The Henneman size principle of therapeutic exercise says motor units are recruited in order of
(A) increasing size, decreasing contraction strength, and diminishing fatigue
(B) increasing size, increasing contraction strength, and diminishing fatigue
(C) increasing size, increasing contraction strength, and escalating fatigue
(D) decreasing size, increasing contraction strength, and diminishing fatigue
(C) Smaller, less powerful, fatigue resistant motor units, which contain slow-twitch muscle fibers, have the lowest firing threshold and are recruited first. Demands for larger forces are met by the recruitment of increasingly larger, more powerful, fatigable motor units. The largest motor units that contain the fast-twitch B fibers have the highest threshold and are recruited last.
What is an example of an open kinetic chain exercise?
(B) Open kinetic chain exercises are typically performed where the foot/leg or hand/arm is free to move, and non-weight bearing, with the movement occurring at the peripheral joint. Examples of these exercises would be knee extensions, straight leg raises, and biceps curl. In closed kinetic chain (CKC) exercise, the distal part of the limb-upper or lower, is fixed to the ground or to the wall or plate. Examples include leg press, push up, and running exercises. In bench press, the foot is on the floor so this too is a CKC exercise. CKC exercises are felt to be more "functional", since these exercises may mimic what patients do throughout the day or in an employment setting and thus are often favored. However, a mix of both types of exercises typically recommended.
Which type of therapy has been found to reduce the risk of falls in the elderly?
Tai chi is an internal Chinese martial art often practiced with the aim of promoting health and longevity. Training consists of slow motion routines that groups of people practice together every morning in parks around the world, particularly in China. Many medical studies support its effectiveness as an alternative exercise and ...