, stress fractures are the result of accumulated injury from repeated submaximal loading, such as running or jumping. Because of this mechanism, stress fractures are common overuse injuries in athletes. […] Bones are constantly attempting to remodel and repair themselves, especially during a sport where extraordinary stress is applied to the bone. Over time, if enough stress is placed on the bone that it exhausts the capacity of the bone to remodel, a weakened site a stress fracture may appear on the bone. The fracture does not appear suddenly. It occurs from repeated traumas, none of which is sufficient to cause a sudden break, but which, when added together, overwhelm the osteoblasts that remodel the bone.

• #1 Stress Fractures: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/1270244-overview

  Oh et al proposed the following classification of stress fractures into four types, adding atypical fractures to the traditional three types: Fatigue fractures – These are due to overuse of bone with normal elastic resistance, Insufficiency fractures – These are due to everyday physiologic stress on fragile bone with poor elastic resistance, Pathologic fractures – These are due to bone weakness involving tumors, Atypical fractures.

• #1

  https://journals.lww.com/acsm-csmr/fulltext/2017/01000/stress_fractures.5.aspx

  Bone normally responds to muscle pull (direction, intensity) or impact shock by deforming and then returning to normal shape (6). […] A complete cycle of bone turnover and remodeling and mineralization requires 3 to 4 months. When bone cannot remodel at the pace at which loading increases, the bone fractures (1). […] Wolffs law applies to bone: As stress on bone increases, the bone deforms to accept the given force until the force exceeds bones elastic range, at which time permanent damage, like microfracture, occurs (3).

• #1 Stress Fractures – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554538/

  Repetitive loading will stimulate osteoclasts to resorption at a faster rate than osteoblasts can form new bone. The normal cycle of remodeling takes 3 to 4 months. […] Osteocytes, through a dense dendritic network, respond to biomechanical stress. These cells secrete mediators that regulate osteoblast and osteoclast activity. It appears cyclic loading can cause the normal dendritic processes of osteocyte signaling to be compromised and thus leads to the impeding the physiological mechanisms of repair.

• #1 Stress Fracture of the Hip | PM&R KnowledgeNow

  https://now.aapmr.org/stress-fracture-of-the-hip/

  Wolffs law states that normal stress placed on normal bone produces normal remodeling of the bone. If sufficient time is allowed for remodeling and the load applied does not exceed the strength of the bone structure, the bone becomes stronger. […] Remodeling begins with osteoclastic resorption of bone and is followed by osteoblastic new bone formation. Osteoclastic resorption weakens the bone; if insufficient time is allowed for new bone formation, microfractures occur which can progress to stress reaction and eventual fracture. The resorption phase peaks at about 3 weeks; but the normal duration for the complete remodeling process is 3 months. […] Repetitive loading of bone in the context of insufficient time for new bone formation produces an environment in which resorption predominates, leading to weakening of the bone. The process of fatigue fracture begins with crack initiation which progresses to crack propagation and eventual complete fracture unless the conditions which precipitated the problem are altered to allow resumption of normal remodeling of bone.

• #1 Mechanisms and Management of Stress Fractures in Physically Active Persons

  https://pmc.ncbi.nlm.nih.gov/articles/PMC164361/

  The result is a weakened bone that is less able to withstand subsequent loads. […] Stress fractures can occur to just about any bone in a physically active person. They are at the endpoint of a continuum of a bone’s reaction to stress that ranges from early remodeling to a cortical fracture. Normal levels of stress facilitate normal bone remodeling. When activity levels change or increase, the level of bone remodeling also increases. A gradual decrease in bone density follows this higher level of remodeling and places the bone at risk for a stress fracture.

• #1 Stress Fracture: A Review of the Pathophysiology, Epidemiology and Management Options

  https://www.jscimedcentral.com/jounal-article-info/Journal-of-Fractures-and-Sprains/Stress-Fracture%3A-A-Review-of-the–Pathophysiology%2C-Epidemiology–and-Management-Options-10338

  Stress fractures are considered to require some of the longest recovery times of all MSKI. […] It is well recognized that the pathogenesis of stress fracture is multifactorial in nature; however, the precise mechanisms are yet to be confirmed and so remain theoretically proposed. […] The precise pathophysiological mechanisms involved with the development of stress fractures are not fully understood. […] The underlying cause of stress fracture is the inability of the remodeling process to sustain the physiological stress applied through repetitive mechanical loading. […] Development of Stress fracture has also been attributed to oxidation deprivation, a bi-product of repeated mechanical compressive load which leads to transient ischemia in the weight-bearing bones. […] The exact mechanism is unknown, however two main theories are proposed across the literature. These are the piezoelectric charge theory and the Hueter-Volkmann law.

