Jackknife Sit-up

Muscles worked: Abs
Abs
🔧 no equipment ↕ Flexion 🔁 reps Difficulty:

Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.

How to perform

Lie on your back with your feet and arms flat on the floor. Inhale to engage your core, then lift your arms and legs simultaneously until your thighs are at a 45-degree angle and your hands touch your shins, exhaling as you reach the top. This exercise targets your core, lower back, and glutes.

Muscles Worked

Rectus Abdominis
Secondary: External Obliques, Internal Obliques, Transverse Abdominis, Rectus Femoris, Glutes, Hamstrings, Erector Spinae, Quadriceps

Tips

Coordinate your inhales with the starting position and exhales with the lifting phase. Focus on slow, deliberate movements, pausing briefly at the highest point to intensify core engagement. Extend your legs and torso together, adjusting the range of motion as needed. Maintain a stable core throughout the exercise.

Similar exercises

Dumbbell jackknife sit up Hip flexors, Abs · 🔧 Dumbbells 3/10 Sit up Abs · 🔧 no equipment 2/10 Stability ball jackknife Hip flexors, Abs · 🔧 Stability Ball 3/10 Dumbbell sit up Abs, Hip flexors · 🔧 Dumbbells 3/10 Weighted sit up Abs · 🔧 plate 3/10
Feedback

Found a bug or have an idea?

MuscleTrain is actively being built. If something looks broken, or you have a suggestion, let us know — it really helps shape the app.