Please look at the video and learn the basics of footstrike. Posture, and how to use the gears.

I call the gears

1st gear- Heel strike, slowing down (Downhill etc)

2nd gear- Mid strike, best gear, very economical

3rd Gear, front part fo the foot, speed injection (Uphill etc)

https://www.youtube.com/watch?v=Rt9hgtFzZk0

Enjoy