use case relationship generalization

It is perfectly legit to have a generalisation between use cases. The generalisation arrow should then be a big hollow triangle:

But generalisation makes only sense if the more specialized case is some kind of the more general one. In your case "Chose health goal" is about choosing. But "maintaining weight" is not about choosing. But you could easily improve it:

• either consider to use an «extends» with a dashed arrow (but again, is gaining muscle really an extension of the choice behavior?),
• or reconsidering the definition of the general use case, to make it indeed something that generalises the specialised examples e.g: "pursuing health objective".

If I had to chose between the two, I'd use the second one. If I had to model it myself, I'd keep it simple with the generalisation, but not showing any specialisation, and avoid any detail that would be easier described in the narrative.

(Not related: 1) Sign-out, like Login shouldn't be a use case; 2) The «extends» arrow seems to be in the wrong direction)

Generalization in use case relationships means creating a parent use case that holds the shared behaviors of multiple child use cases. It promotes reuse and simplifies models by allowing common functionality to be defined once in the general use case. This functionality is shared from more specific use cases, reducing redundancy and improving clarity.