I have a student who I had do the knee flexion-extension exercise from your book and when she flexed the knee she felt a sharp, knife-like pain deep under the groin area. I asked her exactly where and she showed an area between the pelvis and femur to the front. She is an aerobics instructor and the other day when she got out of bed and turned to walk she felt this deep pain again and ended up this time having the pain last and was limping when I saw her. The next day I saw her again and she wasn’t limping. She said she had gently stretched the area and could walk without pain, but that she couldn’t put any weight/pressure on that leg/foot or the pain returned. Any suggestions as to what may be causing this problem. She did say in passing that the pain has first been noticed either during or right after delivery of her first child.
Sounds like one of two possibilities. The gentler explanation is that she needs to turn her thigh outward from the hip joint as she goes into flexion. This is commonly uncomfortable as the motion moves around the psoas and inguinal ligament. If this is the case strengthening the psoas and other external hip rotators may provide relief. This is done by leg lifting with external rotation while lying supine, one leg at a time. The more challenging scenario is that she may have an inguinal hernia that can also make walking difficult. If the first motion alleviates the problem not to worry. If it doesn?t, I recommend she see a physical therapist or experienced bodyworker.