There is much to be said for the effect that participating in music has on your health.
이문장 끊어서 해석을하면

There is much to be said / for the effect /that participating in music //hason your health.
많이 말해지는것이 있다/ 효과에 대해/ 음악에 참여하는/ has on your health ????

아니면 이렇게 끊나요(제대로 끊은게 어느것인지)
There is much to be said / for the effect /that participating in music has//on your health.

has on = has effect on 이 생략된 거라고 하던데
어떻게 저런식으로 생각할수 있는지

그리고 지금 has 가 어디에 걸리고 있나요