There's a fine line between stretching yourself and straining yourself. Straining implies that you've put a little too much into what you're doing while stretching implies that you're going just a little further. Stretching helps you get better while straining destroys you. Now when I talk about stretching yourself, I'm not just talking about the importance of stretching before and after your runs, I'm talking about putting yourself slightly beyond what you're used to doing and training to improve. On Tuesday, I went out for the hard run where I pushed myself hard. Now it seems as if the right thing to do would be to take a rest the next day, but instead, I opted out and decided I'd stretch myself just a little bit and go a medium distance. I went out, and gave myself a minimum of 40 min to a maximum of 1:20 of running. During the run, I thought about how I wanted to grow, and decided that I needed to get my longer distances down if I was going to train for an ultra marathon, so I went with the 1:20, running out 40 minutes and hoping I can run back faster. Of course, I didn't go all out and try to run hard both ways the day after running a speed work out. Instead, I went pretty easily. Altogether, I ran 9.9 miles in 1:16:21, an average of 7:42 min/mile.
Stretching yourself enables you to grow, and you only grow the direction you stretch yourself. Knowing that, it's important to know the directions you want to grow, so that you can stretch yourself. Also, it's important to not stretch yourself in multiple directions at once because in doing so, you can stretch yourself too much in different directions so that you don't stretch too much at all, becoming a jack of all trades and masters of none. Focus on what you want to be and stretch yourself in that way, and you will grow fast.