The muscle is stretched by outside forces or antagonist muscles frequently occur in normal conditions like walking down the stairs. When these contractions are repeated by someone out of shape, they make muscles weak and a characteristic muscle pain and tenderness; which become known a day or so after the workout. This type of damage to the muscle is linked with inflammation, hypercontracture of some fibers and protein loss from the damaged fibers. This type of pain and weakness can be the cause of some muscle symptoms in muscle diseases.
**Fun Fact**-Skeletal muscle fibers from rats with heart failure are more liable to mechanical damage, which shows that these muscles are more easily damaged during eccentric contractions.
Eccentric muscle damage includes characteristic changes to the sarcomeres with over- or under-stretched sarcomeres and wavy Z-lines. These are changes which have been explained by instability of sarcomeres in these situations. Evidence also shows that increased resting may act as a stimulus for inflammation and reduce Ca^2+ transients during these contractions, which add to the decreased force. A recent study has given researchers new information on possible early membrane damage after eccentric contractions. Vacuoles which were attached to the t-tubules were examined after contractions. Their figure could be held back by blocking the Na^+-K^+ pump. It was suggested that overstretched sarcomeres led to membrane tears, which allows the influx of ions like Ca^2+ and Na^+. The T-tubular-associated vacuoles are also a common thing in the damage of muscles and disease. Vacuoles and linked damage to t-tubules could hurt many cellular processes, such as, the action of exchangers and pumps in t-tubules, which can further hurt cellular dysfunction following the eccentric damage.
Overall, eccentric muscle damage can further damage other bodily processes if not taken care of in time. They are trying to find more and more things to cure this type of muscle damage.
Research Article:
http://www.medscape.com/viewarticle/444388_5
No comments:
Post a Comment