Last week I mentioned several possible causes of injury from running due to poor mechanics. I mentioned that an anterior pelvic tilt is a possible cause of injury for runners and this week will look at how that can create an injury. I have had two occasions where an anterior pelvic tilt has caused problems. It is important to understand that the pelvic area is the junction between the legs and the trunk of the body. If the pelvic girdle is out of alignment, the working between the legs and the low back, abdominal muscles and upper body is compromised.
One occasion came when I started to increase my mileage for a marathon. I did not have any problems with the shorter distances for 5K and 10K races. When I moved the long-run mileage between 18 and 22 miles the problems began to appear. Sitting on top of the pelvic girdle are all the internal organs such as the intestines, the liver, kidneys and stomach. When the foot hits the ground, especially if you are a heavy runner, the shock wave is transmitted up through the rest of the body. If this seems hard to believe try to remember a time when you stepped off a curb and hit the pavement with a locked, or stiff, leg. It seems as if you could feel the sudden stop all the way up to your teeth.
When I increased my mileage the intestines and organs were forced downward every time my foot hit the ground. This resulted in a continued push against the attachment of the lower abdomen muscle on the pubic bone. A long run will take over three hours of pounding on that attachment. After several long runs I noticed a soreness where the muscle attached to the pubic bone. It reached a point where if I leaned backward my abdominal muscle would just give way and I would almost fall backward. This soreness of the lower abdominal muscle became worse with each long run. It forced me to concentrate on keeping my pelvic girdle level so that the pounding of the intestines against the abdominal wall was reduced. It took some time before this new running posture with a level pelvic girdle became automatic. With the level pelvic girdle the abdominal muscle stopped hurting.
Where a level pelvic girdle also plays a role is with track sprinters. With an anterior pelvic tilt the runner cannot bring the knees up as high. When the sprinter reaches the halfway point, the hamstring muscle begins to tire and tighten. As the sprinter now tries to lengthen the stride there is a strong possibility that the hamstring muscle will tear. If the tear is down lower in the belly of the muscle the cause of the tear might be a tight hamstring. If the tear is up higher underneath the buttocks the cause might be an anterior pelvic tilt. A simple lower abdominal test to see if the abdominal muscle is strong enough to keep the pelvic girdle is needed. The combination of a weak lower abdominal muscle and strong ilio-psoas is one cause of an anterior pelvic tilt. The result can be a torn hamstring.
The second occasion where the anterior pelvic tilt became a problem was when I was teaching at West Point in the rehabilitation area. I had told my supervisor that I did 200 bent knee sit ups and 200 leg lifts daily to make my abdominals strong. My stomach had a slight paunch along with a nice “six pack” of muscles. I thought that the slight outward bulge was because the muscles were bigger from all the exercise. My supervisor asked me to lay on my back, curl up slowly and touch my knees without having the feet secured. My feet shot up in the air. I said, ”Somebody has to hold my feet.” He reminded me the abdominal muscle does not attach to the legs. The abdominal action is flexion of the trunk, not flexion at the hip. All those years of doing bent knee sit ups was because I was using the hip flexion muscle (ilio-psoas) that attaches to the low back and pelvic girdle down to the upper leg bone (femur). The bulge was not from an overdeveloped muscle, but a strain of the abdominal muscle, and actually caused a stretch weakness of the abdominals.
When I tested my lower abdominal strength by lowering my legs from a perpendicular position, and keeping my low back tight against the floor, my back started to come up after only 15 degrees of movement. The abdominals were so stretched out that they could not stabilize the pelvic girdle against the weight of the legs and resulted in an anterior tilt. The anterior tilt resulted in a stretch weakness of the abdominals. The result was a sway back that can lead to problems later on. An anterior pelvic tilt might be a minor problem, but it can be the cause of bigger problems if not corrected.
