As a rather large woman who has climbed the falls, I can speak from experience. Yes, it was more difficult for me than other fitter people, but I was able to do it without too much trouble. The hardest part was that some of the step ups were quite steep. I have very short legs, and found some of it difficul, but the guides are there to help when needed. However, I will say that my leg muscles were so sore afterward (for about 3-4 days!!). Even this pain could not damper my enthusiasm - it was awesome and I'd do it again in a heartbeat.