• #1 Mechanisms and Management of Stress Fractures in Physically Active Persons

  https://pmc.ncbi.nlm.nih.gov/articles/PMC164361/

  The piezoelectric effect is one mechanism implicated in the activation of bone remodeling. Tension forces create a relative electropositivity on the convex, or tension side, of the bone. This increase in positive charge is conducive to osteoclastic resorption. […] The temporary lack of oxygen is not the only cause of ischemia. Repeated pressure to the capillaries is also believed to cause microdamage to the vessels. […] The repetition of this cycle causes an increase in remodeling, a breakdown in the cortex, a weakening of the bone, and potentially a stress fracture. […] The fatigue fracture is caused by an abnormal stress to a normally elastic bone. […] Until recently, the cause of stress fractures was thought to be due to the breakdown of bone after repetitive loading. […] Otter et al proposed that the perfusion and reperfusion of bone after a repetitive load causes a temporary oxygen debt to the area of bone being stressed.

• #1 The Radiology Assistant : Stress fractures

  https://radiologyassistant.nl/musculoskeletal/unsorted/stress-fractures

  A stress fracture is an overuse injury. Bone is constantly attempting to remodel and repair itself, especially when extraordinary stress is applied. When enough stress is placed on the bone, it causes an imbalance between osteoclastic and osteblastic activity and a stress fracture may appear. […] Muscle fatigue can also play a role in the occurrence of stress fractures. For every mile a runner runs, more than 110 tons of force must be absorbed by the legs. Bones are not made to withstand so much energy on their own and the muscles act as shock absorbers. As muscles become tired and stop absorbing, all forces are transferred to the bones. […] Stress fractures usually occur after a recent change in training regimen has taken place. Especially professional or recreational athletes and military recruits are subject to change in training intensity (increased), type of training or training circumstances (new shoes, other training surface etc.) and thus at increased risk of developing a stress fracture. However, sedentary people may also develop stress fractures if suddenly an active lifestyle is adopted.

• #1 SciELO Brazil – Stress fractures: definition, diagnosis and treatment Stress fractures: definition, diagnosis and treatment

  https://www.scielo.br/j/rbort/a/7V8g8ygyjRWtdd3DkKSrkcb/

  The load applied is considered to be insufficient to cause an acute fracture, but the combination of overloading, repetitive movements and inadequate recovery time make this a chronic injury. […] Elastic deformation occurs initially, and this progresses to plastic deformity until it finally results in microfracturing. If this is not treated, it will evolve to complete fracturing of the bone affected. […] The bone repair process in stress fractures differs from the process in cases of common acute fractures and only takes place through bone remodeling, i.e. reabsorption of the injured cells and replacement with new bone tissue take place. […] Markey also proposed that the muscle mass acts toward dispersing and sharing impact loads on the bone tissue. Therefore, when fatigue, weakness or muscle unpreparedness occur, this protective action is lost and the risk of bone tissue lesions increases.

• #1 Stress Fractures : Wheeless’ Textbook of Orthopaedics

  https://www.wheelessonline.com/trauma-fractures/stress-fractures/

  – occur as the result of repetitive loading below yeild strength are most common in lower extremity (metatarsals calcaneus tibia); […] – focal structural muscle weakness repetitive muscle pull are common; […] – common in athletes, esp in white women, with advancing age, and w/ underlying metabolic bone diseases; […] – progression of stress fractures: – stage I – crack initiation: areas of stress concentration – stage II – crack propagation: no repair or more damage than repair – stage III – final fracture: cracks coalesce, enlarge, ultimate failure […] – risk factors: pronated feet, cavus feet, and increased external tibial torsion are common risk factors; […] – Epidemiology of metatarsal stress fractures versus tibial and femoral stress fractures during elite training.

