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  3. Exercises
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  5. Chest
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  7. Plank Arm Reach

Exercise guide

Plank Arm Reach

  • Intermediate
  • Compound
  • Timed hold
  • Chest
  • Lower arms
  • Shoulders
  • Upper arms
  • Waist

The Plank Arm Reach is a dynamic core stability exercise that challenges anti-rotation while engaging the shoulders and glutes. It builds functional strength by forcing the core to stabilize the torso as the center of gravity shifts during the unilateral reach.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Plank Arm Reach demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Obliques
  • Trapezius

Secondary

  • Biceps
  • Forearms
  • Serratus anterior
  • Triceps

Equipment

  • Body weight

Setup

  1. Start in a high plank position with your hands directly under your shoulders and arms fully extended.
  2. Position your feet slightly wider than hip-width to create a stable base for your pelvis.
  3. Engage your glutes and pull your belly button toward your spine to create a straight line from head to heels.

How to do it

  1. Exhale as you slowly reach one arm straight forward until it is parallel to the floor, keeping your thumb pointing up.
  2. Hold the reach for one second, focusing on keeping your hips perfectly level and square to the ground.
  3. Inhale as you lower the hand back to the starting position with control, avoiding any shifting in your torso.
  4. Repeat the movement with the opposite arm and continue alternating sides at a slow, controlled tempo.

Form checklist

  • Keep hips square to the floor; do not let them tilt or rotate as you reach.
  • Maintain a neutral spine and avoid letting your lower back sag toward the floor.
  • Keep the neck long and gaze slightly ahead of your hands to avoid neck strain.
  • Push actively through the grounded hand to keep the supporting shoulder stable and engaged.

Pro tips

  • Imagine a glass of water sitting on your lower back; your goal is to reach without spilling a single drop.
  • Squeeze your glutes as hard as possible during the reach to lock your pelvis in place and prevent hip sway.
  • Focus on 'pushing' the floor away with your stationary hand to maximize serratus anterior and deltoid activation.

Make it harder

  • Narrow your foot stance to decrease your base of support and significantly increase the anti-rotational demand.
  • Perform the reach while holding a light dumbbell or wearing wrist weights to increase the load on the shoulders and core.

Frequently asked

What muscles does the plank arm reach work?
The plank arm reach primarily targets the abs, obliques, and trapezius, and also works the biceps, forearms, serratus anterior, and triceps as secondary muscles.
What equipment do you need for the plank arm reach?
The plank arm reach requires no equipment — just your body weight.
Is the plank arm reach good for beginners?
The plank arm reach is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Crocodile CrawlAdvanced · abs, hamstrings, obliques, pectorals, and trapezius
  • InchwormIntermediate · abs, hamstrings, obliques, pectorals, and trapezius
  • Kneeling Plank Alternating Arm RaiseIntermediate · abs, obliques, and trapezius
  • Parsva Balasana Yoga PoseBeginner · abs, erector spinae, lats, obliques, pectorals, and trapezius

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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