Core exercises: isometric and isotonic strength training

In this article, you’ll find seven core exercises described. The first three develop ‘held’ isometric strength and the other four moving (isotonic) strength. You could perform all the exercises in one focused ab training workout, or select three or four to add to your weight training or other suitable workouts.

Exercise suitability is indicated for all exercises.

1) The side plank

Overview:  Recommended as a safe and effective exercise for the obliques and quadratus lumborum (a key lumbar stabilising muscle). Recent research also shows this to be an excellent exercise for the lower abdominal muscles.

Level: All
Muscles targeted:
Obliques (internal and external)
Quadratus lumborum
Transversus abdominis

Technique: Lie on one side, ensuring your top hip is ‘stacked’ above the bottom hip. Push through your lower arm and leg and lift your body. Ensure that there is a straight line through your feet, hips and head. Rest your other arm along the side of your elevated body. Hold the position. Keep your elbow under your shoulder to avoid upper-body strain. Lower under control and repeat on opposite side.

Progression: Raise the top leg in the air and hold.

Perform: 5 sets of 10 sec. holds, progressing to 2-3 sets of 60 sec. Holds over 2-3 sets.


2) The gluteal bridge

Overview: Despite what you think, research indicates that this is more of a lower-back than a gluteal (butt) exercise.

Level: All

Muscles targeted:
Gluteus maximus
Erector spinae/multifidus.

Technique: Lie on the floor with your knees bent to a near 90-degree angle. Squeeze your gluteals and then push your hips up until there is a straight line through your knees and hip to your upper body. Keep your shoulders on the floor. Fold your arms across your chest. Don’t lift too high or flare your ribs as these will push your back into hyperextension. Hold the position.

Progression:  Extend one leg carefully ahead of you and hold the position without dropping or tilting your pelvis.

Perform: 5 sets of 10 second holds, progressing to 2-3 sets of 60 second holds.


3) ‘Birddog’ or ‘Superman’

Overview: Recommended as a safe and effective exercise for the lumbar (lower) and thoracic (upper) portions of the erector spinae (long back) muscle. This exercise also requires co-contraction of the abdominal wall muscles to stabilise your pelvis.

Level: New to exercise/intermediate.

Muscles targeted:
Thoracic and lumbar portions of erector spinae.

Technique: Assume a kneeling position with your hands below your shoulders and knees below hips. Set your lower back into neutral (neither overly rounded nor arched – you’ll see how to achieve this position in the video) and brace your abs slightly. Slowly lift one leg back and the opposite arm forward. Ensure that your back does not slip into extension and that your shoulders and pelvis do not tilt sideways. Slowly bring your leg and arm back and swap sides.

Progression: None

Perform: Hold and increase the duration up to a maximum of 20 sec. Do 5-10 reps, alternating sides after each hold over 2-4 sets.

Isotonic (exercises with movement) core exercises

Although these exercises are isotonic you must not swing or rock forward or backward when performing them. Instead, focus on initiating and completing the movement with your core muscles – this will ensure maximum muscle fibre recruitment. Lift and lower to a slow 3/4 count.

4) Active straight leg raise

Overview: Requires a strong static contraction of the abdominals to stabilise the lumbar spine against the load of the legs. It also requires a good active range of motion of the hamstrings.

Level: Intermediate/advanced

Muscles targeted:
Rectus abdominis
Abdominal wall
Hip flexors.

Technique: Lie on your back with knees bent. Set your lumbar spine in neutral and brace your abs. Lift one leg up straight into the air and ensure that your back does not move. Lift the other leg up, again keeping your back in place (if the back cannot be stabilised during this movement, the exercise is too advanced for you, and more static transversus stability control work will be needed first). Keeping one leg in the air, slowly lower the other down to the floor. Only go as far as you can, until you feel the lumbar spine start to move. Placing your fingers under your back will help you to gauge when this happens. Keep bracing the abs and then lift your leg slowly back up. Repeat with your other leg.

Perform: 5-10 reps, alternating legs over 2-4 sets.

5) Oblique crunch

Overview: A good exercise for both the obliques and the abdominals.

Level: Intermediate.

Muscles targeted:
Rectus abdominis

Technique: Lie on your back and place your right ankle on your left knee. Place your right arm on the floor and out to the side. Keep the right shoulder down, and curl the left shoulder up to the right knee. ‘Crunch’ (squeeze the abs) at the top and return slowly, under control. Keep your left hand in line with your ear throughout the movement. Avoid ‘head nodding’, keep it off the floor and look forward throughout.

Progression: Hold a light dumbbell in your hand by your head to add resistance. Keep your arm still so that you are forced to raise the dumbbell using your abs and not your arm.

Perform: 15 reps over 2-4 sets.


6) Lying side hip abduction

Overview: This exercise isolates the use of gluteus medius (upper, outer portion of the butt). Strength in this muscle group has been shown to be useful in preventing lower-limb injuries in female athletes.

Level: Especially suitable for those new to exercise.

Muscles targeted:
Gluteus medius.

Technique: Lie on your side and set your pelvis so that your top hip is stacked above your lower hip. Roll your shoulders forward a little and brace your abs to control your position. Lift the top leg slowly up and down.

Progression: Weight the top leg with an ankle weight or tie a resistance band between your ankles and pull the band apart as you lift the leg.

Perform: 20-30 reps, each side in turn over 3 sets.

7) Lying windscreen wipers

Overview: An active mobility exercise that works the obliques and assists trunk rotation.

Level: Advanced

Muscles targeted:
Rectus abdominis

Technique: Lie on your back with arms out to your sides. Lift your legs straight up in the air until your hips are at 90 degrees. Set your lumbar spine in neutral and aim to keep it there throughout. Keeping your legs straight and maintaining the hip angle move your legs from side to side, controlling any movement in the trunk. Go as far as you can. Remain in control of the movement and keep your upper back and shoulders on the floor.

Progression: Increase the speed of the movement.

Perform: 20 reps left to right over 4 sets.

Share this

Follow us