Raising the knee is as difficult as you make it. There is a slight increase in difficulty with the knee up, but there should be tremendous effort to pull the knee as high as possible during the hold.
Cues:
- Shift your weight to one side and raise your knee as high as possible without leaning back
- Keep the standing leg locked
Mistakes:
- Lazy knee lift
- Leaning back
- Bending the standing knee