Facts that bones remodel throughout your entire life

FACT #1: Limb lengthening surgery is an excellent example to prove that bones remodel, re-build, grow, thicken, and lengthen due to a stretching force (either by bone growth electric stimulator, or by heavy ankle weights).FACT #2: The Padung or “long-necked” Karen is one of the Karen groups residing in Thailand’s Mae Hong Son province. The Term “long-necked” signifies the practice of adorning their women with brass rings around the neck. Bones in the neck are forced to grow longer because additional rings are added every few months which provide a repetitive and powerful force. One woman in Plam Piang Din Village wears 37 brass rings around her neck and she’s an old lady. Click here for pictures!FACT #3: In USA sports, professional baseball pitchers throwing arm is usually 1 to 2 inches longer than his other arm. (it is due to the vigorous exercise that the “throwing” arm exerts a more powerful force on the bone thus results in the remodeling of the arm). Click here for pictures!FACT #4: In professional Jai Alai almost every player’s right arm is about 1 to 2 inches longer than his left arm (this is considered as of a direct result of repetitive exercise motions). Click here for pic 1, pic 2, pic 3 FACT #5: Bone is a LIVING TISSUE (ask any medical student) and adapt in response to exercise and constantly adjust to the demands placed upon it. Bone is constantly being formed and resorbed. Bone growth occurs when calcified matrix is formed faster than it is resorbed. Diameter growth occurs when matrix deposition occurs on the outer surface of the bone. Linear growth in long bones occurs at epiphyseal plates. These plates are between the epiphyses and diaphysis of the bone. Columns of chondrocytes on the epiphyseal side divide continuously causing this growth (Silverthorn, 2001). As the collagen layer thickens, older collagen calcifies and older chondrocytes deteriorate. Osteoblasts lay down a bone matrix on top of a cartilage base. The shaft lengthens as new bone is added at the ends. As long as the epiphyseal plate is active, long bone growth continues (Silverthorn, 2001). Eventually, when the level of sex steroid hormones ceases to increase, the epiphyseal plate is inactivated. This causes long bone growth to stop (Silverthorn, 2001). And this may be the case that many people believe that growing taller after puberty is impossible. Source:www.bae.nesu.edu FACT #6: Bone will constantly remodel throughout life (ask any doctor). It is necessary to tell the bone where the areas of stress are going to be so that it can remodel and strengthen in preparation for the event. Bone cells, in particular osteocytes, are extremely sensitive to mechanical stress, a quality that is probably linked to the process of mechanical adaptation. “Throughout life, bone is constantly renewed through a process called remodeling. This process consists of two stages: resorption and formation. During resorption, old bone tissue is broken down and removed by special cells called osteoclasts. Once this has been done, bone formation begins and new bone tissue is laid down to replace the old. This task is performed by special cells called osteoblasts. Osteoblasts produce collagen, enzymes, and other proteins that make up the organic portion of the bone matrix.” FACT #7: Vigorous exercise and healthful diet with adequate calcium, protein, and vitamin D are essential in achieving sufficient bone mass during the bone adaptation process. FACT #8: Just like muscle, bones respond to certain kinds of training by hypertrophying. Source: http://www.apsu.edu/glassr/10 FACT #9: Bones are richly supplied with blood from periosteal vessels. Bone growth requires adequate amounts of nutrients, protein, calcium, vitamin D, etc. FACT #10: By putting enormous stress on bones, cartilage inside bones may become bones. FACT #11: The actual amount of growth in a bone depends upon the NEED for it (ask any researcher or doctor. As force is applied, the bone will remodel itself to better handle the force. In a basketball player, for example, the bones of the lower legs and feet strengthen to handle the impact of jumping. Although this will alter throughout life, the main effects will be seen during the period of growth, when remodeling is most evident. It is in this period that the actual length of a limb bone is being determined. The actual amount of growth in a bone depends upon the need for it. If u sit with weights on a high platform, the shin bone will need to reach deeper & deeper to the ground b/c the weights are pulling it down & that’s where the NEED is..for another instance, if u bike with raised saddle seat, the shin bone will NEED to reach more & more to reach the pedals.. FACT #12: Loading (stressing) a bone produces in it a small electrical field called piezo electric force, that needed to stimulate new bone formation (for anyone at any age who has sufficient calcium & vit. D). The vibrating platform appears to work by triggering bones to generate tiny electric fields. These tiny currents may turn on genes that affect bone remodeling and growth.That’s when a series of experiments showed that bone is piezoelectric, meaning that bending or deforming its crystal structure creates local electric currents. Physiologists quickly linked these currents to bone growth in studies that seemed to explain why exercise strengthens bones and immobilization weakens them.” Source: http://www.rense.com/politics5/mag.htm Bone remodeling appears to be governed by a feedback system in which the bone cells sense the state of strain in the bone matrix around them and either add or remove bone as needed to maintain the strain within normal limits. The process or processes by which the cells are able to sense the strain and the important aspects of the strain field are presently unknown. Bassett and Becker (4.2.1) reported that bone is piezoelectric, i.e. that it generates electric fields in response to mechanical stress; they advanced the hypothesis that the piezoelectric effect is the part of the feedback loop by which the cells sense the strain field. Source: http://silver.neep.wisc.edu/~lakes/BoneRemod.html Lastly, the discovery about piezo electric force inspired scientists to create different devices to encourage the body to make its own electric fields for building bones.” (Source: http://www.rense.com/politics5/mag.htm FACT #13: Bone adaptation was entirely defined by three constitutive laws: – The stress-strain law – The bone density evolution law – The bone anisotropy evolution law, etc. More facts and proof coming this Fall & Winter 2004

