Adaptation of muscle to eccentric exercise and its clinical applications 194272 [ 2002 - 2004 ]

Research Grant

Researchers: Prof David Morgan (Principal investigator) ,  Dr Paul Percival ,  Prof Uwe Proske

Brief description Work in this laboratory has concentrated on Delayed Onset Muscle Soreness (DOMS), the soreness felt for several days after unaccustomed exercise. This is particularly so when the exercise involves stretching of active muscle, called eccentric exercise, at longer muscle lengths. DOMS is due to microscopic muscle damage. A rapid training effect, leading to reduced soreness from a subsequent bout of similar exercise, has been identified by us as due to a specific structural adaptation. This results in the optimum length for tension generation moving to longer muscle length so that the muscle is less likely to be damaged during subsequent stretches. Hypothesizing that gross muscle tears arise from the microscopic damage, we have begun investigating whether eccentric exercise training can prevent hamstring muscle injuries. We have shown that eccentric exercise shifts the optimum length for contraction in human hamstring muscles. We are now examining athletes with past injuries, known to be likely to re-injure. Other experiments are designed to show that sports that cause injury do indeed include eccentric exercise of the hamstring muscles. We are also investigating the effectiveness of eccentric exercise in treating apparently normal children who compulsively walk on their toes. We have built monitoring equipment and are monitoring both conventional and exercise based treatments designed to shift muscle optimum length to longer lengths to allow the children to place their heels on the ground. Finally, most muscles contain different fibre types, distinguished mainly by their speed of contraction. It has been suggested that they are not all uniformly susceptible to damage from eccentric exercise, a result not predicted by our theory. However, we hypothesize that secondary factors, particularly the length for generating optimum tension, may be responsible for these differences. We plan to test this idea by measuring properties of different types of motor units.

Funding Amount $AUD 196,410.00

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant