Grindstone is a dumbbell workout in the straight-sets tradition - no circuit here. Six exercises, each done for 5 full sets with 30 seconds of rest between sets before moving on: 12 split lunges, 12 calf raises, 12 kneeling rows, 12 bent over bicep curls, 6 crunch folds and 6 sitting twists. One exercise at a time, ground down completely, then the next.

The name is the method. Straight sets with short rests are the grindstone of strength training - the same movement pressed against the same muscles five times in a row, with 30 seconds being just enough recovery to go again and nowhere near enough to feel fresh. By the fourth and fifth sets of any exercise here, the reps are earned rather than performed, and that accumulated, slightly-under-recovered volume is precisely the stimulus this format exists to deliver. The exercise order runs the body top to bottom in pairs: split lunges and calf raises grind the legs, kneeling rows and bent over curls grind the pulling muscles from two hinged positions, and the weighted crunch folds and sitting twists finish on the core, where 6 reps with a dumbbell in hand outwork 20 without one. Nothing clever, nothing flashy - an edge is not sharpened by novelty.

Keep split lunges in a fixed stance, dropping the back knee straight down with the dumbbells hanging quiet. Rise fully on every calf raise with a pause at the top. In kneeling rows, brace on the forward thigh and pull the dumbbell to your hip with a flat back; in bent over curls, hinge and let the arms hang before curling with pinned elbows. Crunch folds bring knees and dumbbell together over your middle with control, and sitting twists rotate from the trunk, weight travelling side to side while your heels hold their ground.

Five sets against the stone, six times over. That is how edges happen.

Make it Harder: Trim every rest to 20 seconds and keep all 5 sets.

Make it Easier: Drop to 3 sets per exercise with the full 30 seconds between them.