15 minute AMRAP
The Engine Block
Cardio capacity · Engine Room · intensity 3 of 5
The workout
As many rounds as possible in 15 minutes of:
Overview
The Engine Block is 12 down-ups, 24 alternating lunges, and 30 jumping jacks. The work moves through the full body and the quads instead of sitting on one muscle.
Muscles worked
Full body
Glutes
Quads
Energy systems
These are overlapping contributions. This workout is not assigned to one energy system.
- Glycolytic: Low
- Oxidative: High
- Neuromuscular: Low
Training effect
Immediate demand
15 minutes, intensity 3 of 5. Today the limiter is the jumping jacks.
Intended stimulus
The same capacity work, with movements you can repeat for the whole clock. On this workout that is 12 down-ups, 24 alternating lunges, and 30 jumping jacks.
Repeated practice
Repeat the same workout and compare the score. What can change over weeks is how long that pace lasts. One time through does not produce that change.
Body-composition context
Body weight changes with the rest of how you eat and train. This workout is one piece of work on one day.
Expected feel
30 jumping jacks is where the round gets hard. The other movements still have to be finished after it.
Pacing
The ultimate test of consistency. If your round times vary by more than 10 seconds, you are failing the pace.
Keep the later rounds moving at the same size as the early ones. Do not drop the jumping jacks to keep the other sets moving.
The movements
Down-Ups
This movement is all about hip-hinge efficiency. Minimize the time spent with your hands on the floor.
What not to do. Popping the chest up before the hips, so the body peels off the floor in sections.
Alternating Lunges
Reverse lunges are superior for AMRAPs. They protect the deceleration forces on the knee and allow for a faster, springier return to the standing position.
What not to do. Letting the front knee travel past the toes as the torso pitches forward.
Jumping Jacks
Use this movement for active recovery. When paired with burpees or mountain climbers, the jumping jack is your opportunity to catch your breath.
What not to do. Bending the elbows so the hands never meet overhead.
Why these movements
The work moves through the full body and the quads instead of sitting on one muscle.
Scaling
Keep the round short enough to repeat. Drop reps so you can stay moving, rather than resting the round into a different workout.
Down-Ups
- Step the feet. Step back and step in instead of jumping. Same shape, no impact.
- Hands elevated. Hands on a bench or step so the floor never comes all the way up to you.
- No jump at the top. Stand tall and reach instead of leaving the floor.
Alternating Lunges
- Hold a support. One hand on a wall or chair for balance. The legs still do the work.
- Shorter range. Drop only as far as you can stand back up from without pushing off your hands.
Jumping Jacks
- Low impact. Keep one foot down throughout — march the pattern instead of running it.
- Slower cadence. Same movement, fewer beats per minute. Cadence is the dial, not the shape.
Mistakes and who it is for
- Opening the down-ups at a sprint makes the jumping jacks the piece that falls apart.
- Resting until you feel fresh between movements removes the point of keeping them in one round.
- Spending the first minutes hard leaves the later rounds as a different, slower workout.
Suited to someone who wants 15 minutes through Down-Ups, Alternating Lunges, Jumping Jacks.
Scoring and progression
Work through the movements in the order listed, then start the next round. Your score is the number of complete rounds plus any reps of the round you were partway through when the clock hit zero — written as rounds plus reps, so seven full rounds and twelve reps is7+12.
Progression is repeating this workout and comparing that score. The page does not promise a change from one time through.
Related workouts
- Posterior Vanguard
Same quads, longer clock
- The Cruiser
Same quads, shorter clock
- The Endurance Engine
Same quads, longer clock
Run it with friends
The Engine Block runs on a shared countdown: share a rally link, everyone gets the same 15-minute clock, and the leaderboard updates as people log rounds.