Russian twist progression

From easiest to hardest. Move to the next step when you can do the current one with good form.

1. Bicycle crunch · Beginner · reps
   Lying on the back with the lower back pressed down, hands beside the head and shoulders lifted, legs in tabletop; one leg extends forward while the other knee pulls in and the torso twists so the opposite elbow/shoulder
2. Russian twist · Intermediate · reps
   Seated with knees bent and feet on the floor, torso leaning back about 45 degrees with a straight back, hands together in front of the chest, the rib cage rotates to one side then the other while hips and legs stay still