Wrong Sprinting technique(posture?)

Hi, just a quick question, i’ve never been a sprinter in my life and i was slow and fat, now I’ve got myself in shape and have a 4.78 for 40-yard dash(self timed), I’m still trianing to get myself faster, down to 4.5 or less, but one thing i figured was that after each sprinting workout, my mid-quads feel sore or even lightly injured(hurting) sometimes but never happened to my hamstrings, does that mean my running poster or technique was wrong? thanks

6’0, 190 lbs, 10-12% bf, 29" standing vert