On a basic level, this
is true and, as you are well aware by now, I believe the fundamental thing we can all do to thrive into later life is to add muscle, lots of it, and maintain mobility of our bodies.
Taking this deeper though, each of the exercises above do train the muscles they are named after, however, done right they train, to some level, nearly every other one in the body too.
A standing bicep curl, done right, is accompanied with a contraction of the Glutes, torso muscles and stabilisation of the back, shoulder, neck and chest muscles. There is also a load on EVERY one of your 100 trillion cells, and this load creates a response.
In short, ANY load we carry, hold, push or pull against 'trains' our muscles.
Training our muscles makes us stronger if this extra load is consistent.
The adaptive and intricate body we all have will 'assume' that any load it comes under frequently is here to stay so it will add muscle, strengthen tendons and bones and make itself more mobile to deal with these loads.
Adding muscle goes FAR deeper than buns and
It doesn't have to be 'beast mode' and 'crush it' in the gym everyday.
You can start small, really small and just repeat as much as possible for you. IT IS ALL PROGRESS!
Your 'small' will soon become not that small at all
Try really focusing on one walk a week one eve, for 30 min or so. Do this consistently for a couple of weeks and then come back after a month and tell me that its not increased to 4/5/ eves a week and you feel much better!
It can just start with thinking about reducing using THINGS to support your body less and getting it to support ITSELF more.
Think about how we respond to gravity.
EVERY muscle, bone, joint and ligament have an infinite number of positions as we move