Tabata

Tabata is twenty seconds of hard work followed by ten seconds of rest, repeated eight times. That comes to four minutes per exercise. The protocol came out of 1990s interval research on trained cyclists, and done properly it is much harder than its reputation as a quick workout suggests.

Ten seconds is not long enough to recover, so your choice of exercise decides everything. Good Tabata exercises are simple, repetitive and safe to do while tired. Squats, mountain climbers, kettlebell swings and jumping jacks all qualify. Complicated or heavily loaded lifts do not, because your form falls apart at exactly the moment the clock tells you to keep going. The generator only picks exercises marked as safe for timed work at high fatigue.

A full session stacks three to five of these four-minute blocks with a minute of recovery between them, mixing lower-body, whole-body and core movements so the fatigue spreads out instead of landing in one place.

Go slightly below your maximum for the first two rounds. From round five onward the format punishes anyone who started too fast, and the aim is eight consistent rounds rather than two heroic ones.