Sean learning glute bridges and holding for time at Snap Fitness 24-7 in Marlton, NJ. Once the client can hold this position (straight line from shoulders to knees) for 90 seconds, we progress into leg curls with the body in the same position. Most lifters would just strap in and do whatever exercise they could think of. The problem with that is they haven't built a good enough base by understanding how to progress and regress movements. This needs to be learned without movement first. This is also another way to keep your body challenged while also progressing....instead of jumping right to step 10 and not forcing your body to adapt over time.