Begin lying on your back with your knees bent. Your feet should be shoulder-width apart.

Perform the pelvic tilt and flatten your back onto the floor. Next, perform the abdominal hollowing action, pulling your tummy button in. Finally, reach forwards with your fingers towards your heels so that your trunk bends and your shoulders lift from the floor.

The action of this exercise is to bend the trunk, not to sit up. The bottom part of the shoulder blades should stay in contact with the ground throughout the movement. As you perform the abdominal hollowing action, breathe out. Breathe in as you release the movement.

Reaching forwards (along the ground) towards the heels, rather than upwards for the knees, encourages the correct trunk bending action.

Begin lying on the floor on your back with your knees bent, feet flat. Your knees and feet should be about 20-30 cm (8-12 inches) apart.

Abdominal hollow to tighten your abdominal muscles, and then reach past the outside of your left knee with your right hand. At the same time, pull the left side of your pelvis towards you. Pause and then reverse the action, reaching to the right.

The aim of this exercise is to tone the oblique abdominals. To achieve this, the lower part of the trunk must take part in the action, so the hip pull is essential to the exercise.

To emphasise the hip pull action, initially ask someone to press onto your hip as you pull. This will make isolating the action easier. Remember to lift only one hip at a time!

Lie on the floor and draw your knees up to rest above your hips – feet off the floor – moving one knee at a time. You can place your fingertips on either side of your lower abdomen below your tummy button to feel the muscle contraction.

Tighten your tummy muscles to hollow your abdomen, and maintain this muscle contraction throughout the exercise. Slowly lower one leg, keeping it bent, until your foot touches the floor. Raise the leg and, when it is in the starting position again, begin to lower the other leg.

The foot should be lowered directly downwards, keeping it close to the buttocks. Do not allow the leg to straighten as this makes the exercise considerably more intense.

Monitor the position of your tummy and pelvis with your fingertips. If you feel your tummy bulging (‘ballooning’) rather than staying flat, or if you feel your pelvis move, stop the exercise.

Sit on the floor with your knees hip-width apart and bent, and feet flat (the crook or hook sitting position). Straighten your back, bracing your shoulders back slightly into the V sit position (exercise 31, page 111). Hold your arms to the sides of your knees, palms facing inwards.

Tighten your tummy muscles to hollow your abdomen, and maintain this muscle contraction throughout the exercise. Straighten your right leg keeping your left foot firmly on the floor. Hold the straight leg position for 5 seconds and then lower. Repeat the action with the left leg.

As you straighten your leg, maintain the hip angle so that the leg is held at 45 degrees to the mat. Lowering the leg towards the mat increases the leverage effect on the leg and makes the action considerably harder.