Every session Tuin will ever give you.

The bread and butter.

Most of your week. Builds the aerobic engine — more capillaries, more mitochondria, a stronger heart — at a cost your legs can pay every day. There is no structure because structure would only tempt you to push.

Blood flow to tired legs, nothing more.

The day after a hard one. Short, flat, and slow enough to feel silly. It exists to help you absorb yesterday's work, not to add to it — walk breaks are fine.

The weekly anchor.

Endurance, fuel economy and mental callus, built over months. Early in a cycle it stays entirely easy and grows a little each week, with a cutback every third or fourth. Fuelling is rehearsed here — eat something every 40–45 minutes past the 90-minute mark.

The cheapest speed you will ever buy.

An easy run that ends with a handful of 20-second accelerations, fast and relaxed, with a full walk-back between them. They teach your legs to turn over quickly without any real fatigue — one or two times a week is the best economy gain per minute in running.

Not a run — the thing that keeps you running.

Twice a week, heavy and low-rep: squat or hinge, calf raises straight- and bent-knee, single-leg hip work. It roughly halves overuse injuries, and it gets its own dated session in your plan — never folded into a run, never counted as training load.

Where the training actually happens.

A day off is a training decision, not a gap. Fitness is built in the recovery between sessions; a plan that fills every day is asking your body to adapt without giving it the time to. Tuin leaves days deliberately open.

Each block a notch faster, finishing near 10K pace.

A continuous run split into blocks, each one faster than the last: easy, steady, threshold, then a short push near 10K pace. Renato Canova's fingerprint. It teaches you to speed up on tiring legs — the exact skill a well-run race needs — and it gets a lot of quality into one session without the damage of starting hard.

Alternate just above and just below threshold, without stopping.

Blocks that alternate a pace a touch slower than threshold with a pace a touch faster — and the 'under' is the recovery, so you never stop. Borrowed from cycling, where it is a staple. It trains your body to clear lactate while still running hard, which is what a surge on a hill or a mid-race move actually demands. The more race-specific cousin of the plain tempo.

Shorter and faster each rung, with a real rest between.

Three kilometres near half-marathon pace, two near threshold, one near 10K pace, each followed by a walking rest that shrinks as the reps do. A descending ladder puts the fastest running last, on legs that are already tired — and the shrinking distance makes each rung feel achievable. A big dose of threshold work that never feels like a wall.

One block, comfortably hard, held.

The original. Twenty to forty minutes at or just under threshold — your one-hour race effort — in one continuous block. Raises the pace you can hold before lactate starts to pile up, which is the number that decides every race from 10K to the marathon. It grows across a cycle: 20 minutes early, 40 or more late.

Threshold pace, broken into pieces with short rests.

Jack Daniels' idea: the same threshold pace as a tempo, but in repeats of a mile or so with only a minute between. The short rest lets you bank more total time at threshold than one block could — 25–30 minutes instead of 20 — with the pace held cleaner throughout. The Norwegians built a whole system on this.

Between easy and marathon pace — the forgotten gear.

A run held at a moderate, honest pace — quicker than easy, slower than marathon pace — for 40 to 70 minutes. Lydiard's bread and butter. It builds aerobic strength without the recovery cost of true quality, and it is the gear you will actually use for most of a marathon.

Three to five minutes hard, jog, repeat.

Repeats of 800 to 1600 metres around 5K pace, with a jog recovery about as long as the rep. The sharpest tool for raising your ceiling — the maximum rate your body can use oxygen — and the anchor session of any 5K or 10K build. Dosed small: the hard running adds up to no more than about 8% of the week.

One minute on, one minute floating. Twenty times.

Short hard efforts — 30 seconds to a minute at 5K pace — with 'floats' between them: you ease off, but you keep running. Because the offs are short and not slow, your oxygen uptake stays high the whole time, so you get a big aerobic stimulus with far less strain than long reps. Véronique Billat's 30/30 is the classic; the Norwegians run 45/15 up hills.

Speed play, by time and by feel.

