Gym vs. Nature psychological differences
Some youtubers don't quite understand the 'training montage', when Rocky trains with 'natural methods', and Drago trains with 'computerized gym methods' that are tailored to him.
Forgetting the whole 'injection' stuff for now, let's examine the psychological differences that are very important, but many viewers don't seem to understand.
The gym gives you a 'tailored' experience that can be adjusted and fluctuated based on your mood, your growth, your 'oxygen' that day (there's a saying about having 'bad oxygen' a day when you are feeling weaker than some other days) and so on.
Nature doesn't give you ANY 'adjustment factors', which creates a stronger spirit. When you can't adjust the weight of a log you are hauling, you know you HAVE TO just push through, you have no other choice. It doesn't feel safe, so it pushes you further.
In a gym, you can adjust your weight if you feel it's too heavy, so you are never in any danger. This makes your spirit weak, because you can always meet your 'comfort zone'. You have a safety net, in essence, that you don't have in the nature.
In the natural way, the log is what you have, and that's it. Either you push through, give up or die.
In the gym, that exact same weight can feel 'too much', so your trainer adjusts it so it's easier for you. Now you can safely do your training. But you never had to overcome your physical limitations by using the power of your spirit. Your spirit does not grow stronger.
The gym is 'better' in the sense that you have specialized, customized training programme that you can follow to a tee and do all that's 'required of you' and that's that. Great workout.
However, the nature is 'unpredictable' - sometimes the log or whatnot can be 'too heavy' for you. You can't adjust it. You have to take the 'too heavy' together with the 'too light' and 'perfect' as well. This forces you to ADAPT and work through things that you CAN'T BE SURE you can.
This is the main difference - Rocky trains his SPIRIT as well as his body, exactly because the training method is not as exact and has more random variables, like those horse wagons or whatever - he doesn't know their exact weight, he just knows those horses and people need help (I won't get into the whole 'animal slavery' thing right now), and HAS to overcome WHATEVER the weight is to help them. So he has no choice, he has to muster enough spirit through the fear of 'what if it is too heavy and I can't do it' and just push forward.
Drago NEVER has to encounter this fear, because he's being trained as a robot - only the physical side and techniques, his spirit gets weaker while his muscles get stronger. He doesn't have to face any fears or overcome any unknowns. Everything is scientific, pre-calculated, computer-perfect.
Some youtubers watch this movie and think about it and then say stupid things like 'I think the gym is better and more efficient' without realizing just how much MORE this natural method forces someone like Rocky to overcome. It's not just about the muscles - both already have enough muscles to beat up each other 20 times over. Both already know enough about boxing, they have enough reflexes, training, know-how, etc.
The Russians simply want to 'perfect' their machine and keep it in tip-top shape - physically. They want to BRUTEFORCE every fight and make the motherland proud of their little experiment (they don't care if it's Drago or not, they just have a muscular experiment, not a human being).
They don't care about how he fights, if he his spirit can overcome things - they just care about how hard he hits, how many pounds he delivers, that he DESTROYS anything he hits. That's where it ends for them.
Rocky, however, has more human spirit and emotional investment in it. It's a bit like a situation where someone insults a dog for not being able to catch a rabbit, and this surprisingly sentient dog responds: "It's a different thing to run for your life than to run after a meal".
(Even though fundamentally, that is also part of 'survival', the dog won't die just because he misses a meal, but the rabbit absolutely will die if the dog catches him).
Psychologically, these are two completely different.. I can't even say 'people', because Drago only becomes human near the end, Rocky is the only human in this fight.
It's as the song lyrics explain earlier in the movie; it's the SPIRIT that wins the fight, not the muscles, not the technique. Rocky learns from the natural training to overcome his own fear and hang-ups, push through scary situations and 'impossible odds', whereas Drago learns 'how to punch a bit harder' and 'how to have a bit stronger muscles'.
People often miss this kind of subtleties in movies, because 'it's just a movie' or 'it's just a silly sports movie' or whatnot. However, this movie is a celebration of the human spirit versus just the mere physical bruteforce - you can't bruteforce everything, and you HAVE to face your fears and hang-ups at some point.