The deep breathing while running is definitely helping my performance. I ran a 10K on the treadmill today, the first time since the Cap 10K on 3/27 that I've run a full 6.2 miles. I finished it just 27 seconds short of my all-time best treadmill 10K time, completely turning my attitude around. I'm considering signing up for a half marathon around the time of my 40th birthday to help give me motivation for working out and to give myself a birthday present of accomplishing something I've never done before. Yesterday, I thought that I wouldn't do it because it seems so far beyond my reach since I haven't run further than 5K in over 3 months. Today, I think I will do it because I'm pretty sure I can if I work hard in the intervening months.
So in 24 hours, I went from thinking that I probably couldn't even finish a 10K right now to turning in one of my best times, with a time on the second half that beats my best 5K time by 10 seconds. I can do this. Of course I can do this!
My biggest hurdle in running isn't my knee. It isn't my lungs. It's my head.