The six sports set to feature in the game at launch are wake racing, climbing, football, target shooting, bowling and tennis.
"We had over 30 prototypes of different sports, right down to things like horse racing and fishing," Isaac told CVG during a recent visit to the studio's Twycross HQ.
"So we built all of these prototypes and then built this big graph and rated each sport. Not just for fun, but also appeal for different ages, whether it showed off the sensor well and also telemetry from the previous Kinect Sports instalments and what people liked. From that data we whittled our list down to the six sports we have today.
"We wanted our sports to complement each other and we've found that everyone who plays the game prefers different sports."
On the subject of the studio's DLC plans for the game, Isaac added: "We have a number of scenarios for how it might play out. For now though we think we have a very robust offering in the short-term. We still have some unfinished business, but if we could all get in what we wanted the game would be two or three times the size it is."
Kinect Sport Rivals was originally scheduled to be a console launch title in November 2013, but was delayed to give Rare extra time to polish the game and release it without compromising its quality.
In February, Microsoft announced a Kinect Sports Rivals release date of April 8 in North America and Australia, and April 11 in Europe.