Body and Breath

Each month a new series of 10 questions will be posted on the Test Yourself page. The following month the questions will then be posted here along with the answers and explanations.

Answers to the August 2002 questions are posted below. ( View Archive )

Test yourself, August, 2002, with answers

You are teaching practical aspects of anatomy to a group of experienced hatha yoga teachers. The assignment: Using the postures discussed in chapters eight through ten of Anatomy of Hatha Yoga as a frame of reference, find examples (where applicable) of both stretching and exercise for the hip flexors (the psoas and iliacus muscles). Distinguish between active stretch and passive stretch in the instances of stretching, and distinguish between isotonic and isometric situations in the instances of exercise. Also distinguish between the psoas muscles and the iliacus muscles where applicable, and make comments on their effects on sacroiliac nutation and counternutation.

128. Figure 8.23. The stick pose emphasizes isometric tension in the psoas muscles, and, with that tension pulling forward selectively on the lumbar region and promontory of the sacrum, nutation is favored over counternutation.

Figure 8.24. The two-handed cobra places emphasis on hip flexibility, but after getting into the posture, it requires little or no effort on the part of the hip flexors. The position is also neutral with respect to sacroiliac movements, although the round back and fully flexed thighs suggests the tendency will be on counternutation.

Figure 8.25. There will be extreme isometric activity in the iliacus muscles in the celibate's pose. The psoas muscles will be active as well, but it will be the iliacus muscles that bear the brunt of keeping the thighs flexed 90 degrees at the hips. The lower back, which is slightly rounded to the rear, suggests the sacroiliac joints will be in a state of counternutation, which is resisted, however, by the psoas muscles. Beyond keeping the hips flexed 90 degrees with the hip flexors, the main actors in this pose are the abdominal muscles, the deep back muscles, and the respiratory and pelvic diaphragms, all (with the exception of the respiratory diaphragm) acting isometrically.

Figure 8.26. This expert's down-facing dog makes special use of extreme isometric tension in the psoas muscles, which keeps the lumbar region perfectly straight. They will also create (somewhat unsuccessfully) an emphasis on sacroiliac nutation.

Figure 8.27. The easy down-facing dog features passive hip flexors and a neutral position between nutation and counternutation. Trying to straighten the back and flex the thighs more than is shown here will result in more stretch and tension in the psoas muscles.

Figures 8.28-30. In all of these postures, the psoas muscles will be actively working to emphasize nutation and to maintain the angle between the thighs and the lower back. Concentric activity in the psoas muscles (lifting up against the force of gravity) will be the rule as the hips are lifted, and eccentric lengthening of the psoas muscles (resisting gravity) will be the rule as the hips drop and the nose comes forward.

Figure 8.31. The beginning position for the scorpion is similar to the dolphin with respect to sacroiliac movements and activity in the psoas muscles. In the final position, all the hip flexors are stretched and lengthened eccentrically, resisting the tendency for gravity to drop the lower extremities further to the rear.

Figure 8.32. In the home position (b), the psoas muscles are stretched maximally and the sacroiliac joints are in a state of full nutation. Moving toward (a), on the other hand, flattens the lumbar region and eases the sacroiliac joints into counternutation. To initiate a movement toward (c) from (b), the hip flexors nudge the knees forward and then gravity flexes them toward their final position.

129. Figure 9.2. The sacroiliac joints move into a relaxed position tending, however, toward counternutation. The hip flexors are relaxed.

Figures 9.20-22. These three postures all stretch the hip flexors, especially the psoas muscles.

Figure 9.23. This extreme posture pulls the sacroiliac joints into full counternutation in order to permit the thighs to pull down alongside the torso even further than would be expected in the posterior stretch.

130. Figures 10.7-9, and 10.11-16. These sitting poses all share common characteristics as far as activity in the hip flexors and sacroiliac movements are concerned. For advanced practitioners, the psoas muscles are especially active, pulling the sacroiliac joints toward nutation and sharpening hip flexion toward 90 degrees. Experienced and knowledgeable students can also feel the difference between the deep pulling forward of the ilium (creating an anterior pelvic tilt) by the iliacus muscles on one hand, and the characteristic feel of pulling the lumbar lordosis forward with the psoas muscles. In all cases, the postures will be stable and thus the muscular activity will be isometric in nature. Beginners sitting flat on the floor will have a very different experience. Since they are unlikely to have 90 degrees of hip flexibility, their lumbar regions will be rounded posteriorly, their pelves will be tilted posteriorly, their sacroiliac joints will either be locked or tending toward counternutation, and their psoas muscles will not be effective in keeping their backs flat, much less arched forward. Sitting on a cushion or bench will remedy this situation to some extent in that they may be able to preserve their lumbar arches and pull the promontory of the sacrum forward to create some nutation.

Figure 10.10. The easy posture is a special case. Moderate instability is the rule here unless the student has had long practice, because whenever the hip flexors act to lift the posture and pull the lumbar region forward, they also are likely to lift the knees (that is, flex the thighs), which, after all, is what hip flexors do. A beginner sitting flat on the floor is constantly readjusting the posture. Sitting up on a support not only eases the problem of hip flexibility, it stabilizes the knees and thus makes the posture as a whole more stable.