I believe push up / press up is more common and powerful
I really wana know how to strengthen my body
push up or barbells???
i weigh 84 kgs. and 186 cms tall..
what loads should i lift???
Pushups are fine, they just use body weight, so it's hard to really dial in what weight is most challenging for you. Plus it's a little easier to stabilize your body, so you aren't quite working the same amount of muscles.
Barbells use more stabilizer muscles in the arms and chest. They are a much better whole body work out and you can get to the specified weights.
ZDumbells are even better because you can't help your left hand stabilize with your right hand.
Machines are good for isolating a specific muscle, but you lose alot of the secondary and stabilizing muscles with them.