You’re Not Training Intense Enough
As you become better trained, you need to start pushing your body harder to elicit the same results. You need to push yourself hard at the gym every time you go so that you are actually creating a demand for your body to have to use its energy to push beyond it’s max. Journaling can help you avoid the certain plateaus that come with normal, repetitive training. Challenge yourself to do more work in less time, more weight for the same amount of reps, etc.