Alternating Lying Leg Jackknife
Incinerate your core with this focused floor exercise. By alternating limbs, you’ll target your obliques and lower abs for a stronger, more stable midline and a shredded aesthetic.
The Alternating Lying Leg Jackknife mainly works the core, with help from the quads. No equipment needed: it uses just your bodyweight.
Optional Equipment
Alternating Lying Leg Jackknife Muscles Worked
Primary
Abdominals (rectus abdominis); Hip Flexor (iliopsoas)
Secondary
Obliques; Quads (quadriceps femoris)
How to do the Alternating Lying Leg Jackknife
Setup
Lie flat on your back on a mat with your legs extended straight and arms stretched overhead. Your body should form a long, straight line.
Movement
Engage Core: Tighten your abdominal muscles and exhale as you start the movement.
Lift Arm and Leg: Simultaneously lift one leg while reaching your opposite arm toward the raised foot, performing a crunching motion to bring your torso slightly off the floor.
Controlled Descent: Inhale as you slowly lower your arm and leg back down to the starting position with control, maintaining tension in the core throughout.
Repeat: Alternate to the opposite arm and leg, ensuring that your lower back stays pressed firmly against the mat at all times.
Tips for Success
Focus on moving with deliberate control rather than using momentum.
Keep your spine in a neutral position to avoid strain.
Ensure you are lifting your shoulders off the ground far enough to engage the abs fully with each repetition.
Alternating Lying Leg Jackknife FAQs
What muscles does the Alternating Lying Leg Jackknife work?
The Alternating Lying Leg Jackknife mainly works the core, with help from the quads. The main muscles are the rectus abdominis and iliopsoas.
What equipment do you need for the Alternating Lying Leg Jackknife?
None. The Alternating Lying Leg Jackknife is a bodyweight exercise, so you can do it anywhere.
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