A Tabata workout is a four-minute high-intensity interval routine: 20 seconds of near-all-out effort followed by 10 seconds of rest, repeated for about eight rounds. It is named after Japanese researcher Izumi Tabata, whose 1996 study had subjects pedal a cycle ergometer at roughly 170% of their VO2max for seven to eight 20-second bouts with 10-second rests, five days a week for six weeks. That protocol raised VO2max by about 7 ml/kg/min and anaerobic capacity by 28%, while an hour of moderate cycling at 70% of VO2max improved VO2max but not anaerobic capacity. Many classes now apply the same 20/10 timing to bodyweight moves such as burpees or squat jumps, but the original method depends on an intensity hard enough to exhaust you by the seventh or eighth round.
Image: Indoor cycling at a U.S. Army fitness center, 2014 (U.S. Army photo, public domain), via Wikimedia Commons.