This was my second week doing the Tabata workouts. Still stuck at 4 cycles. The protocol calls for 20 seconds at 170% V02Max which, given the lack of access to a lab and/or proper equipment, is a bit difficult to do. The first time, I went all out and later on, calculated it using the Internet and some fuzzy logic. So, this is how I went about it. Using a 5:55 min/mile as my pace for 3K, which is the V02Max pace (by one of many accepted notions), gives me 710 seconds for 3k which implies 23.67 seconds per 100m. At 170%, I'd need to cover 170m in 23.67s. For 20s (as per the protocol), I need to cover 143m and from online maps, it looks like I'm covering around 140m. The fuzzy logic comes in because I'm doing the Tabata cycles on grass whereas the 5:55 min/mile pace that I used to calculate my V02Max was done on tar, concrete, and dirt. Add to that the fact that I'm using online maps to measure my runs. So, fuzzy gets a bit fuzzier.
Nonetheless, the workout itself is a killer. I can barely finish 4 cycles of the protocol whereas it calls for up to 8 cycles. My RHR these days is around 42-45 but even after 2+ hours of finishing one of these workouts, I'm still ticking away at 70+ beat/minute.