I'm doing summer base mileage right now, about 50 mpw usually around 6:30-6:00 pace with one tempo and one long a week. I'm doing all the stretching I'm supposed to be but my god damn groin and adductors are really sore or overworked or something and I'm concerned i might be in danger of straining something. What the heck is causing this? Muscle imbalance? Poor form? any input is appreciated