Im a 400m & 800m runner and basically hit the gym 2-3x a week. I got all my upperbody workout i do like bench, dumbell press, curls, shoulder/military press, pulldowns, etc. For my lower body i do squats but i dont like deadlift so another workout i tried was the leg extension. I really felt a strong burn in my quads even though most people say this workout is useless, also i didn't feel knee pain. So my question is can squats + leg extensions increase my explosiveness and strenght in legs? will it help sprinting speed?