I run three separate training blocks: conditioning, strength, and hypertrophy. However, I am introducing a new "Bulletproofing Block." Anyway, I am coming off a great conditioning block. Here's how I know it's over, I hit my goal and I am starting to feel terrible.
For those who have competed in particular powerlifting or strongman, you should feel pretty trashed once the contest is over. Most experienced lifters will not dive headfirst back into competitive training.
Because I don't really compete anymore, I don't always know where to end a block. The most sense would be when I test. However, I don't always test at the end of the block. It's like with my mile time. I felt good one day and just went for it and hit my goal. Then I carried on with the block.
I just finished my third block and my body is fighting me. For me, that's a good sign to switch things up. I used to wonder how long should I run a block. Wonder no more, my body seems to know better than my brain.