Several years ago I developed a nagging pain on the right side of my pelvis, in the crease between the top of my thigh and my pubic area. Clearly an overuse condition related to running, the pain got so bad that I had to stop running completely. It went away for a while and then returned with a vengeance after I resumed full training. Fearing that I had developed a sports hernia, I went to see a doctor about it, but he diagnosed hip flexor tendonitis.
Later, when rehabilitating an unrelated injury, a physical therapist told me I had extremely tight hip flexors (a common problem in runners) and suggested I start an intensive stretching program to lengthen them. Very soon thereafter another physical therapist analyzed my gait and told me that my stride was too short because I was unable to hyperextend my hips normally, probably due to those tight hip flexors. The two therapists (who knew each other) agreed that this muscle imbalance was probably the cause of my tendonitis.
Whether because of the stretching or other changes that I made (most especially to my gait), I was able to control my pelvic pain (which eventually emerged on my left side, as well) enough to train as I pleased, but it was a constant source of discomfort and became borderline debilitating during my heaviest periods of training and in my hardest, longest workouts. Indeed, it nearly took me out of the California International Marathon last year.
Recently, on a hunch, I decided to test whether making a specific change to my stride would ameliorate the problem. Since the first time I saw myself running on videotape as a high school junior I have known that I run in a sort of seated position, with my pelvis tilted forward-a posture that you might expect in someone with very tight hip flexors, which contantly want to fold the trunk toward the thigh, and another very common issue in runners. I wondered what would happen if I forced myelf out of this position by pressing my hips forward, neutralizing the position of my pelvis and thus making it easier to hyperextend my hips to lengthen my stride.
I began playing around with proprioceptive cues that would enable me to sustain this change. Consciously pressing my hips forward worked well, and so did running tall, or imaging my head being pulled skyward by a wire. Interestingly, in this position I immediately felt my hip flexors being forced to stretch more, as they were having to work from a more lengthened position compared to the contracted position they were used to working in. But while I felt more stretch in these muscles, I actually felt less strain. My hypothesis is that to facilitate my new posture, my brain has relaxed my hip flexors instead of holding tension in them as it normally does. Without this tension, my hip flexors no longer resist the lengthening they must undergo to allow my hips to extend. A tug-o-war has ceased.
This experience strengthens my belief that stride improvements trump stretching and strengthening exercises with respect to overcoming and preventing recurrence of injuries. Tight and weak muscles only cause injuries inasmuch as they alter the stride in bad ways. And no amount of stretching and strengthening will fix stride flaws on their own. There must be a concious effort to run differently.
The physical therapist who told me to stretch my hip flexors was not wrong to do so, but what she did not understand is that muscle tightness is not a matter of a muscle being structurally too short. Muscles can't shrink in that sense any more than bones can shorten. Tightness is, rather, a matter of your brain holding the muscle in a shortened position-keeping it constantly semi-contracted. Traditional stretching exercises are not the best way to train your brain to relax a tight muscle, especially in the context of complex movements such as running. What you really have to do is trick your brain into letting the tight muscle relax by changing something about the way you move so that your brain sort of forgets to hold tension in the tight muscle and then discovers that no harm is done in the process (as holding tension is essentially a self-protective mechanism) and continues to allow it.
It's only been a few days since I made this discovery. I'm still at the stage where I have to concentrate on pressing my hips forward with every stride or else I fall back into sitting. But I think I'm onto something and I am very eager to see whether the pain in my pelvis slowly diminishes as I continue. Maybe someday I will no longer wince when I wake up in the middle of the night having to pee and contract my hip flexors to sit up in the bed.