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  5. Shoulders
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  7. Knee Raise Side Jab

Exercise guide

Knee Raise Side Jab

  • Intermediate
  • Compound
  • Rep-based
  • Lower arms
  • Shoulders
  • Upper arms
  • Waist

This dynamic compound movement combines a high knee drive with a cross-body punch to engage the core and obliques while building upper body coordination and cardiovascular endurance.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Knee Raise Side Jab demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Deltoids
  • Obliques

Secondary

  • Hip flexors
  • Quadriceps
  • Serratus anterior

Equipment

  • Body weight

Setup

  1. Stand with your feet hip-width apart and a slight bend in your knees.
  2. Bring both hands up to a 'guard' position near your chin with elbows tucked close to your ribs.
  3. Engage your core and maintain an upright posture with your shoulders pulled back.

How to do it

  1. Simultaneously drive your right knee up toward your chest while extending your left arm in a controlled jab across your body to the right.
  2. Exhale sharply at the peak of the movement, focusing on the contraction in your obliques and abs.
  3. Return your foot to the floor and snap your hand back to the guard position with control.
  4. Repeat the movement on the opposite side, alternating sides for each repetition at a steady, rhythmic tempo.

Form checklist

  • Keep your standing leg slightly bent to maintain balance and absorb impact.
  • Avoid leaning backward as you lift your knee; keep your torso as vertical as possible.
  • Ensure your punching arm does not fully lock out at the elbow to protect the joint.
  • Pivot slightly on the ball of your standing foot to allow for a natural hip rotation during the jab.

Pro tips

  • Visualize 'crunching' your ribs toward your opposite hip during the knee raise to maximize oblique activation.
  • Focus on the 'snap' of the punch—retracting the arm quickly is just as important for muscle engagement as the extension.

Make it harder

  • Increase the speed of the transitions to turn the exercise into a high-intensity cardio interval.
  • Hold light dumbbells or wear weighted wrist bands to increase the resistance on the deltoids and pectorals.

Frequently asked

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

Related exercises

  • 45 Degrees Arms PlankIntermediate · abs, deltoids, obliques, and pectorals
  • Bear WalkIntermediate · abs, calves, deltoids, hamstrings, obliques, and pectorals
  • Bosu Ball Plank HoldIntermediate · abs, deltoids, obliques, and pectorals
  • Decline Shoulder TapIntermediate · abs, deltoids, and obliques

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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