What help sprints out more Half-squats or Full quats ?

as long as you are strengthening muscles relevant to running, does not matter what you do. While I do not provide links, some articles suggest full squats are better, others half or even quarter squats.

I’ve actually read a study on this where it was concluded half squats were indeed more specific and helped sprinting more.

1/2 squats are more sport specific, also you can put on more weight, and can do them faster

just-fly-sports.com

The Truth on Squat Depth for Athletes: A Round Table Discussion with Kelly Baggett, Dave Kerin and Jack Woodrup

You know you have seen it, or maybe are guilty of it yourself: Loading up a barbell with hundreds of

Link:www.just-fly-sports.com/the-truth-on-s...

here are opinions of top coaches

I dont think you need to squat, but generally agree with following:

Jack Woodrup:
I think I am open-minded enough to not be considered a deep squat Nazi, I definitely believe that all athletes wanting to jump higher and run faster should at least learn to squat to at least parallel though . In terms of beginner versus advanced I don’t think there is too much of a difference of what is an appropriate squat depth.
The more pertinent question is choosing the right type of squat for the individual athlete that allows them to comfortably hit a decent depth on their reps. Depending on things like limb and torso length, joint mobility and flexibility, etc, some athletes are better suited to front squats, others are fine with back squats, and of course there are other options as well. These include box squats as well using different types of bar such as the safety bar which is easier for people with shoulder flexibility issues.
There is one circumstance though that I do use partial reps and that is for beginners who have problems with their knee coming in when they do a full squat. Using partial reps in these circumstances and gradually increasing the range of motion allows the athlete to learn good habits under load.

Neither. Humans don't run with both feet planted on the ground.