Having trouble transitioning from acceleration to top speed

hello. this is a quote from an old topic on CF here but i’m having the same problem…

"Basically, I find that when I get into an upright sprinting form from blocks (as opposed to a gradual build-up, or something like a 30m fly) sometimes, (most of the time, not always) I am unable to get into my stride properly.[b]

For example, last night I ran the 100m in a race. I had a decent block start, but when I got into my upright running form I could feel my heels coming up way too high behind me and my knees dropping too low in front of me. In the moment, I felt like I couldn’t do anything to adjust my form. I stayed loose and didn’t panic, but still ended up running pretty poorly."
[/b]
It felt kind of like falling forwards and I can feel it in my quads after the run.
I’m thinking some mental cues to focus on would be helpful. Any tips would be much appreciated.