• #1 Stress Fractures: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/15841-stress-fractures

  Stress fractures start as inflammation on a bones surface (healthcare providers call this a stress reaction). Stress reactions are like deep bone bruises. If something keeps putting pressure on that same spot before the stress reaction can heal, your bone can crack and create a stress fracture. The bruise will reach deeper into the bone over time until it makes it weak enough to break. Thats when a stress reaction becomes a stress fracture.

• #1 Stress fracture in sports https://static.wixstatic.com/media/23ac3b_bbbeefac2b1b48618afff65773d211b8~mv2.jpg/v1/fill/w_713,h_206,al_c,lg_1,q_80/23ac3b_bbbeefac2b1b48618afff65773d211b8~mv2.jpg

  https://www.breathephysio.com/post/stress-fracture-in-sports

  Stress fracture describes either a partial or complete fracture of the bone. […] Due to the mechanism of this injury, stress fractures are more commonly found in weight-bearing limbs such as your tibia (shin bone), metatarsals (foot) and fibula (next to your shin bone). […] Crack initiation typically occurs at the site of stress concentration during bone loading. […] Crack propagation when abnormal force continued to apply to the bone, disrupting the homeostasis at which the rate of new bone laying down and microcracks repair is below the rate of stress applied. […] Complete fracture when continued and increased load is not met with increased reparative process reaching a point of structural failure and partial and complete fractures occur. […] Insufficiency fracture is typically due to abnormal bone health. […] Thus, people who suffer from osteopenia or osteoporosis are more prone to insufficiency fractures.

• #1 Stress Reaction and Fractures | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/29541

  Stress fractures result from repeated submaximal loading. […] An imbalance between osteoclast and osteoblast activity triggers microdamage accumulation. […] Stress reactions and fractures result from repetitive microtrauma rather than acute injuries. […] Stress fractures are common among runners and military recruits, often associated with changes in training intensity, footwear, or surfaces. […] Certain structural or gait abnormalities (eg, cavovarus foot alignment or narrow tibial width) may increase stress on specific bones. […] In normal healthy bone, osteoblastic activity repairs microdamage caused by regular physical activity. A stress fracture occurs when osteoclastic resorption exceeds osteoblastic repair, causing structural weakness. […] Biomechanical factors also influence stress fracture development.

• #1 Mechanisms and Management of Stress Fractures in Physically Active Persons

  https://pmc.ncbi.nlm.nih.gov/articles/PMC164361/

  Bone undergoes a normal remodeling process in physically active persons. Increased stress leads to an acceleration of this remodeling process, a subsequent weakening of bone, and a higher susceptibility to stress fracture. […] Stress fractures occur as the result of increased remodeling and a subsequent weakening of the outer surface of the bone. […] A stress fracture is a partial or incomplete fracture caused by the accumulation of stress to a localized area of bone. Stress fractures are not the result of one specific insult. Instead, they arise as the result of repetitive applications of stresses that are lower than the stress required to fracture the bone in a single loading. […] Bone constantly remodels itself to more efficiently endure external forces. Remodeling involves the resorption of existing bone by osteoclasts and the formation of new bone cells by osteoblasts.

• #1 Stress Fractures: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/1270244-overview

  Stress fractures result from recurrent and repetitive loading of bone. The stress fracture differs from other types of fractures in that in most cases, no acute traumatic event precedes the symptoms. […] A stress fracture is caused by repetitive and submaximal loading of the bone, which eventually becomes fatigued and leads to a true fracture. […] Stress fractures develop when extensive microdamage occurs before the bone can be adequately remodeled. […] The three factors that can predispose an individual to the development of stress fractures are as follows: Increase in the applied load, Increase in the number of applied stresses, Decrease in the surface area of the applied load. […] The applied load on the bone may be increased by decreasing the surface area across which the weight is distributed or by increasing the total weight that is applied to the bone. High-impact activities, such as jumping or performing plyometrics, running on a new surface, or practicing incorrect biomechanical movements or techniques, may increase the risk of stress fractures.