Swedish for 'speed play': surges of one to three minutes inside an otherwise easy run, recovered by feel rather than by the watch. It brings quality without the pressure of a pace target, which makes it the right hard day when you are tired, when the ground is rough, or early in a cycle when the legs are not ready for the track.

A big block at race pace, in the middle of a long run.

The most specific session in a half or marathon build: an easy lead-in, then a long block at goal race pace on legs that already carry some fatigue, then an easy finish. Pfitzinger's marathon-pace long runs are the model. It rehearses the pace, the fuelling, the shoes and the head all at once — and it grows across the cycle, 6 km at pace early, 16–19 km at pace late. Never more than two or three in a block.

Easy for most of it, then the last quarter at marathon pace.

A long run that finishes strong: the last 5–8 km at marathon pace, on legs that have already done the distance. It trains the exact moment a marathon is won or lost — holding pace late — and it teaches you to run fast on empty. Two to four per cycle, the first 8–10 weeks out, the last at least three weeks before race day. A 'thirds' version (easy, steady, marathon-ish) is the gentler entry to it.

30–90 seconds steep and strong, walk down, repeat.

Near-maximal efforts up an 8–12% grade, walked back down with full recovery. Strength and power with almost no impact — the hill takes the landing forces the track would put through your shins. The first speed work in any trail plan, and a fine one for road runners too.

3–5 minutes up a runnable climb, jog down.

The trail runner's VO2 session: repeats of three to five minutes up a 5–7% grade at a hard, rhythmic effort, jogged back down. It builds climbing-specific strength and top-end fitness in one, with the grade keeping your speed — and your impact — honest.

20–30 minutes of sustained climbing at threshold effort.

The tempo run, moved onto a climb. One long block of steady uphill at comfortably-hard effort, with heart rate as the ceiling — pace means nothing here. It is the closest thing to what a mountain race actually asks of you: a long, hard, sustained climb with no rest.

Descending is a skill — and a muscle — you have to train.

Controlled descents of two to four minutes, hiked back up. The point is the eccentric load — your quads braking on every step — which is what actually ends trail races, not cardio. Two or three of these, landing three to five weeks before race day, protect your legs for six to nine weeks. Never in race week.

Power-hike the steep, run the runnable, at race effort.

Over/unders for the mountains. Blocks that alternate hard power-hiking on steep ground with running on the runnable grade, continuously, at the effort you plan to race at. Power-hiking above about 15% is faster and cheaper than running, and it is a skill: this session is where you learn to switch between the two without losing rhythm — the thing a hilly race asks of you a hundred times.

Let the trail set the intervals.

A fartlek where the ground decides: surge on every climb, float over the top, relax the descents, for 40 minutes on a rolling loop. No watch targets at all. It teaches you to read terrain and to spend effort where it buys the most — on the ups — which is the whole art of racing hilly trails.

Hours and metres of climb, not kilometres.

Planned by time on feet and vertical gain, because on trail distance is the least reliable number there is. Easy effort throughout, hiking the steep bits, fuelling from the first hour — every long run is a rehearsal of race-day eating. It grows toward 60–70% of the race's climb and caps at four to five hours; beyond that it costs more than it gives, whatever the race distance.

A taste of race pace, four or five days out.

One short session at goal race pace, in a shape you have already run this block, with the work volume cut by half to two thirds. It keeps your legs sharp through the taper — cutting intensity is what causes flat, heavy race-day legs — and rehearses the pace one last time. It builds nothing; it is not a fitness test. On trail it goes uphill only.

The day before: short, easy, with a few strides at race pace.

Fifteen to twenty-five minutes easy, ending with four to six strides of 20–30 seconds at race pace, full recovery between. Wakes the nervous system up, shakes out travel stiffness, and reminds your legs what tomorrow feels like — without touching your glycogen. Even a 100-miler gets these.

Even splits. Never bank time.

The session everything else was for. A full warm-up with strides for a 5K or 10K, a minimal one for a marathon. Then the plan: even or slightly negative splits, fuel on the schedule you rehearsed, and the first kilometre slower than feels right — every well-run race in history started that way.