Jackknife On Ball
Jackknife On Ball Exercise Description
The stability ball jackknife is a dynamic plank that challenges anterior core stability while your lower body moves. From a push-up position with your shins on the ball, you draw your knees toward your chest to roll the ball in, then return to a straight-line plank. The trunk’s job is anti‑extension: keep the ribs down and pelvis level so the low back stays neutral as the hips and knees flex and extend. Primary work is in the rectus abdominis and other anterior core musculature, with the hip flexors driving the tuck; the shoulders and serratus anterior stabilize the shoulder girdle. Performed with controlled tempo and full-body tension, this drill reinforces bracing, shoulder stability, and precise hip motion without lumbar sag or excessive spinal rounding.
- Muscle Groups: Abs, Core, Waist
- Target Muscles: Rectus Abdominis
- Assisting Muscles: External Obliques, Iliacus, Psoas Major
- Stabilizing Muscles: Gluteus Maximus, Serratus Anterior, Transversus Abdominis, Trapezius - Lower Fibers
- Body Area: Upper Body
- Body Parts: Core, Torso
- Body Surface: Front
- Body Symmetry: Bilateral
- Equipment: Stability Ball
- Exercise Patterns: Other
- Exercise Type: Strength
- Functional Grouping: Trunk Flexors
- Joint Involvement: Multi-joint
- Muscle Location: Stomach
- Movement Direction: Horizontal
- Muscle Position: Anterior
- Gender: Female
How To Do The Jackknife On Ball Exercise
‘- Place hands on the floor under shoulders, fingers spread; set shins/laces on the ball. Form a straight line from head to heels.
– Brace lightly: draw ribs down, engage glutes, and maintain a neutral spine and pelvis.
– “Press the floor away” to keep shoulders stable and shoulder blades flush to the rib cage.
– Inhale to prepare. Exhale as you flex hips and knees to draw the ball toward your chest.
– Keep the back flat and pelvis level; move at the hips and knees, not by rounding the low back.
– Pause briefly when knees are under hips; avoid shrugging or collapsing the chest.
– Reverse with control, extending hips and knees to roll the ball back to a straight-line plank without letting the low back sag.
– Keep head neutral with gaze slightly ahead; breathe continuously and maintain even pressure through both hands.
– Adjust difficulty by placing more or less of your legs on the ball or by using a shorter, controlled range while you maintain alignment.
Jackknife On Ball Tips
‘- Start in a straight line from head to heels with shins or laces on the ball and hands under your shoulders.
– Lightly brace by drawing the ribs down, engaging the glutes, and keeping the spine and pelvis neutral.
– “Press the floor away” so the shoulders stay stable and the shoulder blades stay flush to the rib cage.
– Exhale as you flex your hips and knees to roll the ball toward your chest.
– Keep your back flat and pelvis level; let the movement come from the hips and knees, not from rounding the low back.
– Briefly pause when your knees are under your hips, without shrugging or letting the chest collapse.
– Roll the ball back with control by extending hips and knees, returning to a straight-line plank without letting the low back sag.
– Keep your head neutral with your gaze slightly ahead and maintain even pressure through both hands.
– To adjust difficulty, change how much of your legs rest on the ball or use a shorter, controlled range while you maintain alignment.
Jackknife On Ball Beginner Introduction
The stability ball jackknife is a challenging plank variation that blends core strength with balance. In this movement, the body begins in a straight, push-up–style position with the lower legs supported on a stability ball. As the ball rolls toward the body and then back out again, the front of the core resists arching or collapsing, creating a strong demand on the abs while the legs bend and straighten.
This exercise centers on controlling the midsection while the hips and knees travel forward and back. The abs and other core muscles at the front of the torso handle most of the effort, while the hip flexors drive the tucking motion. At the same time, the shoulders, upper body, and muscles around the shoulder blades and rib area contribute stability so the upper half stays steady. A smooth, deliberate rhythm and consistent body tension highlight precise hip movement, reduced strain through the lower back, and solid support around the shoulder joints. Difficulty shifts depending on how much of the legs rest on the ball and how far the ball moves.