Is it appropriate to stick to workout only with one sport discipline?

Anonymous
There are people who only workout with one and only sport discipline and they dont change routines or anything else, is that good?

I know people who run and they had been doing the sport for many years, participating in races and so on but they dont do other sport disicpline to have more variety in your workout, because they loove so much the discipline they do, they dont want to change it to another thing.

I Heard is not good as you have to make the body do different things, mix it otherwise the body gets to a plateau and stay there and you won't see results. Any truth on this?
Is it appropriate to stick to workout only with one sport discipline?
4 Opinion