as elastin & glycoproteins. Adjacent collagen fibres are held together by proteoglycans and new collagen is secreted by fibroblasts. Fibroblasts arrange collagen fibres into bundles which are called fascicles. Blood supply of a ligament is very , hence the white colour of a ligament. Ligaments are not as strong as tendons and do not possess as much elastic properties as well.
The Biophysical Properties of Tendons & Ligaments Tendons and ligaments have three distinct phases to their mechanical functionality.
The first phase is the
phase, which is used to describe the normal, physiological
function of tendons/ ligaments. The elastic phase exists from - percent extension of the normal resting wave pattern of collagen fibres. During this phase the tendon/ ligament is compliant. It extends readily and returns to the normal length and crimp pattern easily once the load is removed. percent extension of the normal resting wave pattern of collagen fibres. During this phase there are structural changes in the wave pattern and the organization of the collagen fibres in a tendon/ ligament. As the extension increases, the collagen fibres lose their crimped structure, which causes an increase in the distance between fibres. This results in a breakdown of the connection between adjacent collagen fibres and has the effect of weakening the tendon/ligament and decreasing the elasticity of the tendon/ligament. At the upper range of this phase the wave pattern of collagen may be completely lost. The second phase, the phase, occurs between -
The third phase is considered tendon/ligament
. This occurs where there is
- percent extension of collagen fibres. During this phase the linear arrangement of collagen molecules is disrupted causing discontinuity in the tendon/ligament, complete loss of elasticity and unlimited lengthening of the musculotendinous fibres. describes a gradual extension of collagen fibres within a tendon/ligament, and the associated decrease in the elasticity and compliance of the tendon/ligament. Creep occurs when there is extension of the collagen fibres slightly beyond their physiological limit, or where slight hyperextension is held for a prolonged period. Creep has the overall effect of lengthening the musculotendinous unit, decreasing the resilience of the tendon/ligament, decreasing the elasticity of the tendon/ligament and decreasing tension on the tendon/ligament. This makes the tendon/ligament more vulnerable to strain/sprain and requires that a greater muscular contraction is needed to achieve the same degree of change in the joint angulation. The structural and functional changes seen with creep are .
Common injuries to tendons & ligaments include the following pathological conditions.
Tendinopathy – any condition involving a tendon
Tendonitis - inflammation or irritation of a tendon which may result in the tearing of fibres, leading to a tendon strain
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