Definitely skill.
Ok, I’m going to diagnose your kicking problem over the internet. When you ‘stalled’ you had started to bicycle the legs. What that means is that as your foot was going up, your knee was going down and vice versa. So upper leg was going in the opposite direction of the lower leg and they were cancelling each other out.
Some drills for this:
- Kicking from hip with knees locked like you are in a cast.
- Kicking from knees with no hip (hold buoy between thighs to help)
- Kick with fins…for some reason using fins always fixes this