I've noticed as I've used skimble more that exercises that I used to find really burn are now much easier e.g. Russians Twists.
But an interesting thing is that occassionally I've found that exercises I used to find easier have become harder! My theory is that as my strength increases so does my form - so more challenging exercises that I didn't have the strength to do properly I suddenly start doing correctly. Thus, they become MORE difficult. Has anyone else experienced this? If so with what exercises?