Side Jackknife
Muscles worked
table_chartRecommended sets and reps
These ranges vary depending on your training goal — adjust the load accordingly.
| Goal | Sets | Reps | Rest |
|---|---|---|---|
| boltStrength | 4–5 | 3–6 | 3–5 min |
| fitness_centerHypertrophy | 3–4 | 8–12 | 90 s |
| timerEndurance | 2–3 | 15–20 | 30–45 s |
About Side Jackknife
The side jackknife is a bodyweight exercise that specifically targets the obliques, combining a lateral trunk flexion with a simultaneous leg lift while lying on your side. The movement involves raising the torso and legs at the same time toward a central point, like scissors closing sideways, strongly contracting the obliques on the down side. Unlike classic crunches, which mainly work the rectus abdominis in the sagittal plane, this exercise loads the trunk in the frontal plane, a movement axis often underrepresented in standard ab programs. It's an excellent addition for building a balanced core, especially for athletes in rotation or lateral-flexion sports like golf, tennis, or combat sports.
check_circleBenefits
- check_circleSpecifically targets the obliques
- check_circleComplements classic crunches in the frontal plane
- check_circleBuilds a balanced core
- check_circleRequires no equipment
lightbulbExecution tips
- lightbulbRaise the torso and legs together for a scissor effect
- lightbulbKeep the movement controlled rather than fast
- lightbulbExhale at the point of peak contraction
- lightbulbTrain both sides evenly
warningCommon mistakes
- warningUsing momentum instead of actively contracting the obliques
- warningRaising only the legs or only the torso without combining both
- warningNeglecting one side compared to the other
- warningRushing the movement without control
helpFrequently asked questions
Which muscles does this exercise really work?expand_more
Mainly the obliques, with secondary involvement from the hip flexors and rectus abdominis.
Should I do the same number of reps on both sides?expand_more
Yes, to build a balanced trunk, it's important to train both sides with equal volume.
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