Is training to failure a safe and effective method for improving athletic performance?

I will talk from experience, I train a US RECORD HOLDER IN SWIMMING. Also I have trained many others. We not only believe in working to failure sometimes but actually overtraining til you can’t sleep and keep overtraining for weeks then have mood swings, immune system goes down etc. but then 2-3 days after all this the body will fly up faster than anything you have ever seen even while you are still “overtraining” according to the common definition of overtraining. Which I agree it is overtraining. You just have to go through the bad phase. All the studies out there quit when the bad side effects start happening and especially as the side effects are getting worse. This is not for good for 99.5% of the population will have no need for this. But to the select elite that need to break plateaus and excel to world record heights. Then it is useful. I will not give the details on how to do this because people pay a lot for this info and are very happy. And I don’t train anyone on steroids. Yes it will get worse and I did as well, I went backwards for about 4 days of an overtraining routine but afterwards flew a head so fast many thought I was on steroids. Yes, the personal doing this is risking a lot and has to get a massage everyday and eat very healthy.
I gave Shawn a thumb up for his answer in 217 except for the “Microcycles” part. What I am talking about that is beneficial for .05 percent of the population should be carried on for 6 weeks. DO NOT TRY THIS AT HOME!!!