都去=总去。“都 ”有 always 的意思，and emphasis the tone，u can understand as 每个周六，我总去打篮球

sorry,we can not understand your question.

I learned that 都 goes together with a 每 phrase. You see, 每隔星期六 is in topic position and doesn't effectively modify the verb. You need an adverb to do that, and the correct adverb here is 都. Fiona says you can also write 总是， which is also an adverb.

都 means：both,all,same result 都here indicates that u plays basketball every other weekend as a habitual/repeatitve on intervals/regular action.:)