Looks like a classic hip flexor tear/strain. It is exactly like the one my nephew Kris the polevaulter experienced early in his career, a sudden pop or grind with the leg extended backward. I'm fairly confident after talking with Johnny B. (fellow sprinter), that is not a joint injury like a torn labrum which usually happens over time, not in one shot. It's definitely sore but not as bad as the ham tear I had in '12. I think some of the trauma was deep, near the bone and the pain is on the upper part of the thigh, but I can feel it extending down my femur, like some of the muscle was pulled away from the bone or something. I iced yesterday and today, now I'm in the hot tub gently massaging and lightly stretching. I'm predicting I'll be back on the track by Saturday for some foundation work.
Equipment
My racing shoe of choice (shown below) - is last year's model Puma evoSpeed Sprint LTD is not being made this year in my size (6.5) and it was almost impossible to find last year's model shoe anywhere - especially in my size. Extremely rare! I have 2 pairs, one green and one black, and I've been wearing these since last season. I'm afraid the right outside spike hole will get stripped - like what happened on my previous pair - since that spike fell out completely on Friday's 200m race. Well, I managed to find a pair in my size in England on this cryptic shady website that I hope is legit.... since it had this shoe listed in stock with free shipping for $49. I paid with Paypal... hope I don't get ripped off and I get the right shoe. I did get an invoice by email but their website gives no physical address or phone number. I'm really skeptical of this vendor, we'll see.
I like these shoes since they fit me better than the Nike's, they're an ounce lighter, and they accept the Nike risers. Every half inch helps.