eli5: Why do people who are actually strong look different than bodybuilders who train all week?
In: Biology
We do not quite know all the detals of the human anatomy. But in order to become strong you can either make your muscles bigger or you can increase their efficiency. There are various techniques to train for each of these traits. The best way to train if you just want to become strong is to increase the muscles efficiency so that a smaller muscles can lift more weight on its own. However there is a limit to this so at some point you need to increase the mass of the muscle as well. But bodybuilders do not care about how strong they actually are and will build muscle mass without caring about their effeciency. You can usually notice some difference in the looks between a rather compact efficient muscle and one that is just for show.
Another difference is that when people train for strength they usually only train the muscles they need. So they will get some strong muscles and some weaker muscles depending on how they are training. However a bodybuilder will train muscles that is easier to show off. It is much more estetical to be able to show each individual muscle instead of having the smaller muscles hidden by the big muscles. So body builders will often train a lot with smaller muscle groups in order to better show these off. It may even be desirable to reduce the size of some of the bigger muscles so that you can show off the smaller ones better.
And that also brings us to the body fat and the water content. Bodybuilders will make sure to reduce the fat percentage, often to unhealthy levels. This is so that there is no fat between the different muscles which might ruin their looks. People who are actually strong want to have a fair bit of fat so that they can keep their energy levels up through long training sessions and competitions. Similarly they want to stay hydrated so they are able to perform their best. But this means that their muscles are often hidden by a layer of fat. A lot of strong people might directly look fat with big bellies and other features common with fat people. However part of this is that a lot of the volume that would be taken up by fat is taken up by the muscles and part of it is that they need the fat to stay healthy.
Latest Answers