In-In-Out-Out
In-in-out-out is a fast-feet cardio drill: both feet step narrow, then wide, in a drumming one-two rhythm that lifts the heart rate without a single jump. It suits warm-ups and low-impact conditioning blocks — jack-style work for anyone who wants to spare the joints. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.
Muscles worked
Sets & reps by goal
| Goal | Sets × Reps | Rest |
|---|---|---|
| Strength | 6 × 15 s max-speed intervals | 45 s |
| Muscle | 5 × 30 s brisk intervals | 30 s |
| Endurance | 3 × 60–90 s steady | 30–45 s |
Rep ranges per Helms 2014 · Schoenfeld 2016.
Level — Beginner
Beginner — coordination arrives within a session or two; then speed becomes the challenge.
Proper form — 5 cues
- Start with feet wide, knees soft, weight on the balls of the feet.
- Step right in, left in, right out, left out — hold that one-two-one-two drumbeat.
- Stay in a quarter-squat the whole time; head height should barely change.
- Pump the arms in rhythm to drive tempo and balance.
- Swap the leading foot halfway through each interval so both sides share the work.
Breathing: Breathe freely and rhythmically; if you cannot, the interval is longer than your current pace deserves.
The 3 mistakes Maddy corrects most
How to program in-in-out-out
| Goal | Phase | Sets | Reps | Tempo | Rest | RPE |
|---|---|---|---|---|---|---|
| strength | weeks 1–4 · build | 6 | 15 s intervals | max speed | 45 s | 7 |
| strength | weeks 5–8 · intensify | 6 | 15 s intervals | max speed | 45 s | 8 |
| strength | weeks 9–12 · peak | 6 | 15 s intervals | max speed · taller posture | 45 s | 9 |
| hypertrophy | weeks 1–4 · build | 5 | 30 s intervals | brisk | 30 s | 7 |
| hypertrophy | weeks 5–8 · intensify | 5 | 30 s intervals | brisk | 30 s | 8 |
| hypertrophy | weeks 9–12 · peak | 5 | 30 s intervals | brisk · tighter rhythm | 30 s | 8–9 |
| endurance | weeks 1–4 · build | 3 | 60 s steady | steady | 30–45 s | 6 |
| endurance | weeks 5–8 · intensify | 3 | 75 s steady | steady | 30–45 s | 7 |
| endurance | weeks 9–12 · peak | 3 | 90 s steady | steady | 30–45 s | 7–8 |
| beginner | weeks 1–4 · learn | 3 | 20 s easy rhythm | easy · learn the pattern | 45–60 s | 5 |
| beginner | weeks 5–8 · groove | 4 | 25 s easy rhythm | easy · add arm swing | 45–60 s | 6 |
| beginner | weeks 9–12 · load | 4 | 30 s brisk | brisk · quiet feet | 45–60 s | 6–7 |
Tempo = descriptive — continuous footwork drill, pace named per row.
Common questions
Is in-in-out-out low impact?
Yes — that is its main selling point. Both feet step rather than jump, so ground contact stays gentle while the tempo does the conditioning work. It is a sensible swap for jumping jacks when knees, shins, or downstairs neighbours object to repeated landings.
How fast should I go?
Fast enough that holding a conversation would be annoying, controlled enough that the rhythm never breaks. Speed is the progression lever here: master a clean 30-second pattern at moderate pace first, then chase quicker feet in short intervals rather than long sloppy ones.
In-in-out-out vs jumping jacks — which burns more?
Jumping jacks generally demand more per second because of the airborne phase, but the honest answer is that intensity and duration matter more than the drill you pick. Choose the one you can push harder and repeat more often without joint complaints; for many people that is this one.
How do I fit in-in-out-out into a HIIT circuit at home?
Use it as the pulse-raiser between strength stations rather than as a station you grind. A simple structure: squat variation, push-up variation, then fifteen to thirty seconds of in-in-out-out before resting, repeated for four to six rounds. Because it is low impact and needs no space, it keeps the heart rate elevated without frying your legs for the next strength move. If it is your finisher instead, run six max-speed fifteen-second bursts with forty-five seconds of rest.
Will in-in-out-out improve my footwork for sports?
It helps in the way ladder drills help: faster, more rhythmic ground contacts and better coordination between feet and arms. The narrow-narrow-wide-wide pattern trains the calves and hips to redirect quickly, which shows up in sports that punish slow feet — badminton, tennis, football. What it will not do is replace sport-specific practice, because real games demand reactions to an opponent, not a fixed rhythm. Treat it as a warm-up and general quickness drill, and it earns its place.
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