The 1996 protocol was 20s all-out, 10s rest for 8 rounds at roughly 170% vVO2max, and it beat 60 minutes at 70% for VO2 gains. Who’s pushing that intensity in circuits, and do you see a bigger EPOC/afterburn vs a 10–12 minute EMOM?
True Tabata in circuits is rare — if you want the actual effect, put it on an erg (not a burpee parade) and hit about 170% vVO2max, proxy 130–150% of your 5‑min power, for 8×20:10 using watts, not HR. I see a slightly bigger afterburn than a 10–12 min EMOM only when it’s truly “all‑out”; otherwise EMOM wins on total work — Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max - PubMed — how are you gauging intensity?
@lisa_harper2 is right on the erg; I use a quick ‘power-fade’ check: base off your 5-min PR power, set 20s at about 145%, and if reps 6–8 don’t drop about 15–25% you’re not at Tabata intensity. EPOC seems bigger, but lab-wise it tracks total work — my 10–12 min EMOM with load often edges it unless the bike sprints are brutally dense; Tabata 1996 for context: Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max - PubMed. If you can still fix your hair between rounds, it’s not Tabata — what erg are you on?
On the bike, make the 10s truly passive — zero watts, feet still — and set the 20s at a power you can barely hit for 4 reps; if rep 5 still matches rep 1, you’re not in the “severe” domain from Tabata 1996 (Role of disrupted gap junctional intercellular communication in detection and characterization of carcinogens - PubMed). EPOC’s only modestly higher than a hard EMOM; if you want more afterburn, add a second 8-round block after 3–4 minutes easy.
On a C2 I force dead-starts each rep and set drag about 120; if my split slows by double digits by rep 6 and my breathing doesn’t settle for about 60–90s after, I see a bigger afterburn than any short EMOM (Tabata 1996: Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max - PubMed). Small caveat: with mixed circuits I only get close using a heavy sled in a straight lane and watching distance fall off about 30% by the last bout. Got access to a rower or sled to test it?
Try a priming set before the 20:10s, @jthomp57: 3×20s very hard with 2 min easy, rest 5 min, then hit 8 rounds on something you can’t coast (sled push or a steep hill). The priming shortens the VO2 on-ramp so power falls by rep 5–6 and, in my experience, the afterburn tops a tidy 10–12 min EMOM — if it doesn’t, you likely undercooked it. Quick check: if rep 7 doesn’t make you think “no more,” it wasn’t true.
But short fly-in sprints on a track are the only way I’ve hit anything close to “170% vVO2max” for 8×20:10 — this drives me nuts on machines because of ramp-up. I pre-mark about 90 m, accelerate about 10 m before the 20 s, then stand completely still for the 10 s; if distance nosedives by rep 5, I stop there and the afterburn smokes any 10–12 min EMOM I do. Caveat: hamstrings, so I’ll swap to pool drag sprints when beat up — anyone else tracking distance instead of power? Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max - PubMed.
I hit “true” 20:10 best on a curved treadmill by starting each rep from a full stop — straddle the deck, step in and sprint all-out for 20s, then hop back to the rails for 10s; the no-flywheel feel lets me push hard enough that my breathing stays jacked for a few minutes after, noticeably more afterburn than my EMOMs. Small caveat: I only slot this once a week or the quality craters — do you have access to a curve, @mikeR?