How to Do the Side Jackknife

The side jackknife has you lie on your side and lift your top leg while crunching your torso sideways. It works the obliques from both ends at once. It suits intermediate lifters who want a bodyweight side-core exercise with more challenge than heel touches.

Obliques BodyweightIntermediate

Log every set of your Side Jackknife in Superlift

Muscles worked

Primary

Obliques

Secondary

How to do the Side Jackknife

1
Lie on your side with legs stacked and your bottom arm extended or across your chest.
2
Place your top hand lightly behind your head.
3
Brace your abs and lift your top leg and your torso at the same time.
4
Bring your elbow and knee toward each other.
5
Squeeze your obliques at the top.
6
Lower slowly without resting on the floor.
7
Finish all reps, then switch sides.

Form cues to remember

Bring elbow and knee together
Don't roll backward
Squeeze at the top
Lower slowly

Common mistakes

Rolling onto your back

Stack your hips and shoulders so you stay on your side.

Pulling on the head

Keep your neck neutral and lead with your elbow.

Using momentum

Pause at the top and move slowly.

Moving only the leg

Lift your torso and leg together so the obliques crunch.

Sets and reps

Muscle growth	3 sets of 10–15 reps per side, 60 seconds rest
Endurance	2–3 sets of 15–20 reps per side
Strength	3 sets of 8–10 slow reps with a pause at the top

If your neck or lower back hurts, shorten the range and lift less. Avoid yanking your head.

Superlift for iPhone

Track your Side Jackknife and watch it go up

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