If you really want to change your cadence, you first have to understand how your stride length is influenced.
2 weeks before the O trials, I had decided that I had tapped out my technique as far as getting faster. I was a 400m guy, who had already qualified and booked my tickets.
I was very strong on the ground, and used to run with more power than technique. It meant I reached a bit far out front, that lowered my hips, and shortened my overall stride, but I was still a long strider, just slower rate. A bit like Alberto Juanterina. Who by the way was the number one at the time.
For the two weeks I focused on dropping my feet in a little shorter, while still staying on the drive phase. My cadence picked up, and my hips stayed a little higher, and my stride got a little longer. I ended up taking 7 / 10s off my pr and medaling. I was expecting to medal anyway, but I finished closer to the front than expected.
A two week fix is not a great fix, but it carried my though the first 150 a lot faster and while I reverted somewhat in the last 150, I was further down the track.
You have to really understand that stride length is impacted by stride speed and hip height. You have to make sure you don't spend your time reaching for the front, which lowers your hips. You have to get your feet in the prime sport under your center of gravity, make sure your drive is hard, and fast, and your hips stay high. It how you lengthen stride.
Every thing you do comes from the jog position. As you apply more power, your hips come up, you need to get your foot down in front a little faster, and you try to force a little more out of your drive leg. A lot of you joggers really don't understand that running is a single support phase and walking a double support. Once you work that out, you will improve your speed. Blocking is a speed killer, and a fatigue monster. Its all about the right balance.