5 minute AMRAP
The Arch
Core under fatigue · Midline Tension · intensity 3 of 5
The workout
As many rounds as possible in 5 minutes of:
Overview
The Arch is a 15-second hollow hold and 16 alternating bird-dogs. Every piece stays on the midline. Later rounds slow because the work never leaves the midline.
Muscles worked
Midline
Energy systems
These are overlapping contributions. This workout is not assigned to one energy system.
This workout departs from its style on the profile below.
- Glycolytic: Moderate
- Oxidative: Moderate
- Neuromuscular: High
Training effect
Immediate demand
5 minutes, intensity 3 of 5. Today the limiter is the hollow hold before the alternating bird-dogs.
Intended stimulus
The style is built so a trunk position has to survive the moving reps. On this workout that is a 15-second hollow hold and 16 alternating bird-dogs.
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
The hold is the start of the round. The next movement still has to be done after it, not as a rest earned by the hold.
Pacing
Anterior hollow into posterior reach. Crush the lower back into the floor on the hollow; keep the hips level on the bird-dogs.
Do not shorten the hollow hold to reach the alternating bird-dogs. The hold is the start of the round. The next movement still has to be done after it.
The movements
Hollow Hold
Fatigue causes the back to arch. Regress the movement immediately by tucking your knees toward your chest when this happens.
What not to do. Letting the lower back arch away from the floor as the legs tire.
Alternating Bird-Dogs
Reach long, not high. Hyperextending the back to get your leg higher defeats the core stabilization purpose entirely.
What not to do. Lifting the arm and leg above the line of the back, which arches the spine.
Why these movements
Every piece stays on the midline. Later rounds slow because the work never leaves the midline.
Scaling
Keep a brace or a hollow position in every round. Drop the moving reps before you drop the position that makes the trunk work.
Hollow Hold
- Knees bent. Bend the knees to shorten the lever. The shorter it is, the lighter it is.
- Partial range. Move only through the range where you can keep the lower back on the floor.
Alternating Bird-Dogs
- Shorter range. Lift only as high as you can hold the position without arching the back.
- Both legs. Drive through both feet instead of one.
Mistakes and who it is for
- Opening the hollow hold at a sprint makes the hollow hold the piece that falls apart.
- Resting the midline back to fresh between rounds turns this into a different workout.
- Letting the hollow hold shrink so the rest of the round can speed up changes the workout on the page.
Suited to someone who wants 5 minutes on the midline and can already do Hollow Hold, Alternating Bird-Dogs.
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
- Core Melt
Same hold, different moving piece
- Active Sonar
Same midline, longer clock
- Core Suspension
Same midline, longer clock
Run it with friends
The Arch runs on a shared countdown: share a rally link, everyone gets the same 5-minute clock, and the leaderboard updates as people log rounds.