• #1 Stress Fractures of the Foot and Ankle – OrthoInfo – AAOS

  https://orthoinfo.aaos.org/en/diseases–conditions/stress-fractures-of-the-foot-and-ankle/

  Doing „too much, too soon” is a common cause of stress fracture. […] Anything that alters the mechanics of how your foot absorbs impact as it strikes the ground may increase your risk for a stress fracture. […] A change in training or playing surface can increase the risk for stress fracture. […] Wearing worn or flimsy shoes that have lost their shock-absorbing ability may contribute to stress fractures.

• #1 Stress fracture – Wikipedia

  https://en.wikipedia.org/wiki/Stress_fracture

  Muscle fatigue can also play a role in the occurrence of stress fractures. In a runner, each stride normally exerts large forces at various points in the legs. Each shock a rapid acceleration and energy transfer must be absorbed. Muscles and bones serve as shock absorbers. However, the muscles, usually those in the lower leg, become fatigued after running a long distance and lose their ability to absorb shock. As the bones now experience larger stresses, this increases the risk of fracture. […] Previous stress fractures have been identified as a risk factor. Along with history of stress fractures, a narrow tibial shaft, high degree of hip external rotation, osteopenia, osteoporosis, and pes cavus are common predisposing factors for stress fractures. […] Common causes in sport that result in stress fractures include: Over training, Going back to competition too soon after an injury or illness, Going from one event to another without proper training for the second event, Starting initial training too quickly, Changing habits or the environment like training surface or shoes.

• #1 1 Pathophysiology and Epidemiology of Stress Fractures in Military Women | Reducing Stress Fracture in Physically Active Military Women | The National Academies Press

  https://nap.nationalacademies.org/read/6295/chapter/3

  The dynamic processes involved in bone metabolism relate to the events associated with bone formation and bone resorption. […] A large number of modulators, including hormones, growth factors, and cytokines, interact at the level of the osteoblast, osteoclast, and other cells to regulate bone remodeling (Margolis et al., 1996). […] Systemic hormones that either regulate calcium balance or affect bone remodeling include parathyroid hormone, calcitonin, vitamin D, estrogen, progesterone, growth hormone (GH), thyroid hormone, glucocorticoids, and androgens. […] Repetitive loads to bone applied below the load required for single cycle failure (the load that would break bone with a single application) produce cumulative microdamage and initiate the process of accelerated remodeling. […] The main functions of remodeling are to adapt bone to mechanical loading, to prevent the accumulation of microfractures or fatigue damage (Marcus, 1991; Parfitt, 1988), and to maintain blood calcium levels.

• #1

  https://link.springer.com/article/10.1007/s11914-996-0029-y

  Study investigating the dose-response relationship between energy availability and selected markers of bone turnover in female military recruits. Bone formation markers decreased and bone resorption markers increased in those who had restricted energy availability, suggesting that nutritional status may contribute to the higher incidence of stress fractures in female military recruits.

• #1 1 Pathophysiology and Epidemiology of Stress Fractures in Military Women | Reducing Stress Fracture in Physically Active Military Women | The National Academies Press

  https://nap.nationalacademies.org/read/6295/chapter/3

  The clinical response of bone to load can be seen along a continuum from accelerated remodeling to a complete fracture. […] The presence of estrogen stimulates GH secretion and potentiates the anabolic effect of GH by upregulating GH-receptors on the osteoblast (Slootweg et al., 1997). […] A stress fracture occurs when changes in physical activity produce a site-specific mechanical ”load.” […] This load results in an acute imbalance between the rate of osteoclastic resorption and the rate of osteoblastic new bone formation. […] Stress fractures are diagnosed using a combination of clinical symptoms and results from bone imaging studies. […] Stress fractures are more common in military women than in men, with estimates in women being 1.2 to 11 times higher than in men in the various studies performed to date. […] Female military trainees appear to be more likely to suffer stress fractures in the upper leg and pelvis than are males. […] These fractures are more costly in terms of rehabilitation and potential disability than those that occur in the lower leg.

