Build a Big Base with Sweet Spot Training

I would recommend you doing as much sweet spot as you can in 2 hours. Maybe you could get a total of 60 minutes of sweet spot. We never recommend you doing 4 hours indoors. I guess unless you were only 3 - 4 weeks from an A race that was endurance based. But even than it would be a lot to ask.

Here is a great thread on this very subject:

Indoor training: