from eccentric exercise, primarily because of the reduced strain on muscle-tendon groupings as compared to traditional concentric exercise. Stretching of the muscles and eccentric training provides protection from injury or re-injury. Eccentric training has proven to be an excellent post rehabilitation intervention for lower-body injuries. Subjects report less weariness from eccentric training than from concentric training. Total body eccentric training can raise resting metabolic rate by about 9 percent, with the greatest magnitude in the first two hours. While energy costs remain low, the degree of force is very high. This leads to muscles that respond with significant increases in muscle strength, size and power. Eccentric exercise Eccentric exercise or resistance training is currently being used as a form of rehabilitation for sport injuries, but also as an alternative form of exercise for the elderly, those affected by neurological disorders, COPD, cardiopulmonary disorders, and cancer. Muscle loss is a big problem faced by the people afflicted with the above disorders and many cannot participate in rigorous exercise protocols. Eccentric muscle contractions produce high forces with low-energy cost. According to Hortobágyi due to these properties eccentric exercise has the greatest potential for muscle strengthening. To strengthen muscle the external force must exceed the muscle while it lengthens. The definition of eccentric contraction is almost the exact definition of muscle strengthening. Perceived muscle damage: There is a stipulation regarding eccentric contractions in that they actually cause muscle damage and injury. Eccentric contraction may result in delayed onset muscle soreness however; the contraction itself does not cause muscle damage or injury. Proof of muscle strengthening without damage: One recurring problem in ACL rehabilitation is improving muscle strength of the quadriceps without re-injury. Early, high-force eccentric training can be used to increase muscle strength and volume without damage to the ACL graft, surrounding soft-tissue, and the articular cartilage. In an experiment performed on rat muscles after twenty sessions of treadmill low intensity eccentric training the wet weight of the muscles and the fiber cross-section were significantly larger than the control and level groups. These results led to the conclusion that low intensity eccentric contractions have the ability to "produce enough mechanical stress to induce muscle hypertrophy without over-stressing which could produce muscle fiber damage. Other articles have found that muscle damage is not required to reach hypertrophy. Greater mechanical stress brought on by eccentric contractions is what leads to hypertrophy in individuals undergoing eccentric