• #1 What Is A Stress Fracture? Podiatric Clinic St-Charles

  https://st-charlespodiatrie.com/en-ca/2025/02/06/what-is-a-stress-fracture/

  A stress fracture, also known as a fatigue fracture, occurs when bonesespecially in weight-bearing areas like the tibia and footexperience continuous and repetitive stress. This type of fracture develops when intense physical activities exert excessive pressure on the bones, surpassing their natural ability to regenerate. For instance, female athletes, particularly runners, face a higher risk due to the constant impact on their feet and tibias. […] Hormonal Imbalances: Female athletes may be more susceptible due to hormonal fluctuations affecting bone density, such as those associated with amenorrhea or the female athlete triad. […] In many cases, stress fractures arise when an athlete suddenly increases the intensity or duration of training without allowing the body adequate time to adapt. Young female athletes in high-intensity sports should be mindful of their limits and ensure they get sufficient rest.

• #1

  https://link.springer.com/article/10.1007/s10140-016-1390-5

  Stress fracture, in its most inclusive description, includes both fatigue and insufficiency fracture. Fatigue fractures, sometimes equated with the term stress fractures, are most common in runners and other athletes and typically occur in the lower extremities. These fractures are the result of abnormal, cyclical loading on normal bone leading to local cortical resorption and fracture. Insufficiency fractures are common in elderly populations, secondary to osteoporosis, and are typically located in and around the pelvis. They are a result of normal or traumatic loading on abnormal bone. […] Imaging recommendations for evaluation of stress fractures include initial plain radiographs followed, if necessary, by magnetic resonance imaging (MRI), which is preferred over computed tomography (CT) and bone scintigraphy. Radiographs are the first-line modality and may reveal linear sclerosis and periosteal reaction prior to the development of a frank fracture. MRI is highly sensitive with findings ranging from periosteal edema to bone marrow and intracortical signal abnormality.

• #1 Stress Fractures – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554538/

  Stress fractures occur when bone, typically in the lower extremities, is subjected to repeated mechanical stress that results in microscopic fractures. […] Stress fractures can be classified as fatigue reaction stress fractures or insufficiency reaction stress fractures. Fatigue reaction stress fractures result from repetitive and excessive strain placed on structurally normal bone, specifically loading, exceeding the process of remodeling. Whereas insufficiency reaction stress fracture occurs when normal stress and straining are applied to a bone where bone formation is impaired. […] A stress fracture occurs when the adaptive ability of the bone is unbalanced. Normal bone is constantly being remodeled by osteoclasts absorbing and osteoblasts laying down new bone. During military training, for instance, the body cannot adapt fast enough, so the bone develops microfractures.

• #1 Models for the pathogenesis of stress fractures in athletes. | British Journal of Sports Medicine

  https://bjsm.bmj.com/content/30/3/200

  It would seem that the development of a stress fracture results from unsuccessful adaptation of bone to a change in its mechanical environment caused by repetitive loading. It involves the physiological processes of microdamage production and remodelling. Whether the initiating factor is microdamage production or activation of remodelling through direct effects of strain is unclear. The remodelling process involves both the removal of bone which has become fatigue damaged or is extraneous to the requirements of the new loading environment, and the addition of new bone in a manner that is best suited to withstand the new mechanical strain. Normally this process is well modulated and does not cause symptoms. If the amount of bone removed is not sufficient to unduly weaken bone structure and the addition of new bone occurs sufficiently rapidly to correct any weakness before failure occurs or to repair microdamage, the process will successfully lead to a bone with appropriate material strength and geometry to withstand the new strain environment. However, if there is imbalance between bone removal and replacement, together with accumulation of microdamage, signs and symptoms of a stress fracture may result. Any factors which influence bone load, bone strength, or remodelling have the potential to result in a stress fracture. Attention should be paid to the identification of these factors in an attempt to prevent this overuse injury in athletes.

• #1 Stress Fractures: Diagnosis, Treatment, and Prevention | AAFP

  https://www.aafp.org/pubs/afp/issues/2011/0101/p39.html

  Stress fractures are common injuries that begin with repetitive and excessive stress on the bone. This leads to the acceleration of normal bone remodeling, the production of microfractures (caused by insufficient time for the bone to repair), the creation of a bone stress injury (i.e., stress reaction), and, eventually, a stress fracture. […] Stress fractures should be considered in patients who present with tenderness or edema after a recent increase in activity or repeated activity with limited rest. […] Treatment of stress fractures consists of activity modification, including the use of nonweight-bearing crutches if needed for pain relief. […] Surgical consultation may be appropriate for patients with stress fractures in high-risk locations, nonunion, or recurrent stress fractures. […] Prevention of stress fractures has been studied in military personnel, but more research is needed in other populations.

