Core, Hips, Back
1. Lie on a mat with your arms extended to the side perpendicular to your body.
2. Raise both legs up vertically with your knees slightly bent.
1. Twist your waist and lower both legs to one side, until the side of your thigh is on the floor.
2. Raise your legs and twist your waist to the opposite direction, lowering both legs to the opposite side until the side of your thigh is on the floor. Repeat.
1. Maintain your knee position throughout the exercise.