Today's Running Record

I've been running at a 4-minute pace for 18 consecutive days now. Before, I was stuck at a 5-minute pace for a long time because I didn't push myself. Now, my training involves high-intensity interval training for runners, specifically Fartlek (speed play). It's 1 minute of high speed followed by 1 minute of slow speed. During the high-speed intervals, one lap of the 200m track takes about 50 seconds. I just want to break my own limits, and the biggest benefit is the afterburn effect – fat continues to burn even after I stop exercising.