Exactly one month ago I was able to Press 44.5kg
with my Right Arm. I was training everyday at 95% of my 1RM. Then I decided to see if I could make the same gains while training at 90%. The test was a failure and I lost strength. When I resumed training at 95% I used 95% of 44.5kg which was too Heavy because I was weaker but I couldn't accept that I was weaker and thus "cheated with myself" and trained too heavy. At first I could sustain the intensity of the workouts but fatigue is cumulative and today I felt 42.5 was too heavy... I should be able to Press more than 44.5, maybe 45 or 45.5kg but there is no way I can do it with such an effort at 42.5kg.
So in one month I was not able to make progress (30 days lost), in fact my Right Press is weaker than 44.5kg and now I'll need ~20-30 days to go back to 44.5kg (again 20-30 days lost).... and it's only after that I'll be able to make real progress. Overtraining & Undertraining are BIG MISTAKES which can destroy months of progression. I had to do my tests. I don't regret to have tested 90% but it cost me time (50-60 days of progression !!!). It's why I have to restart at around 40.5, 41kg : 95% of 43kg my actual 1RM (did it this evening to be sure this time, I failed at 44 and got 43kg)!
My LEFT Arm which is not overtrained will make progress I think I'll be able to press 46-47kg early in september.