Movement:
Stand with feet slightly apart. Take a big step forward. Keeping the torso as straight as possible. Lunge forward until the front thigh is horizontal to the floor (knee not pointing over the toe). Both knees (front and back) should be at a 90 degree angle. Return to the start position.
Then take a step backward and perform a reverse lunge, again both knees at 90 degree angles with no sliding by the knee joints. Fluidly return to the starting position and repeat.