i strained either the adductor magnus or gracilis, its a slight strain my ART guy says. It hurts when i bring my knees up 90 degrees and flexed and if i move it while its flexed 90 degrees i can feel its pull.
only when doing fast forceful sprinting i feel it when the support leg is about to be brought back to high knee in front of body that transition i feel the most.
Once you get the injury healed, it sounds like you may need to work on activating your glutes. When you improperly (or in some cases, don't at all) activate the glutes, your adductors are used kind of like a hip flexor, and it in turn it becomes over stressed.