• #1 Stress Fracture: A Review of the Pathophysiology, Epidemiology and Management Options

  https://www.jscimedcentral.com/jounal-article-info/Journal-of-Fractures-and-Sprains/Stress-Fracture%3A-A-Review-of-the–Pathophysiology%2C-Epidemiology–and-Management-Options-10338

  The stress fracture represents a point in the continuum where a stress response to applied load starts as silent micro-damage. […] Stress fractures occur most commonly in the lower limb, a consequence of repetitive high impact activities such as jogging, running or hopping. […] The neuro-muscular system also considered to play a key role in the pathophysiology of stress fractures. […] The Professional, legal and moral responsibility to investigate causation, management and mitigation of these costly injuries is the property of both organisation and individual clinician. […] The purpose of this review is to present an overview of the pathogenesis, epidemiology and provide a brief overview of management perspectives.

• #2 Stress Fractures – The Foot Doctor – Dr. Ronald Gmerek

  https://www.therochesterfootdoctor.com/stress-fractures.html

  Also known as a hairline fracture, is a fatigue-induced fracture of the bone caused by repeated stress over time. Instead of resulting from a single severe impact, stress fractures are the result of accumulated trauma from repeated submaximal loading, such as running or jumping. Because of this mechanism, stress fractures are common overuse injuries in athletes. Stress fractures can be described as a very small sliver or crack in the bone; and are sometimes referred to as „hairline fractures”. Stress fractures most frequently occur in weight-bearing bones, such as the tibia (bone of the lower leg), metatarsals, and navicular bones (bones of the foot). Less common are fractures to the femur, pelvis, and sacrum. […] Bones are constantly attempting to remodel and repair themselves, especially during a sport where extraordinary stress is applied to the bone. Over time, if enough stress is placed on the bone that it exhausts the capacity of the bone to remodel, a weakened site a stress fracture on the bone may appear. The fracture does not appear suddenly. It occurs from repeated traumas, none of which is sufficient to cause a sudden break, but which, when added together, overwhelm the osteoblasts that remodel the bone.

• #2

  https://www.orthobullets.com/evidence/27002328

  Stress fracture, in its most inclusive description, includes both fatigue and insufficiency fracture. Fatigue fractures, sometimes equated with the term „stress fractures,” are most common in runners and other athletes and typically occur in the lower extremities. These fractures are the result of abnormal, cyclical loading on normal bone leading to local cortical resorption and fracture. […] Insufficiency fractures are common in elderly populations, secondary to osteoporosis, and are typically located in and around the pelvis. They are a result of normal or traumatic loading on abnormal bone. […] Medial tibial stress syndrome is a type of stress injury of the tibia related to activity and is a clinical syndrome encompassing a range of injuries from stress edema to frank-displaced fracture.

• #2 1. stress fractures | PPT

  https://www.slideshare.net/slideshow/1-stress-fractures/24501400

  Stress fractures occur when normal bone is exposed to abnormal stress over time. They are common in military personnel and athletes. […] Stress fractures occur when normal bone is exposed to abnormal stress. They are seen in professional athletes and in military personnel. Insufficiency fractures are fractures which occur in abnormal bone when exposed to a normal stress. They most commonly occur secondary to untreated osteoporosis. […] Bone is a dynamic tissue constantly remodelling under the influence of multiple hormonal and mechanical factors. There is a balance between bone resorption, carried out by osteoclasts, and bone synthesis, carried out by osteoblasts. Bone has a remodelling response to mechanical stress so that the greatest amount of bone is laid down in areas of greatest applied stress (Wolffs Law).

• #2 Mechanisms and Management of Stress Fractures in Physically Active Persons

  https://pmc.ncbi.nlm.nih.gov/articles/PMC164361/

  Bone undergoes a normal remodeling process in physically active persons. Increased stress leads to an acceleration of this remodeling process, a subsequent weakening of bone, and a higher susceptibility to stress fracture. […] Stress fractures occur as the result of increased remodeling and a subsequent weakening of the outer surface of the bone. […] A stress fracture is a partial or incomplete fracture caused by the accumulation of stress to a localized area of bone. Stress fractures are not the result of one specific insult. Instead, they arise as the result of repetitive applications of stresses that are lower than the stress required to fracture the bone in a single loading. […] Bone constantly remodels itself to more efficiently endure external forces. Remodeling involves the resorption of existing bone by osteoclasts and the formation of new bone cells by osteoblasts.

