My assistant executive director was singing the praises of XC Skiing today. He thinks it would be perfect for me since I love to be outdoors, exercise and endurance activities. He insisted that falls are quite rare since you are on a plowed track of different levels and feet never leave the ground, and that it's quite low impact for the knees.

What he describes is not what I think of when I think about cross-country skiing. Comments, thoughts on what he said?