Anatomy and Newton's Law of Universal Gravitation (or the affection of gravity towards our muscles)

A few thoughts about animal anatomy.

I've been sketching characters since I was 10 or younger (Pokemons, Dragon Ball, Battle Realms, Warcraft & so much more and 99% of them went into the trash bag, we can talk about this later).

Only in 2015, when I got my first job as a character artist, did I started learning anatomy seriously. I followed a lot of photos, books, and videos that were sent to me by a Dota friend (Thank you VA! You really shifted my life bro, even though we never met and haven’t chatted ever since). I have a list of them in my Discord: https://discord.com/channels/1143187473330090055/1156841963157463050

I think learning from the illustrations and videos of disected deads are very good way to know more about the contructions of our bodies.

But let me tell you, if you put aside your anatomy books and photos; feeling your muscles really yields an extra wonderful info that I learned: Your muscles, as everything else in our atmosphere, don't work on their own but are affected by every single force on planet Earth, especially the gravity. (Thank you Newton).

I find it better to feel and touch my own muscles to learn about their origins, shapes, forms, structures, mechanisms, rigidity and more; especially in their conditions of flexion and extension.

Let's have a scenario (think of the arms as levers):

1. Have your right arm in Position 0 (This is the neutral position for most people), now the biceps and the triceps are both in a Relaxed (Green) state.

Now rotate your forearm as in Position B, touch your biceps and it will tell you that it's in a Contracted (Red) state. This is because Gravity is pulling the mass of your forearm to the ground.

2. Now position your arm parallel to the ground as in Position D. Now due to the force of attraction, you will need to use your triceps. Although Position A and Position D look the same on the paper (imagine I didn't draw the direction of Earth's gravity), D is now not a neutral position anymore.

Due to gravity, you need your arm to be in Position C to relax both your triceps and biceps (now your shoulder is doing the hard work).

3. Now back to Potision 0. You can purposely contract (flex) your muscles to further rotate your forearm to a non-neutral Position A.Now look at A and D, do you see the similarity? You need to use the similar force as A in D to counteract the love of the Earth with your whole arm.

So what's the point here?

TL,DR: Muscle flexion and extension? It depends. Think of the internal and the surrounding forces as you draw anatomy. It's better to internally feel the muscles than just to see them.

The reason I write these words just because NO ONE has ever talked to me about this and I find it's kinda weird. It must be somewhere someone is talking about it.

Let me know what you think, talk about it.