10 minute AMRAP
The Iron Cross
Core under fatigue · Midline Tension · intensity 3 of 5
The workout
As many rounds as possible in 10 minutes of:
Overview
The Iron Cross is 12 plank knee-to-elbows, 15 air squats, and 20 jumping jacks. The work moves through the midline, the quads, and the full body instead of sitting on one muscle.
Muscles worked
Full body
Midline
Quads
Energy systems
These are overlapping contributions. This workout is not assigned to one energy system.
- Glycolytic: Moderate
- Oxidative: Moderate
- Neuromuscular: Moderate
Training effect
Immediate demand
10 minutes, intensity 3 of 5. Today the limiter is the jumping jacks.
Intended stimulus
The style is built so a trunk position has to survive the moving reps. On this workout that is 12 plank knee-to-elbows, 15 air squats, and 20 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
20 jumping jacks is where the round gets hard. The other movements still have to be finished after it.
Pacing
Squeeze the obliques deliberately on the plank; use the squats to recover your breath.
Keep each round about the same length. Do not drop the jumping jacks to keep the other sets moving.
The movements
Plank Knee-to-Elbows
Keep hips completely level to avoid shifting the workload to the hip flexors.
What not to do. Dropping the hip toward the floor to help the knee travel.
Air Squats
Let gravity do the work on the way down. Pull yourself into the bottom quickly, then explode up. Use your arms for rhythm.
What not to do. Cutting the depth once the legs burn, so the hip crease stops above the knee.
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 midline, the quads, and the full body instead of sitting on one muscle.
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.
Plank Knee-to-Elbows
- From the knees. Knees down, straight line from knees to shoulders.
- Hands elevated. Hands on a bench or step. The higher the surface, the less you carry.
Air Squats
- To a seat. Squat to a chair or box and stand back up. Lower the seat as you improve.
- Hold a support. Hands on a doorframe or chair back to sit deeper than balance allows alone.
- Shorter range. Go only as deep as you can control, and stop before the heels lift.
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 plank knee-to-elbows 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.
- Letting the jumping jacks shrink so the rest of the round can speed up changes the workout on the page.
Suited to someone who wants 10 minutes through Plank Knee-to-Elbows, Air Squats, 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
- Iron Spine
Same midline and quads, longer clock
- Static Equilibrium
Same midline and quads, longer clock
- The Brace
Same midline and quads, longer clock
Track every round. Sync with friends when you want to.
The Iron Cross is a 10-minute clock with rounds and splits for you. Share a rally link when other people join, and the leaderboard updates as they log rounds.