Biomechanics of Bones and Ligaments in Primates: The Effects of Strain Rate, Exercise, and Reconditioning on Ultimate Properties.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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Experiments were conducted to determine the effects of strain rate, exercise, and reconditioning on bones and ligaments in Rhesus monkeys. In the strain rate tests, the anterior cruciate knee ligament was tested to failure in tension. The maximum load of this ligament increased 24 when the strain rate was changed from 0.2 inchmin to 20.0 inchmin. In the exercise tests, Thesus monkeys were induced to exercise their right leg while the rest of their body was kept immobilized in a plaster cast. At the end of eight weeks of exercise the monkeys were sacrificed. The anterior cruciate ligaments were tested to failure in tension, while the tibae, femora, and humeri were tested to failure in torsion. Eight weeks of exercise was not sufficient to compensate for the weakening effects of partial immobilization of the body. In the reconditioning tests, Rhesus monkeys were first totally immobilized in plaster body casts for a period of eight weeks. At the end of this period, the monkeys were removed from the plaster casts and transferred to large cages for recuperation. The monkeys remained in the large cages for 16 or 24 weeks. At the end of these periods the monkeys were sacrificed. After 24 weeks of reconditioning, the knee ligament had not completely recovered from the weakening effects of immobilization, while the femur and humerus had recovered their normal strength. Author Modified Abstract
- Stress Physiology