1. Have a partner lie supine on a table with hands on shoulders and hips and kne
ID: 3480631 • Letter: 1
Question
1. Have a partner lie supine on a table with hands on shoulders and hips and knees extended. Palpate the small of the back to detect whether it is contacting the table or whether it is arched upwardly. Ask the partner to press the small of the back to the table (posterior pelvic tilt) and palpate the abdominals. Which muscles are acting as agonists and which as antagonist, as this is done? Assume your partner is unable to press the back to the table. Which muscles should be strengthened and which should be stretched? 2. Having completed Experience 1 above, have your partner bend the knees so the feet can be placed flat on the table. Palpate the small of the back and notice that it is easily touching the table. Which muscles have been slackened by placing the legs in this new position? 3. Now ask your partner to straighten the legs and raise them briefly a few inches off the table. What happens to the small of the back? Why? 4. Ask your partner to lie supine and have your partner bend the knees so the feet can be placed flat on the table. Ask your partner to perform diagonal abdominal curls touching the right elbow to the left knee. What muscles are working on the way up? Are the contractions concentric or eccentric? What muscles are working on the way down? Are the contractions concentric or eccentric? 5. Now, ask your partner to stand and slowly forward flex the trunk. What are the agonist muscles in this experiment? Is the contraction concentric or eccentric? Explain
Explanation / Answer
1. When a person is in supine position with hands on shoulders and hips and knees extended and posterior pelvic tilt is done, the muscles which act as agonist is Rectus Abdominis and antagonist are Erector Spinae (Iliocostalis, Longissimus, Spinalis), Latissimus Dorsi.
2.When the person bends the knees the erector spinae muscles is slackened.
3.When a person is asked to raise their legs off the ground, the gluteus maximus muscles is contracted and it tries to fix the posterior pelvic tilt.
4. when abdominal diagonal curls are done the muscles involved are all abdominal muscles like rectus abdominis, transverse abdominis, internal and external oblique muscles. During this phenomenon there will be eccentric contraction to overcome the resistance and to strenghten the muscles.
5.when the person is standing and flexing the trunk, the agonist muscle is rectus abdominis and antagonist is erecor spinae. It is concentric contraction seen during this movement. Since when we bend the rectus abdominis muscle contract and shortens, it is said to be concentric contraction.
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