KINESIOL 4SS3 Lecture Notes - Lecture 7: Vastus Lateralis Muscle, Myocyte, Neuromuscular Junction
19 Sep 2016
School
Department
Course
Professor
Document Summary
Aging associated with a significant decrease in muscle mass (sarcopenia) which contributes to the decline in muscle strength. Many factors are thought to contribute to sarcopenia. Factors: age, height, weight, genetics, poor health, disuse, smoking, sedentary lifestyle, hormones, female gender. Age associated decline in muscle mass accompanied by a decrease in muscle strength. After age 65, strength declines by ~15% per decade. During growing years, strength increases: adult life can maintain strength better than others, range between people becomes progressively more. Some fair better with age than others (lifestyle, etc. ) Better maintenance: muscles used in daily activity, eccentric muscle strength. Little decline from 100% no decline state. Stronger because resistance to stretch that creates additive force. More additive force with stretching muscles: slow velocity contractions. Greater decline: muscles used infrequently, concentric or isometric strength. Ex, plantar flexors, dorsi flexors, knee extensors: high velocity contractions. The higher the velocity demands, the lower the relative tension that the aged muscle can generate.
