When I look back at my running career, it was shaped by different coaches along the way. Every coach had the (roughly) same goal: make me as fast as possible.
If you follow elite track athletes on social media, you'll notice a trend in the next few months...altitude camp! A lot of groups do 3-5 week trips to altitude before the start of their season (NorCal, Little Wing), or live at high elevations year round (Steph Rothstein, Kara Goucher!).