The Spire Stone will track many but not all fitness activities.
Spire currently tracks steps and can identify consecutive periods of active time periods. For example, Spire will tell you how many steps you ran and will also tell you how long you've been consistently moving before breaking a streak of, say, 20 minutes.
Spire currently will not identify certain physical activities that do not resemble walking/running – like bicycling and swimming. However, we are working on updating the app to distinguish these activities as well.