This isn't quite right - I do this sport because it is very complete,it incorporates the most important and effective elements of each sport. For 'each sport', to make sense here, you would have to preface this sentence with the names of the sports you are referring to - unless you mean EVERY sport, but then it doesn't make much sense. I assume you want to convey the idea that spinning is an all-round workout that incorporates the best features of a number of other sports/activities?

Yes to say I do is correct. The forms for the verb to do are: I do You do He does She does We do They do. The word each is misspelled.