Ryan’s explanation

For anyone who is 21 years old or younger, the epiphyseal plate remains active and plays a major part in bone growth. Thus, many doctors and researchers believe that growing taller after puberty is not possible because the epiphyseal plate is closed.In contrast to the theory above, I believe that for those who are 21 years old or older, vigorous exercise and healthful diet with adequate calcium, protein, vitamin D, and supplements may replace the role of epiphyseal plate. Thus, bone adaptation is forced to occur because stress is exerted and supplements & vitamins continuously supply nutrients and food for bones.In other words, anyone who is 21 years old or younger, the epiphyseal plate remains active to give you that natural growth and your height is determined mostly by heredity or genetic factors. Whereas, those who are 21 years old or older do NOT depend on genetic factors but on stress factors & vitamins & supplements. Fact: The shape, strength, growth and form of a bone is determined not only by heredity but by the work it has to perform.

Proof – how bone remodeling works

Factors part of bone growth remodeling stage:

Piezo weak electrical currents (from kicking/biking with ankle weights)

Osteocytes

Osteoblasts

Stress factors (from sitting with ankle weights)

Calcium

Vitamin D

Centrum multi-vitamin (proteins)

Glucosamine

Chondroitin

Collagen fibers

Fibroblasts

Spongy bone

Bony callus

Compact bone

Shin bone (tibia)

Fibula

Enzymes

Bone matrix

Blood

Etc.

Below are some breathtaking pictures about bone remodeling.. be sure to read the caption carefully.

Did you know that your body gets taller in space? Because the spine is no longer compressed by the force of gravity, the vertebrae separate slightly from one another and the person’s body lengthens. This is NOT an example of bone remodeling because there is no force exerted on your body. However, it’s a great comparison between force and gravity. Lastly, your spine lengthens in space because gravity does not on act on it.Gravity does an amazing job in remodeling your bone. That explains why and how astronauts lose bone mass after being exposed to the weightlessness of space.

More pictures & proof coming this fall & winter 2004!