• #2 Stress fractures – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/stress-fractures/symptoms-causes/syc-20354057

  Stress fractures are tiny cracks in a bone. Repeated stress to the bone causes them. The stress often comes from using the same body part too much. […] Stress fractures often happen when you increase the amount or intensity of an activity too fast. Bone can adapt to greater amounts of stress, but it needs time to do so. During a lifelong process called remodeling, old bone tissue is destroyed and then rebuilt. This process speeds up when the weight-bearing load on the bone increases. The risk of a stress fracture rises when a bone bears an unusual amount of force without enough time to recover. Bone tissue is destroyed faster than the body can replace it.

• #2 Pathophysiology and Epidemiology of Stress Fractures | Musculoskeletal Key

  https://musculoskeletalkey.com/pathophysiology-and-epidemiology-of-stress-fractures/

  Stress fracture constitutes a spectrum of injury that includes bone strain, stress reaction, and stress fracture. The etiology is repetitive loading in the setting of inadequate bone remodeling. […] When stress is applied to bone, Wolffs law dictates that bone will remodel in response to mechanical stress. The exact method by which bone remodels is not truly understood, but two theories predominate. In the piezoelectric charge theory, tensile-sided strain is said to create electropositive forces that stimulate osteoclastogenesis, while the compression side is subject to electronegative forces that stimulate osteoblastogenesis. […] Stress injury may also occur with normal strain, but this is typically in the setting of depressed bone remodeling. These injuries are known as insufficiency reactions or fractures.

• #2 Pathophysiology and Epidemiology of Stress Fractures | Musculoskeletal Key

  https://musculoskeletalkey.com/pathophysiology-and-epidemiology-of-stress-fractures/

  Another special consideration in the pathophysiology of stress fractures in athletes is the influence of skeletal muscle. Muscles may protect the tibia during running by producing shear forces that counteract the joint reaction forces and result in reduced net shear stresses in the tibia. […] Finally, there is an oxidation deprivation theory of stress fracture development, which deserves some attention. In this theory, the repeated load of an activity such as running is thought to cause decreased oxygen delivery and brief ischemia in weight-bearing bones. […] Bone stress injury occurs via an imbalance of repetitive stress and normal bone remodeling/recovery in response to that stress. Although the paradigms of fatigue failure (high stress overwhelming normal turnover) and insufficiency failure (normal stress overwhelming disordered turnover) are a simple means of conceptualizing this disorder.

• #2 Stress Fractures – The Foot Doctor – Dr. Ronald Gmerek

  https://www.therochesterfootdoctor.com/stress-fractures.html

  Muscle fatigue can also play a role in the occurrence of stress fractures. In a runner, each stride normally exerts large forces at various points in the legs. Each shock a rapid acceleration and energy transfer must be absorbed. Both muscles and bones serve as shock absorbers. However, the muscles, usually those in the lower leg, become fatigued after running a long distance and lose their ability to absorb shock. As the bones now experience larger stresses, this increases the risk of fracture. […] Previous stress fractures have been identified as a risk factor. […] One method of avoiding stress fractures is to add more stress to the bones. Though this may seem counter-intuitive (because stress fractures are caused by too much stress on the bone), moderate stress applied to the bone in a controlled manner can strengthen the bone and make it less susceptible to a stress fracture.

• #2 Stress Fractures: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/15841-stress-fractures

  Stress fractures start as inflammation on a bones surface (healthcare providers call this a stress reaction). Stress reactions are like deep bone bruises. If something keeps putting pressure on that same spot before the stress reaction can heal, your bone can crack and create a stress fracture. The bruise will reach deeper into the bone over time until it makes it weak enough to break. Thats when a stress reaction becomes a stress fracture.

