OK so I am a freshman at a fairly competitive D3 school with PR's of 8:45 (3k), 4:09 (1500), and 25:50 (8k XC). My problem is that I cannot seem to get my heart rate up during workouts and even races (i.e. my legs give out WAAYY before my lungs, heart, etc. even feel tired). Seriously, during a recent workout I was running as fast as my legs would let me, but I was nowhere near Oxygen debt or anything. My question is: how do I fix this so that my legs can keep up with my lungs?
FYI - I have been doing 80-100mi/week since about mid-July and yes, I do strides (6-8 x 50m about 2-3 times/week). Also, my resting HR is ~38-40 if that helps.