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Me: This is what Wikipedia states about the Wolff’s Law (source HERE)

Wolff’s law is a theory developed by the German anatomist and surgeon Julius Wolff (1836–1902) in the 19th century that states that bone in a healthy person or animal will adapt to the loads it is placed under.^[1] If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading. The internal architecture of the trabeculae undergoes adaptive changes, followed by secondary changes to the external cortical portion of the bone,^[2] perhaps becoming thicker as a result. The converse is true as well: if the loading on a bone decreases, the bone will become weaker due to turnover, it is less metabolically costly to maintain and there is no stimulus for continued remodeling that is required to maintain bone mass.^[3]

In relation to soft tissue, Davis’s Law explains how soft tissue remolds itself according to imposed demands.[edit]Associated laws

• Refinement of Wolff’s Law: Utah-Paradigm of Bone physiology (Mechanostat Theorem) by Harold Frost.

Examples

• The racquet-holding arm bones of tennis players become much stronger than those of the other arm. Their bodies have strengthened the bones in their racquet-holding arm since it is routinely placed under higher than normal stresses.
• Surfers who knee-paddle frequently will develop bone bumps, aka exostoses, on the tibial eminence and the dorsal part of the navicular tarsal bone from the pressure of the surfboard’s surface. These are often called “surf knots.”
• Astronauts who spend a long time in space will often return to Earth with weaker bones, since gravity has been absent and therefore has not exerted a force on their bodies.
• Weightlifters often display increases in bone density in response to their training.
• Martial artists who strike objects with increasing intensity (e.g. repeated elbow strikes), display increases in bone density in the striking area. This process is termedcortical remodeling.

From the website Teambone.Com….

After nearly 25 years of work in skeletal anatomy, adaptation, and orthopaedics, Julius Wolff published his seminal 1892 work on bone ‘transformation’ (known today as bone remodeling and modeling). Wolff’s work and his general view of how a limb bone’s morphology develops has evolved into a nebulous concept known as “Wolff’s law”, which is essentially the observation that bone changes its external shape and internal (cancellous) architecture in response to stresses acting on it. Although the rationale for the existence of Wolff’s law has been challenged on many fronts (e.g., Bertram and Swartz, 1991; Cowin, 1997; Currey, 1997; Cowin, 2001), many contemporary investigators still ascribe to the idea that there is a “Wolff’s law” that states that bone models and remodels in response to the mechanical stresses it experiences so as to produce a minimal-weight structure that is ‘adapted’ to its applied stresses.

For example, should a fracture of a weight-bearing long bone heal with an angulation, each step that the patient subsequently took would result in a bending stress with compression on the concave side at the angulation and tension on the convex side. Rather than progressively weaken the bone structure at this site, such repeated mechanical stress results in a modeling and remodeling, with new bone growth on the concave side and bone resorption on the convex side. If the patient is young enough, the bone will ultimately grow straight. In control-system terms, the applied mechanical stress causes a growth response that negates the applied stress — a closed-loop negative-feedback control system.

Many authors have made relevant observations regarding the phenomena of bone modeling and remodeling. An orthopaedic surgeon named Harold Frost made the following salient points:

1. Remodelling is triggered not by principal stress but by “flexure”.
2. Repetitive dynamic loads on bone trigger remodelling; static loads do not.
3. Dynamic flexure causes all affected bone surfaces to drift towards the concavity which arises during the act of dynamic flexure.

To define some basic terms of bone growth, we have compiled the following list of characteristics in the formation (osteogenesis), modeling and remodeling of bone.

Osteogenesis

• Bone formed on soft tissue
• Occurs during embryonic development, early stages of growth, and during healing
• Two major subclassifications: intramembranous ossification and endochondral ossification
• Intramembranous: bone formed on soft fibrous tissue
• Endochondral: bone formed on cartilage
• Osteoblasts derived from mesenchymal cells act indepdendent of osteoclasts
• Potential to create large amounts of bone

Modeling

• Bone formed on existing bone tissue
• Occurs during growth, and during healing
• Osteoblasts and osteoclasts act independently at different sites
• Potential to create or resorb large amounts of bone

Remodeling

• Bone both resorbed and formed at the same site
• Occurs from growth through death.
• The only normal physiologic mechanism for altering bone structure in adult skeleton
• At best leads to maintenance of bone; however as we age leads to net loss of bone (osteoporosis)

Me: The topic and controversy of Wolff’s Law is actually something I believe is critical to understand for any one who truly believes that height increase is possible using any form of non-surgical method of exercise or loading. This subject will be continure further in another article for another day.

