I've done track work and felt that pain, but nothing compares to these 30-second sprints. Man. Back at it today out on the Normandale Park pitch. Maybe doing these intervals after doing bike intervals in the morning wasn't the best idea. And yet, I had to get out for a run, what with the sun burning bright and the air carrying, well, OK, not a hint of spring, but a hint of a suggestion of spring. So I moved tomorrow's planned right-out-of-bed sprint session to this afternoon. (Afternoon sunshine vs. morning chill? That wasn't a tough call, and it was so nice. I wore just one layer, my Boston Marathon tech shirt. My first one-layer run of the year!)
Start with a 30-minute warm-up, some loping around the park, the dog people and the their dogs coming and going. Then onto the 10 sprints. This time I had my Garmin. I didn't think to hit the lap button for each sprint until the last two, but it was mostly the heart-rate data that I was interested in anyway. With each sprint, my heart rate hit a higher peak—and didn't come down as far—until flattening out at No. 6, in the low 170s. My speed was pretty consistent throughout, generally peaking around 13.5 mph, although on the second-to-last run I kind of dogged it. But I fired it up for the last one, running hard all the way through the 30 seconds and finishing gasping and heaving for a minute or two before winding down with 15 minutes of very slow jogging. Killer workout, but these are the ones that convince me (fool me?) that I'm doing something big, crazy, worthwhile, and that progress is being made.
(And, yeah, if you study the chart above, you'll see I did nine sprints, not 10. I miscounted. Really—I could have done one more!)