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Limb lengthening surgery: Limb
lengthening surgery is an excellent example which proves that bones remodel,
re-build, grow, thicken, heal, or lengthen due to a stretching force (either
by limb lengthening device or by heavy ankle weights).
With limb lengthening surgery, a large fracture is created when surgeons cut
the shinbone in half. Gradually, the doctors use a leg lengthening device to
stretch out the bones as new bone growth is formed to fill the gap.
On other hand, a large fracture can never be created with intense sprinting
or running. However, microfractures or extremely tiny fractures (in the
shinbone) may be created following intense sprinting or running. Instead of
using a leg lengthening device, shinbone experimenters may apply ankle
weights to stretch out the shinbone.
Bone is a LIVING TISSUE: Ask any scientist or doctor and they
will agree. medical student and adapt in response to exercise and constantly
adjust to the demands placed upon it.
Ask
any doctor and they will tell you:
It takes a healthy bone every 3 years to remodel; however, it only
takes a fractured bone a week to heal remodel. As you can see, by creating
microfractures with intense sprinting/running, you will have a very HIGH
chance of lengthening your lower legs.
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
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.”
Vigorous exercise and healthful diet with adequate calcium, protein, and
vitamin D are essential in achieving sufficient bone mass during the bone
adaptation process. Just like muscle, bones respond to certain kinds of
training by hypertrophying.
Source: http://www.apsu.edu/glassr/10
Bones are richly supplied with blood from periosteal vessels. Bone growth requires adequate amounts
of nutrients, protein, calcium, vitamin D, etc. By putting enormous stress on
bones, some cartilage inside bones may become bones.
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..
Loading (stressing) a bone produces in it a small electrical field called
piezo electric force, that needed to stimulate new bone formation.
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
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