The most exciting thing I've read about running in a long time
I expect you'll click the above link to read all about strides and return to this post later. That's okay. Do it!
Strides are very short runs. You jog into them, accelerate over a distance of 75 metres or so to 'near top speed' then ease off to a stop. You then walk until fully recovered (this depends on how fit you are) and repeat. Nate mentions the numerous benefits that come from running strides regularly and often —"every single day if you can." In the 'old days' I used to run strides prior to every track workout and race, which would be roughly three times per week. I've done six 'sessions' of strides (mainly following runs or races) over the past two weeks and am starting to feel some fluidity returning to my running movement.
Strides also fit in perfectly with my mostly steady MAF heart-rate zone training. Being so short (and untimed) they're not stressful in the least. Lactic acid isn't produced and my heart-rate during a stride (if recovery is sufficient) only just reaches the top end of MAF heart-rate (around 130 for me (about 80% of my 162 maximum). After 100 metres of walking between strides my heart-rate has recovered to around 94. My intention is to run strides following every run (and before races) if I can. I'll let you know how it goes.