• #2 Stress fracture in sports https://static.wixstatic.com/media/23ac3b_bbbeefac2b1b48618afff65773d211b8~mv2.jpg/v1/fill/w_713,h_206,al_c,lg_1,q_80/23ac3b_bbbeefac2b1b48618afff65773d211b8~mv2.jpg

  https://www.breathephysio.com/post/stress-fracture-in-sports

  Stress fracture describes either a partial or complete fracture of the bone. […] Due to the mechanism of this injury, stress fractures are more commonly found in weight-bearing limbs such as your tibia (shin bone), metatarsals (foot) and fibula (next to your shin bone). […] Crack initiation typically occurs at the site of stress concentration during bone loading. […] Crack propagation when abnormal force continued to apply to the bone, disrupting the homeostasis at which the rate of new bone laying down and microcracks repair is below the rate of stress applied. […] Complete fracture when continued and increased load is not met with increased reparative process reaching a point of structural failure and partial and complete fractures occur. […] Insufficiency fracture is typically due to abnormal bone health. […] Thus, people who suffer from osteopenia or osteoporosis are more prone to insufficiency fractures.

• #2 SciELO Brasil – Stress fractures Stress fractures

  https://www.scielo.br/j/aem/a/xXnv9wtXcGm8FqVN5tDsYzd/?lang=en

  Stress fractures (SFs) occur when abnormal and repetitive loading is applied on normal bone: The body cannot adapt quickly enough, leading to microdamage and fracture. […] SFs reflect an imbalance between bone strength and the mechanical load placed upon the bone. When abnormal stress is applied to a normal bone, a fatigue fracture can occur, but when normal stress is applied to an abnormal bone, an insufficiency fracture occurs. […] SFs are the result of a disbalance between the remodeling and microdamage, leading to inadequate repair and cumulative damage, with predominance of osteoclastic activity over osteoblastic activity and new bone formation. […] Understanding better the pathophysiology of SFs and the potential utility of current and future bone-active therapeutics may well yield approaches that could treat SFs more effectively.

• #2

  https://journals.lww.com/sjsm/fulltext/2017/17010/common_stress_fractures_in_runners__an_analysis.1.aspx

  Stress fractures are common injuries in both professional and recreational runners. This type of injury occurs more frequently in the lower extremities and can be caused by a number of both extrinsic and intrinsic factors. […] It is believed that numerous factors contribute to the development of the pathogenesis of stress fractures in runners. These factors are typically grouped into two major categories; extrinsic and intrinsic risk factors. […] Most of the stress fractures develop gradually and usually occur as a result of repetitive overload and/or overuse of the bone, when mechanical stresses exceed bone remodeling and adaptive capacity. […] It is well documented that the risk of developing a stress fracture is influenced by many factors, categorized as intrinsic and extrinsic factors. In this multifactorial etiology of stress fracture, some alteration in training regimen seems to play a central and crucial role.

• #2

  https://link.springer.com/article/10.1007/s11914-996-0029-y

  Study investigating the dose-response relationship between energy availability and selected markers of bone turnover in female military recruits. Bone formation markers decreased and bone resorption markers increased in those who had restricted energy availability, suggesting that nutritional status may contribute to the higher incidence of stress fractures in female military recruits.

• #2 Stress Fracture of the Hip | PM&R KnowledgeNow

  https://now.aapmr.org/stress-fracture-of-the-hip/

  Stress fractures are common injuries that tend to occur in athletes or other people who participate in activities that place repetitive and excessive stress on bone. They are part of a continuum of injuries which is broadly classified as bone stress injury (BSI). BSI represents the inability of bone to withstand repetitive loading leading to structural fatigue and microarchitectural discontinuities. BSI initially starts as a stress reaction which can progress to stress fracture and finally a complete bone fracture. Stress fractures can be further broken down based upon whether they occur as the result of excessive and repetitive strain placed on structurally normal bone (fatigue reaction) or normal stress applied to structurally abnormal bone (insufficiency reaction). […] Stress fractures are often multifactorial and common risk factors include high volume of activity, anatomic changes, poor preparticipation fitness, low bone mineral density, and prior history of stress fracture. Fatigue fractures occur when continued repetitive loading exceeds the process of remodeling. Insufficiency fractures occur when normal loading is applied to bone in which new bone formation is impaired, producing reduced mechanical strength. Insufficiency or pathological fractures include those that occur in bone weakened by infection, tumor, or various processes producing low bone mineral density.

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