Anaku

Any bodyweight exercise is helpful to increase ones general strength. However, to be proficient in MA one needs to use their whole body in a dynamic way. Traditionally martial strength and awareness was fostered by some sort of qi gong training. Unfortunately there are a lot of people teaching it that have no idea what they are doing and done incorrectly can severely damage ones health. Lastly, a true martial art uses leverage, strategy, timing and skill to overcome an opponent not raw strength.

Things sometimes happen for a reason. I don't know how experienced you are but periodic breaks from any subject can yield knowledge and a deeper understanding. All martial arts have something to offer as well, so maybe it's time for a change?

Joint injuries are very common among older karateka. Ballistic performance will blow out the joints unless one is taught to not fully extend your limbs and or not use full power. In the old days many martial artists lived active full lives well into eighties. More recently this is not so true anymore... In Okinawan kata's there are only front kick and in some styles side kick. All the other kicks were added later...

Two of my old teacher's favorite sayings were, "start second, finish first", and "don't move unless your opponent moves." Intent can be felt and responded to. This is Zen.

Karateka should be focused on cultivating a peaceful and calm (quiet) mind, and self perfection of character. I've known a few real life spec ops guys and it requires a different mindset.

I don't think anyone has found the answer to making sparring translate to self defense. It doesn't hurt to spar once you have developed control but the founders did not spar at all. Sometimes they fought in challenge matches, defended themselves or just got into a fight. It is true that once you've done something you are less nervous about it and I think this is why some picked fights in the old days.

It can be used to escape a wrist grab as well as pulling your foe into a strike or unbalancing them.