Hi all - looking for suggestions for Fitness Blender workout videos that provide a high intensity but low impact cardio workout. I have a bad knee (broke it badly in a ski racing accident some years ago, and am developing arthritis in it now), but am otherwise quite fit. I am trying to maintain my cardiovascular fitness until I can go back to spin class at my gym, but am finding that many of the low intensity (or high intensity with low impact mods) don't provide enough of a workout to maintain fitness. Would appreciate any advice or links you may have to offer. Thanks!