For the sake of feedback from a diversity of people…
The more I train through the years, the more I realize that doing absolutely nothing (non-active recovery versus active) makes me feel like crap, and picking up a training session the next time is more difficult… (Which is why I enjoy double sessions too, even if the morning one is a pure warm up, with a quick stretch, drills, strides, and go home).
Easy biking home for 15’ after every single training has also helped me a lot, especially after lactic sessions on the track.
With some intense weight room sessions now during a very cold winter in Milan (and no chance to run fast on the track), muscle soreness and tightness goes wonderfully with what could be described as ‘contrast therapy’ (that you guys speak about), but with the aid of alternating sauna and cold baths. (so wonderful… and mentally ‘easier’ than switching the temperature yourself in a shower).