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  7. Seated Alternate Leg Abduction And Extension

Exercise guide

Seated Alternate Leg Abduction And Extension

  • Beginner
  • Compound
  • Rep-based
  • Upper legs
  • Waist

This beginner-friendly seated exercise targets the lower abdominals and quadriceps through a combination of hip abduction and knee extension, enhancing core stability and leg definition.

Reviewed by the Crucible team · Updated June 2026

Watch the Seated Alternate Leg Abduction And Extension demonstrationGuided video and your full workout live in the Crucible app.

Muscles worked

Primary

  • Abs

Secondary

  • Glutes

Equipment

  • Body weight

Setup

  1. Sit on the edge of a sturdy chair or bench with your feet flat on the floor and knees bent at 90 degrees.
  2. Grip the sides of the seat firmly to stabilize your torso and lean back slightly while keeping your spine neutral.
  3. Engage your core by pulling your navel toward your spine to create a solid base.

How to do it

  1. Lift your right foot slightly off the floor, then simultaneously extend your knee and move your leg outward away from the midline.
  2. Exhale during the extension and abduction phase, squeezing your quadriceps and lower abs at the peak of the movement.
  3. Inhale as you reverse the motion, bringing the leg back to the center and returning your foot to the starting position.
  4. Repeat the entire sequence with the left leg, alternating sides with a controlled, 2-1-2 tempo (2 seconds out, 1 second hold, 2 seconds back).

Form checklist

  • Keep your chest lifted and avoid rounding your lower back as you lean.
  • Ensure the movement comes from the hip and knee, not by tilting your torso to the side.
  • Keep your toes pointed upward throughout the extension to maintain tension in the quadriceps.
  • Maintain a firm grip on the seat to prevent your hips from sliding forward.

Pro tips

  • Focus on the 'peak contraction' by holding the leg at full extension and maximum abduction for one second to maximize muscle fiber recruitment.
  • Keep your non-working leg pressed firmly into the floor to help stabilize your pelvis and isolate the core.

Make it harder

  • Perform the movement with your hands behind your head or reaching forward to remove the stability of the chair grip.
  • Add a light resistance band just above your knees to increase the tension on the hip abductors.

Frequently asked

What muscles does the seated alternate leg abduction and extension work?
The seated alternate leg abduction and extension primarily targets the abs, and also works the glutes as secondary muscles.
What equipment do you need for the seated alternate leg abduction and extension?
The seated alternate leg abduction and extension requires no equipment — just your body weight.
Is the seated alternate leg abduction and extension good for beginners?
Yes. The seated alternate leg abduction and extension is a beginner-friendly movement and a strong foundation to build on.

Related exercises

  • 45 Degrees Arms PlankIntermediate · abs, deltoids, obliques, and pectorals
  • 90 To 90Beginner · abs, glutes, obliques, and quadriceps
  • 90 To 90 SwitchIntermediate · abs, glutes, obliques, and quadriceps
  • Air BikeIntermediate · abs and obliques

Train this with a plan, not guesswork

Crucible builds the seated alternate leg abduction and extension into a precise program around your body, equipment, location, and time.

Download on the App Store