Why does indoor triathlon training matter?

As the weather gets colder, more people are starting to take their bikes indoors for the winter. There are a few different categories these people fall into. The one I hear most is “It’s the offseason, so I am going to take the winter off.” That training strategy doesn’t sound too promising heading into the next season. In the Spring when they get back on their bikes, their first reaction is usually wondering why they are slower than the previous season and out of breath so q