Jackknife On Exercise Ball, One-Legged

General And Specifics

• this ab exercise strengthens the core and the hip flexor, it also requires stability

Starting Position

• place the hands about shoulder width on the ground
• lay the shins onto the gym ball, your legs are stretched out, balance your body
• lift one leg
• hold the back straight and the hip up

Correct Execution

• angle the leg which lies on the ball and pull it in direction to the hip
• the gym ball rolls in direction hip, too
• pull the leg forwards until it is vertical to the ground
• the ball is under your foot in the final position, hold it for a bit
• stretch the leg out again and roll the ball back into the starting position
• the upper body is stable and straight during this exercise
• repeat this several times, also with your other leg