I think the debate of the strength of natural vs. relaxed is a tricky one. I have relaxed hair, but because of this site I have learned and adopted some very healthy hair practices. Which has resulted in very healthy hair for me. While the trend is now swinging toward going natural--and I applaud and respect those who can, I don't think that I personally would be able to pull that off simply because my natural hair would require a heat source like a flat iron to get it at least so I could comb through it and far more manipulation than it requires now as relaxed hair. My hair texture is what it is and that is what I think dictates how you can judge natural versus relaxed on some levels. I remember the days of natural hair BEFORE I was relaxed many, many years ago and it was tough. Granted flat irons and the like have come a long way, but...
I think that relaxed or natural once you find what works for you, stick with that and most of all LISTEN TO YOUR HAIR. I can tell you that if I had natural hair I would NEVER be able to condition wash the way I can with relaxed hair. This practice alone has contributed to a healthy scalp for me. A healthy scalp equals healthy hair. I have also learned to sleep with my hair covered, and I have certainly discovered the joys of coconut oil which has proven to be extremely moisturizing and rich. This along with a healthy diet and exercise have given me healthy hair, and I am a woman of a certain age--over 40. Well over 40.
My hair is now BSL and I can tell you that never in my life--even as a natural haired person in my teen years--did I ever have hair this long.
So I've said all of this to say, that the strength of your hair--and this is only my opinion--will come from how well you take care of it. Whether you are relaxed or natural is of no consequence. This is my opinion if I may say so.