CalisthenicsIn review

Plank Jack

A straight-arm plank with small jumps that move both feet out and in.

This page is a working draft. A coach has not reviewed it, so read it as a starting point, not as checked instruction.

Pattern: Trunk stability
Modality: Calisthenics
Difficulty: Beginner
Mechanic: Unknown
Force: Unknown
Laterality: Bilateral
Impact: Moderate
Trains where: Gym, Home
At home: Yes

How to do it

Set up

Start in a straight-arm plank with the hands under the shoulders and the feet together.

Do the rep

Brace the trunk and jump both feet apart.
Jump both feet back together and land softly without dropping the hips.

What counts as a rep

One rep moves both feet apart and back together while the trunk stays steady.

Breathing

Exhale through the effort and inhale during the controlled return.

Cues

Keep the hips level.
Land softly.

Common mistakes

Dropping the hips
What you seeThe lower back arches as the feet land.
FixUse smaller jumps and end the set if the trunk moves.
A steady trunk keeps the movement controlled.

Stop the set if

Stop if you feel sharp pain.
End the set if you cannot land softly or hold the plank.

General educational content, not individual coaching or medical advice.

Muscles worked

Prime movers

Rectus abdominis · moderate confidence
Obliques · moderate confidence
Deep core / trunk stabilizers · moderate confidence

Assisting

Hip flexors · moderate confidence
Shoulders (coarse UI group) · moderate confidence
Forearms and grip · moderate confidence

Equipment

Bodyweight

Optional: Floor mat

Start in a straight-arm plank with the hands under the shoulders and the feet together.

In the app

You log this by hand. The camera coach does not watch this movement yet.

Tracking: Manual

How this page was checked

Draft. A editorial reviewer has not signed this off yet.

Draft text is original copy for Wave 2 batch 6, written from the blueprint CSV row and the owner rules approved 2026-10-12 in #340. No human review is complete.
Technique, cues, rep standard, breathing, stop cues, and error corrections need independent sources and the assigned review tier (blueprint two-source rule).
Programming roles, skill tier, failure cost, timed use, goal fit, and equipment remain candidates; the switch-on PR must confirm them.
Anatomy uses the CSV planning hints; the assigned review tier must confirm it.
Legacy relations and engine edges stay empty until the progression ladder lane and S2-CAT-005.
Timed use and goal fit copy ex_mountain_climber, the closest Wave 1 record. Its review evidence does not approve this draft.
Rule 2 gives every bodyweight and band core row the trunk role.
Rule 1 removes the CSV optional pull-up-bar from this floor row; floor-mat stays optional.
Bodyweight-reps only replaces the CSV reps-or-duration. No kg are logged. The draft counts full movement cycles rather than hold time.
Skill tier beginner: a new user can perform one clean rep or brief hold in the first session. Failure cost low: the user can stop on the floor or release band tension safely (rule 3).
The CSV impact is low. Small jumps make this moderate impact; the review must confirm the impact rating.

All instruction and editorial text in this record is original draft copy written for Allena. Planning metadata comes from the internal Wave-2 blueprint CSV.

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