Will There Ever Be A Straight-Forward Answer To Muscle Soreness?

Over the past couple weeks, I've really learned a lot about the muscular system and human anatomy. Unfortunately, I did not get straight to the answer of finding out if muscles got worked hard enough even without being sore the next day. I have found answers leading me closer to the final result, but it sounds like the answer would be yes. The only case I can think of where you would not have muscle gain, is when you don't put in enough work, or you didn't do the exercise "correctly." However, it doesn't always need to be strenuous amounts of exercise.

                                                 Image: mdpi.com
My thinking has progressed because I start questioning about more parts of the body and get more curious, rather than jut trying to ask a yes or no question. This question involves the understanding of the human anatomy and the biology, and I really hope one day it will be easy enough for me to know this criteria like the back of my hand. I still wonder if there are studies that prove that lactate has anything to do with delayed onset muscles soreness (DOMS).

                                                  Image: DailyHunt
Now that I have gained a greater understanding of this topic, I can argue that you do not always need to be sore the next day after a workout to have muscle gain. I understand that everybody is different, but this seems to be the most credible answer. Before starting this project, I really thought that it was better to be a little sore to know you've put in a good workout. However, I'm glad to hear that's not always the case!