I completely understand you. I was like that for a long time. Ironically, all the athletes and clients I was training (including pros and high-level amateur athletes) were training 4 or even 3 days a week while I thought that I could handle more “because I know a lot”
But the athletes I was training were all progressing a boatload faster than me!
You’d be surprised at how little some of the high-level athletes I worked with, trained.
For example, a member of the national bobsleigh team would lift 3 days a week and do, at the most, 6-9 total work sets per workout. Not per exercise, per workout.
And he squatted 585lbs, front squatted 465lbs, power cleaned 345lbs at a bodyweight of less than 190, lean.
A female powerlifter that I program for is a world record holder in the squat (265kg at a bodyweight of 67kg) lifts every 4th day during contest prep!!!
Training will create central fatigue. Now, central fatigue is NOT to be confused with “feeling tired”. You can feel like a million bucks and suffer from central fatigue.
Central fatigue refers to when the nervous system’s excitatory drive to the muscles is weaker.
And by sending a weaker signal to the muscles, your capacity to recruit fast-twitch fibers and make them fire faster is significantly decreased. This will make any training session done in that state a lot less effective because if those fast-twitch fibers are the ones with the growth potential. If you can’t recruit them as well any potential gain in size, strength and power are decreased by a lot.
So you could still be able to “do the workout” but the result is very little, if any progression.
Now, by adding WODs (counterintuitively, endurance/resistance/conditioning work creates more central fatigue than strength work) you might be burning more calories but you make the next day’s workout less effective.
Not to mention that “burning more calories” by training more also leads, in this case, to more cortisol levels. Over the mid/long term, chronically elevated cortisol levels can make it harder to lose fat by lowering metabolic rate (chronic cortisol elevation decreases the conversion of the T4 thyroid hormone to the T3 one, which results in a slower metabolic rate). So that strategy can backfire.