When doing run outs during warm up I can feel this tremendous lift off the ground, but when going flat out it’s not there anymore - or at least I can not feel it.
Certainly such as this man was here!
However, I understand the point. My athletes tend to rush “the order of things” on occasion. When instructed to “move from the blocks” and “rotate under & up”, is when performance is heightened. They also come back with a feeling of rapid bouncing.
Now if I can only get them to it without the cues! 
I suspect you are attempting to push when you go “faster” (probably only harder), let things go and see what happens.
The old coaching trick was to get an athlete to go “100%” for a timed 60 (or some such distance), then get him to take 10% off the effort, and time him again. most times the 90% effort was, in fact, a lot faster, to the surprise of the athlete.
I tend to notice that as well, Charlie. When I am doing run throughs from blocks at a less than maximal effort, I often feel that I run much faster than if I am instructed to go Max effort. Most of the time when I run a 100m in competition (have only ran a handful), I tend to tighten up and try to push-- which ruins my whole race. I have yet to run a smooth 100m. My best is 11.4h on dirt when tightening up; I think if I stay relaxed and let it come like you say, a better effort lay ahead of me. Same with the 200m!
Yes, that’s what I had decided to try next time. My problem has been no one to time me, but I have arranged for that now.
He certainly looks as good as I feel I am:) Now I just have to carry that over into higher intensities.
To tell the truth I have only recently begun allowing full movement around the shoulders and hips, realising I was restricting movement by trying to “look good” - in short I was pussyfooting, even at “full speed”.
in that video with ben when he bring his arm in front it looks like its bent at 90degrees but when he brings it back it looks like close to 150-60 degrees/almost straight. is this correct form? I always kept the 90 degree angle througout my sprinting
sorrry if i hijacked the thread
The faster the runner and the more powerful the arm sweep, the more the arm will be forced to open up at the back, despite the athlete’s effort to hold a 90d angle. As this is not deliberate, it still generates an elastic stretch receptor response, helping to fire the arm back.
I’m happy to say that the lift is there now. I just held back a bit at the start and the rest took care of itself. For the first time in three years I now have some bounce in my steps 
Surprisingly I found that during my better runs the thumb and the index finger would involuntarily meet and form an ‘o’, something that has never happened before. It felt natural though and always meant I had hit top-speed.