Almost 2 years ago, when I was ramping up my training and had hit 30-40 miles per week for about 6 weeks, I developed a sudden groin pain that would not go away, even with rest. I eventually had hernia surgery, but even after the surgery and patient healing, nothing had changed.
My right groin had a weakened feeling, not a sharp pain, but strong enough to deter me from trying to run, as I felt any exertion would bring back the pain.
Finally after over a year, I did the Beachbody P90X extreme home fitness program. I lost weight, gained strength, and was able to start running again. I was unable to explain why, but it seemed that the P90X workouts had cuted me.
Well I recently found this post and this post on a running message board answerred by Dr. Nilesh Shah. Both posts seem to indicate that groin pain in runners may be caused by a core imbalance, or a weakness in the core area.
Since P90X certainly strengthens the core, this may explain my miracle cure!