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  5. Shoulders
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  7. Plyo Jacks

Exercise guide

Plyo Jacks

  • Intermediate
  • Compound
  • Timed hold
  • Shoulders

Plyo Jacks are an explosive, high-intensity variation of the jumping jack that integrates a full squat to maximize lower-body power and metabolic demand. This compound movement builds explosive strength in the glutes and quads while challenging the core and shoulders for stability.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Plyo Jacks demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Calves
  • Glutes
  • Quadriceps

Secondary

  • Serratus anterior

Equipment

  • Body weight

Setup

  1. Stand with your feet together and arms resting at your sides.
  2. Engage your core and maintain a neutral spine with your gaze forward.
  3. Keep a slight, athletic bend in your knees to prepare for the jump.

How to do it

  1. Jump your feet out wide while simultaneously sinking your hips back and down into a deep squat.
  2. Swing your arms out and up toward the ceiling as you descend, keeping your chest lifted.
  3. Explosively drive through your heels to jump back to the starting position, bringing feet together and arms to sides.
  4. Inhale as you drop into the squat; exhale forcefully as you power back to the standing position.

Form checklist

  • Keep your knees tracking over your toes, preventing them from caving inward.
  • Land softly on the mid-foot to absorb impact before sitting back into the heels.
  • Maintain a flat back and avoid rounding your shoulders as you squat.
  • Ensure your hips drop as deep as your mobility allows to maximize glute engagement.

Pro tips

  • To increase pectoral and deltoid engagement, focus on a wide, controlled arc with the arms rather than just swinging them.
  • Focus on a rapid 'rebound' effect; spend as little time as possible in the standing position to keep the heart rate elevated and tension on the muscles.

Make it harder

  • Add a floor touch with both hands at the bottom of each rep to ensure consistent depth and increase the range of motion.
  • Wear a weighted vest to increase the load on the quadriceps and calves during the explosive jump phase.

Frequently asked

What muscles does the plyo jacks work?
The plyo jacks primarily targets the calves, glutes, and quadriceps, and also works the serratus anterior as secondary muscles.
What equipment do you need for the plyo jacks?
The plyo jacks requires no equipment — just your body weight.
Is the plyo jacks good for beginners?
The plyo jacks is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Arm Circle StepbackIntermediate · calves, glutes, hamstrings, and quadriceps
  • Barbell Clean High PullAdvanced · calves, glutes, hamstrings, quadriceps, and trapezius
  • Barbell Clean PullAdvanced · calves, glutes, hamstrings, quadriceps, and trapezius
  • Barbell Deadlift 360 DegreesIntermediate · calves, glutes, hamstrings, quadriceps, 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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