My squat strength increases or remains the same, never goes down. The same with my bench strength.
However my pull up strength tends to oscillate, some months I'm incredibly weak and some months I'm too strong for my frame.
No injuries happening and I train all body parts the same. Actually I do just 5 exercises; squats,bench,calf raises,windshield wipers and weighted pull ups.
Last month I was able to do 3 sets of 10 repetitions with 33 kilograms, but now it went down to 28 kgs , if I try to use 33kg I can't finish all reps.
This is the second time it happens, and it only happened with pull ups.
How do I train so that my strength is always peaked and never oscillates? It is important for my mental state to not go down in strength, even if it might seem normal to others, I don't like putting effort into things just to get weaker.
Sleep and food is not a factor, I have a monotonous life as a single adult male. I always cook the same foods and sleeping became my best skill, I can fall asleep the moment I shut my eyes and rest my head on the pillow and wake up every morning to go to work feeling well rested.
I don't even remember the last day I had a bad night or skipped/cheated a meal.