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 July 2002 questions are posted below. ( View Archive )

Test yourself, July, 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 six and seven 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.

126. Figure 6.1. In this casual forward bend, unless one is given specific instructions for activating the hip flexors, they will be relatively passive.

Figure 6.3. The 150 degrees of hip flexion in this figure is accomplished by the upper extremities, not the hip flexors, which themselves remain passive.

Figure 6.4. The 80 degrees of hip flexion with the right knee straight is accomplished in part by tugging on the thigh with the upper extremities, but it is also natural to support the stretch with both the right psoas muscle and the right iliacus. This is easily overlooked, however, because so many other things are going on in the posture, such as hamstring stretch, efforts to keep the knee straight with the right quadriceps femoris muscle, and by the contribution of the rectus femoris in supporting hip flexion synergistically.

Figures 6.5-6. Because the model is advised not to use the upper extremities to pull into the posture, the psoas and iliacus muscles are doing most of the work (isotonic, then isometric) in pulling forward and holding the position. And in all such bends done by beginners or by those who are relatively inflexible, the action of the iliacus will be more important than the psoas. And since the iliacus pulls forward selectively on the ilia, sacroiliac counternutation is emphasized over nutation.

Figure 6.10. For advanced students who have the awareness to thrust their lumbar region forward maximally, this is a vigorous exercise for the psoas muscles. Acting from their working origins on the femurs they first pull the lumbar lordosis forward (and in so doing create a selective effect on the promontory of the sacrum), and then they act isometrically to hold the position. The position also creates maximum nutation, acting as it does to pull the promontory of the sacrum forward and tending to leave the ilia behind.

Figure 6.11. Continuing to bend forward from the hips, the emphasis now begins to shift from the psoas muscles to the iliacus muscles, although both remain active in pulling forward, and the sacroiliac joints accordingly ease into a more neutral position between nutation and counternutation.

Figure 6.12. The completed posterior stretch features easing yet further into counternutation, relaxation of the psoas muscles, and for those who are able to focus their attention on pulling forward on the ilia, full tension in the iliacus muscles.

Figure 6.13. To come into this rounded-back forward bend, the model shortens both the psoas and iliacus muscles concentrically, with perhaps a slight emphasis on the iliacus, which in turn emphasizes counternutation.

Figure 6.14. As the model leans slowly to the rear, the hip flexors (again with emphasis on the iliacus) lengthen eccentrically to restrain the movement.

Figure 6.15. The psoas and iliacus muscles should all be active in pulling forward.

Figure 6.16. The hip flexors are mildly stretched and resist lifting of the body to a straight position.

Figure 6.17. In this intermediate-level down-facing dog, the psoas muscles are actively pulling forward on the lumbar region of the spine in order to keep the posture looking sharp. Depending on sacroiliac flexibility, nutation will be emphasized.

Figures 6.19-20. In all of these poses the hip flexors will be passive, as the impetus for coming into them is from the upper extremities.

Figure 6.21. One should use the hip flexors to initiate coming into these poses, but the emphasis quickly changes to using the upper extremities to aid completion of the poses.

Figures 6.25a and c. The preliminary pigeon mildly stretches the hip flexors for the rear thigh, and the advanced pigeon stretches them even more.

Figures 6.26a-b. The psoas muscle for the front thigh should be especially active for coming into this intermediate position for the angle pose. Nutation on the right side is emphasized. Then as the pose is completed, the iliacus muscle for the front thigh pulls forward deeply on the right ilium.

127. Figures 7.17-18. In all of these twists and bends in the cases of advanced students the forward bends to one side makes use of the hip flexors to pull down to that side, and the forward bends straight to the front makes use of the hip flexors on both sides (with gravity aiding the effort). The psoas muscles and sacroiliac nutation are emphasized over the iliacus as one starts to come into the forward bend with a sharp lumbar lordosis, and as the bend is continued, the iliacus contributions become more obvious, nutation is eased, and the sacroiliac joint or joints come into a more neutral position. For beginning students, the hip flexors are not nearly as important for coming into the posture as gravity. In the backbends the hip flexors resist the pull to the rear, on the side opposite to the backbend in the case of bending to one side, and on both side in the case of bending symmetrically to the rear.

Figure 7.19. The right hip flexors are passive in the standing warrior II, and the left hip flexors are mildly stretched and eccentrically lengthened as the model drops into the pose.

Figure 7.20. The right hip flexors are still passive in the standing warrior I, but the left hip flexors are stretched and eccentrically lengthened more prominently due to the increased degree of left hip hyperextension in comparison with the standing warrior II.

Figures 7.24-33. All the sitting spinal twists make some use of the hip flexors, especially in the initial stages of coming into the poses. In all of the starting sitting positions one should try to sit up straight and then maintain the upright postures as much as possible while proceeding into the various postures, and this means the psoas muscle will pull forward on the lumbar lordosis and the iliacus muscles will create a lifting and pulling-forward effect on the ilia that will also aid sitting up straight.