11. analyze the following activities for the total body. state the prime mover(s) for each joint motion, the type of muscle contraction, and the essential stabilizing muscles: a. supine: perform a sit-up and return to the starting position. b. prone: raise head and shoulders and extend the trunk. c. prone: perform a push-up. d. standing: perform a chin-up. e. standing: bend forward and touch the floor and return. f. standing: sit down in a chair and return. g. ascending stairs for lead leg and for following leg. descending stairs.

A) Prime Mover: abdominal rectus abdominis. Also important iliac psoas.

The type of contraction is concentric isotonic contraction at first, and when returning to the initial position, eccentric isotonic contraction.

The essential stabilizing muscles are the latissimus dorsal, the serratus posterior and the thoracolumbar fascia

Explanation:

B) Prime Mover: erector spine muscles. Head and crevicis longissimus, spinal cervical, thoracic longissimus, spinal thoracic, illiocostalis thoracic, illiocostalis lumborum and finally common tendon.

The type of contraction is isotonic contraction because muscles fibers change size to extend the trunk and head. In this case the contraction is eccentric because the fibers of the erector muscles return to their position.

The essential stabilizing muscles are all of those that are part of the anterior wall of the abdomen.

C) Prime Mover: pectoral major, deltoids and triceps.

The type of contraction is isotonic concentric and eccentric contraction. The muscles fibers shorten when we push-up from the floor and lengthen when we go down to the floor.

The essential stabilizing muscles involve are the grand dorsal, grand rond, infra-epineux, petit rond and trapeziums.

D) Prime Mover: the prime muscles involved are trees major and the grand dorsal. Also biceps brachial.

The type of contraction is isotonic concentric contraction and eccentric contraction.

The essential antagonist or stabilizing muscles are triceps and all abdominal muscles likes rectus and obliques.

E) Prime Mover: Rectus abdominalis.

The type of contraction is isotonic concentric contraction.

The main stabilizing muscles are the spinal extensor muscles.

F) Prime Mover: quadriceps, hamstrings and glutes. Also is used iliac psoas and abdominals.

The type of contraction is isotonic eccentric contraction.

The main stabilizing muscles are back extensors muscles like thoracolumbar fascia, erector spinae, rhomboids and grand dorsal.

G) Prime Mover ascending stairs: quadriceps and glutes. Also tibial anterior participates by dorso flexing the feet.

The type of contraction is concentric isotonic contraction.

The essential stabilizing muscles are biceps femoral, semimembranosus muscle, and also lower abdominals.

Prime mover descending stairs: also quadriceps, gastrocnemius, soleus muscle.

The type of contraction is isotonic and also isometric contraction when the quadriceps are holding on our weight.

In order to understand completely this exercise you will have to comprehend body biomechanics and why we have agonists muscles and antagonists muscles.