When looking around Civitai, I was looking for a more general embedding for a bodybuilder's body type, and there was one, which was a physique model. Almost all the muscle ones are loras, for obvious reasons - they get much stronger results.
However, I used a lot of Regional Prompter when trying to create images, which means that loras aren't always great for getting different characters in the same image without inpainting. Latent isn't always ideal for various reasons (it's slow, it's buggy, the changing of loras mid image often breaks the background).
However, an embedding can be added to a complicatedd prompt a lot easier in Regional Prompter to get the desired effect. To chose one I regularly do - get an extremnely buff guy standing next to someone without them being buff too due to the lora spilling over too much.
Use a little way down the prompt to get a best effect.