Here’s a paper with a more detailed explanation of Wolff’s Law:

The Aging of Wolff’s “Law”:Ontogeny and Responses to Mechanical Loading in Cortical Bone

“The premise that bones grow and re-model throughout life to adapt to their mechanical enironment is often called Wolff’s law. Wolff’s law, however, is not always true, and in fact comprises a variety of differ-ent processes that are best considered separately. Here we review the molecular and physiological mechanisms by which bone senses, transduces, and responds to mechaical loads, and the effects of aging processes on the relationship (if any) between cortical bone form and mechanical function. Experimental and comparative evidence suggests that cortical bone is primarily responsive tos train prior to sexual maturity, both in terms of the rate of new bone growth (modeling) as well as rates of turnover(Haversian remodeling). Rates of modeling and Haversian remodeling, however, vary greatly at different skeletal sites. In addition, there is no simple relationship between the orientation of loads in long bone diaphyses and their cross-sectional geometry. In combination, these data caution against assuming without testing adaptationist views about form-function relationships in order to infer adult activity patterns from skeletal features such as cross-sectional geometry, cortical bones density, and musculoskeletal stress markers. Efforts to infer function from shape in the human skeleton should be based on biomechanical and developmental models that are experimentally tested and validated. ”

“ratios of articular width relative to bone length were closely correlated among long bones throughout the skeleton (with the exception of the clavicle) and that these”

““Wolff’s law” today (see be-low), actually incorporates three concepts : bone is deposited and resorbed to achieve an optimum balance between strength and weight, trabeculae in cancellous bone tend to line up with the directions of principal stresses that they experience, and both phenomena occur through self-regulating mechanisms that respond to mechanical forces acting upon bone tissues”<-it would be interesting to see how much atypical loading could change bone.  For example, bone is highly subject to axial loading rather than lateral loading.

“Bone is essentially a two-phase substance (like fiberglass or reinforced concrete):about 35% of a bone’s weight is organic, comprised mostly of collagen fibers, along with a small percentage of noncollagenous proteins; the other 65% of bone is largely a calcium-phosphate mineral known as hydroxyapatite, Ca10(PO4)6(OH)2, that contains traces of various impurities such as citrate, fluoride, and magnesium. Osteoblasts synthesize bone in a two-step process. First, they secrete an initial collagen matrix (osteoid), typically in an organized lattice that forms the basic histological framework of the tissue. Osteoblasts then mineralize the collagen by precipitating crystallites in the form of needles, rods, and plates within and between the collagen fibers”

“Young’s modulus is a critical parameter that in-fluences bone function because of the deleterious effects of strain on bone structure via creep and fatigue, both of which contribute to fracture damage.  Cyclic stresses produce fatigue and promote creep, but creep can also happen in response to continuously applied loads, and tensile and compressive loads produce somewhat different effects”

” strains initiate microcracks, whose size and rate of accumulation are primarily determined by the tis-sue’s structure as well as by variations in applied stress magnitudes, strain rate, and number of cycles. Second, these cracks grow and propagate largely as a result of the structural characteristics of the tissue. The greatest potential danger of micro-damage accumulation is that cracks can begin to coalesce at some threshold, rapidly weakening the tissue and leading to mechanical failure.”

“mechanotransduction, the process by which cells sense mechanical stimuli in their external environment and then translate the informationinto a signal that can potentially elicit some response either within the cell or in another cell.  [possible hyptothesis]  is that specialized osteoblast cells called osteocytes act as strain receptors and transducers ”

“Osteocyte canaliculi are filled with fluid that is displaced every time a bone deforms, and the cells appear to be quite sensitive to pressure changes from these flows, inducing prostaglandin and nitric oxide (NO) production, and triggering communication at gap junctions”

“strain-induced fluid flow within bone matrix generates small changes inelectrical charge”