Sep 19, 2026 · 6 min read
Interval training is a timing problem before it is a fitness problem. The exercises can be anything: sprints, burpees, kettlebell swings, a bike. What makes it interval training is the structure, a fixed span of work followed by a fixed span of rest, repeated. Get the structure right and the workout runs itself. Get it wrong and you spend the session watching a clock instead of moving.
This guide covers the three structures that account for most interval sessions, how to build each one as a cycle on radialtimers.com, and three ready-made sessions for when you have ten, twenty, or thirty minutes.
The name comes from Izumi Tabata, whose 1996 study used this exact split: 20 seconds of very hard work, 10 seconds of rest, eight rounds, four minutes in all. The protocol has since been applied to every exercise imaginable, but the timing is the whole point. Twenty seconds is short enough to go close to flat out; ten seconds is too short to recover, which is why the later rounds bite. Done as intended, one four minute block is a complete workout. Two or three blocks with a few minutes between them is a long one.
An EMOM is a series of one minute windows. At the top of each minute you do a set amount of work, say eight push-ups or five heavy swings, and whatever is left of the minute is your rest. Finish the work in twenty seconds and you rest forty; take fifty seconds and you rest ten. That self-adjusting rest is what makes EMOMs useful: the same session is gentle for a strong athlete and brutal for a beginner, and it teaches you to pace. Ten minutes is a common length. Twenty is a serious one.
A circuit moves you through several exercises in turn, each for a fixed work span with a fixed rest between. Common splits are 30 seconds on and 10 off for fast, light movements, 40 on and 20 off for controlled sets, and 45 on and 15 off when the stations are demanding. Five stations at 40/20 is a five minute round; three rounds is fifteen minutes of work. Circuits suit groups, garages, and anyone bored by doing one thing eight times.
On radialtimers.com a cycle is one timer that walks a list of blocks in order, chiming at every change, so you never have to watch for the switch. The home page ships with six cycles ready to run: pomodoro 25+5, pomodoro 50+10, HIIT 30/10, Tabata 20/10, intervals 45/15, and workout 40/20. Each also has its own page, so the Tabata timer or the HIIT timer is one click away.
To build your own, or to change a preset:
Edits to a preset are kept on your device and marked edited, with a reset that restores the shipped shape. Custom cycles stay in the list until you delete them.
So an EMOM is a cycle with one block, minute, set to 1:00, looped ten or twenty times. A five-station circuit at 40/20 is ten blocks in a row, named after the stations with a 20 second rest after each, looped three times. A Tabata with a longer break between blocks is work 20 s, rest 10 s, looped eight, run three times with a plain two minute timer between.
Intervals ask a lot of cold muscles, so the warm-up is not optional. Five minutes is enough for most sessions: two or three minutes of easy movement to raise your temperature, then a couple of rehearsal rounds of the exercises you are about to do at half effort. If the session is sprints or jumps, add a few short build-ups where you reach near full speed for a few seconds and ease off.
Run the warm-up on its own timer so it does not eat into the work. A five minute timer beside the cycle does the job, and since every timer on the site runs on its own, you can start the cycle the moment the warm-up chimes.
The cool-down is simpler: three to five minutes of walking or easy pedalling until your breathing settles, then whatever stretching you like. Time this too. Left untimed, most people skip it.
| Part | Timing | What to do |
|---|---|---|
| Warm-up | 3 min plain timer | Easy movement, then two rehearsal rounds. |
| Work | Tabata 20/10 ×8 | One exercise, or alternate two by round. |
| Cool-down | 3 min plain timer | Walk, breathe, stretch what is tight. |
The Tabata block is under four minutes, so the whole thing fits in ten. Go hard in the work; the rest is short by design.
| Part | Timing | What to do |
|---|---|---|
| Warm-up | 5 min plain timer | Raise the temperature, rehearse the moves. |
| Work | EMOM, 1 min ×12 | Alternate two exercises by minute; fixed reps each time. |
| Cool-down | 3 min plain timer | Easy pace until breathing settles. |
Pick a rep count you can finish in about forty seconds in the first minute. If you are finishing with less than fifteen seconds to spare by minute eight, the count is right.
| Part | Timing | What to do |
|---|---|---|
| Warm-up | 5 min plain timer | Include a few short build-ups. |
| Work | 5 stations at 40/20, looped 4 | Twenty minutes of circuit; change station at each chime. |
| Cool-down | 5 min plain timer | Walk, then stretch. |
Build the circuit as a cycle with ten blocks, five named stations each followed by a 20 second rest, looped four times with the final rest skipped. The strip on the card shows the blocks in proportion, so a glance tells you which round you are in, and the chimes carry you through with your back to the screen.
The chime is enough to keep the structure. Seeing the dial helps with pacing: in a 40 second block the rings empty every two seconds, so a glance halfway through tells you whether to push or hold back. For all-out Tabata rounds, ignore the screen and trust the sound.
Add a third block. A cycle of work 30 s, rest 10 s, work 30 s, rest 10 s, long rest 60 s looped five times gives you pairs of rounds with a minute between pairs. The blocks are just a list; there is nothing special about two.